Co-reporter:Adrian A. Accurso;Mac Delaney;Jeff O'Brien; Hyonny Kim; Peter M. Iovine; David Díaz Díaz; M. G. Finn
Chemistry - A European Journal 2014 Volume 20( Issue 34) pp:10710-10719
Publication Date(Web):
DOI:10.1002/chem.201400137
Abstract
Electrically conductive adhesive polymers offer many potential advantages relative to SnPb solders, including reduced toxicity, low cost, low processing temperatures, and the ability to make application-specific formulations. Polymers generated from the copper(I)-catalyzed cycloaddition (CuAAC) reaction between multivalent azides and alkynes have previously been identified as strong metal-binding adhesives. Herein we demonstrate that the performance of these materials can be remarkably improved by the incorporation of a flexibility-inducing difunctionalized component and a tertiary amine additive in optimized concentrations. The best formulations were identified by means of rapid adhesion testing of a library of potential candidates by using a custom-built instrument and validated in an American Society for Testing and Materials (ASTM)-standard lap-shear test. Characteristic phase transitions were identified by differential scanning calorimetry (DSC) for adhesives with and without the additives as a function of curing temperature. The incorporation of flexible components was found to more than double the strength of the adhesive. Moreover, the adhesive was made electrically conductive by the inclusion of 20 wt % silver-coated copper flakes and further improved in this regard by the incorporation of multiwalled carbon nanotubes in the formulation.
Co-reporter:Zhaojun Yin, Marta Comellas-Aragones, Sudipa Chowdhury, Philip Bentley, Katarzyna Kaczanowska, Lbachir BenMohamed, Jeffrey C. Gildersleeve, M. G. Finn, and Xuefei Huang
ACS Chemical Biology 2013 Volume 8(Issue 6) pp:1253
Publication Date(Web):March 18, 2013
DOI:10.1021/cb400060x
The development of an effective immunotherapy is an attractive strategy toward cancer treatment. Tumor associated carbohydrate antigens (TACAs) are overexpressed on a variety of cancer cell surfaces, which present tempting targets for anticancer vaccine development. However, such carbohydrates are often poorly immunogenic. To overcome this challenge, we show here that the display of a very weak TACA, the monomeric Tn antigen, on bacteriophage Qβ virus-like particles elicits powerful humoral responses to the carbohydrate. The effects of adjuvants, antigen display pattern, and vaccine dose on the strength and subclasses of antibody responses were established. The local density of antigen rather than the total amount of antigen administered was found to be crucial for induction of high Tn-specific IgG titers. The ability to display antigens in an organized and high density manner is a key advantage of virus-like particles such as Qβ as vaccine carriers. Glycan microarray analysis showed that the antibodies generated were highly selective toward Tn antigens. Furthermore, Qβ elicited much higher levels of IgG antibodies than other types of virus-like particles, and the IgG antibodies produced reacted strongly with the native Tn antigens on human leukemia cells. Thus, Qβ presents a highly attractive platform for the development of carbohydrate-based anticancer vaccines.
Co-reporter:Sreeman K. Mamidyala ; Sanjay Dutta ; Boris A. Chrunyk ; Cathy Préville ; Hong Wang ; Jane M. Withka ; Alexander McColl ; Timothy A. Subashi ; Steven J. Hawrylik ; Matthew C. Griffor ; Sung Kim ; Jeffrey A. Pfefferkorn ; David A. Price ; Elnaz Menhaji-Klotz ; Vincent Mascitti ;M.G. Finn
Journal of the American Chemical Society 2012 Volume 134(Issue 4) pp:1978-1981
Publication Date(Web):January 24, 2012
DOI:10.1021/ja2104679
The asialoglycoprotein receptor (ASGPR) is a high-capacity galactose-binding receptor expressed on hepatocytes that binds its native substrates with low affinity. More potent ligands are of interest for hepatic delivery of therapeutic agents. We report several classes of galactosyl analogues with varied substitution at the anomeric, C2-, C5-, and C6-positions. Significant increases in binding affinity were noted for several trifluoromethylacetamide derivatives without covalent attachment to the protein. A variety of new ligands were obtained with affinity for ASGPR as good as or better than that of the parent N-acetylgalactosamine, showing that modification on either side of the key C3,C4-diol moiety is well tolerated, consistent with previous models of a shallow binding pocket. The galactosyl pyranose motif therefore offers many opportunities for the attachment of other functional units or payloads while retaining low-micromolar or better affinity for the ASGPR.
Co-reporter:Alexander A. Kislukhin ; Cody J. Higginson ; Vu P. Hong
Journal of the American Chemical Society 2012 Volume 134(Issue 14) pp:6491-6497
Publication Date(Web):March 28, 2012
DOI:10.1021/ja301491h
Oxanorbornadienedicarboxylate (OND) reagents were explored for purposes of binding and releasing drugs from serum albumins as representative macromolecular carriers. Being highly reactive Michael acceptors, ONDs form adducts with thiols and amines, which then undergo retro-Diels–Alder fragmentation. A study of more than 30 model adducts revealed a number of modifications that can be used to influence adduct stability. For the most reactive OND linkers, the labeling of the single available bovine serum albumin (BSA) cysteine residue was complete within minutes at a mid-micromolar concentration of reactants. While a selectivity of greater than 1000-fold for thiol over amine was observed with model amino acids, the labeling of protein amines with ONDs is fast enough to be practical, as demonstrated by the reaction with thiol-depleted BSA. The OND–amine adducts were found to be up to 15 times more stable than OND–thiol adducts, and to be sensitive to acid by virtue of a stereochemically dependent acceleration of cycloreversion. The release rate of fluorescent cargo from serum albumins was tuned by selecting the coupling partners: the available half-lives ranged from 40 min to 7 days at 37 °C. Such versatility of release profiles from protein carriers, controlled by the nature of the OND linkage, is a useful addition to the drug delivery toolbox.
Co-reporter:Marisa L. Hovlid, Nicole F. Steinmetz, Burkhardt Laufer, Jolene L. Lau, Jane Kuzelka, Qian Wang, Timo Hyypiä, Glen R. Nemerow, Horst Kessler, Marianne Manchester and M. G. Finn
Nanoscale 2012 vol. 4(Issue 12) pp:3698-3705
Publication Date(Web):15 May 2012
DOI:10.1039/C2NR30571B
Viral nanoparticles (VNPs) are structurally regular, highly stable, tunable nanomaterials that can be conveniently produced in high yields. Unmodified VNPs from plants and bacteria generally do not show tissue specificity or high selectivity in binding to or entry into mammalian cells. They are, however, malleable by both genetic and chemical means, making them useful scaffolds for the display of large numbers of cell- and tissue-targeting ligands, imaging moieties, and/or therapeutic agents in a well-defined manner. Capitalizing on this attribute, we modified the genetic sequence of the Cowpea mosaic virus (CPMV) coat protein to display an RGD oligopeptide sequence derived from human adenovirus type 2 (HAdV-2). Concurrently, wild-type CPMV was modified via NHS acylation and Cu(I)-catalyzed azide–alkyne cycloaddition (CuAAC) chemistry to attach an integrin-binding cyclic RGD peptide. Both types of particles showed strong and selective affinity for several different cancer cell lines that express RGD-binding integrin receptors.
Co-reporter:Stanislav I. Presolski, Sreeman K. Mamidyala, Florian Manzenrieder, and M.G. Finn
ACS Combinatorial Science 2012 Volume 14(Issue 10) pp:527
Publication Date(Web):September 4, 2012
DOI:10.1021/co300076k
The copper-catalyzed azide–alkyne cycloaddition click reaction is a valuable process for the synthesis of libraries of drug candidates, derivatized polymers and materials, and a wide variety of other functional molecules. In some circumstances, the removal of the copper catalyst is both necessary and inconvenient. We describe here two immobilized forms of a Cu-binding ligand that has been shown to accelerate triazole formation under many different conditions, using different resin supports that are appropriate for aqueous or organic solvents. Copper leaching from these resins was modest, allowing them to be reused in many reaction/filtration cycles without recharging with metal ion. The utility of this catalyst form was demonstrated in the convenient synthesis of 20 N-acetylgalactosamine derivatives for biological testing.Keywords: copper catalyst; CuAAC click reactions; resin-supported catalysts
Co-reporter:Jason D. Fiedler, Cody Higginson, Marisa L. Hovlid, Alexander A. Kislukhin, Alexandra Castillejos, Florian Manzenrieder, Melody G. Campbell, Neil R. Voss, Clinton S. Potter, Bridget Carragher, and M.G. Finn
Biomacromolecules 2012 Volume 13(Issue 8) pp:
Publication Date(Web):July 25, 2012
DOI:10.1021/bm300590x
The single-coat protein (CP) of bacteriophage Qβ self-assembles into T = 3 icosahedral virus-like particles (VLPs), of interest for a wide range of applications. These VLPs are very stable, but identification of the specific molecular determinants of this stability is lacking. To investigate these determinants along with manipulations that confer more capabilities to our VLP material, we manipulated the CP primary structure to test the importance of various putative stabilizing interactions. Optimization of a procedure to incorporate fused CP subunits allowed for good control over the average number of covalent dimers in each VLP. We confirmed that the disulfide linkages are the most important stabilizing elements for the capsid and that acidic conditions significantly enhance the resistance of VLPs to thermal degradation. Interdimer interactions were found to be less important for VLP assembly than intradimer interactions. Finally, a single point mutation in the CP resulted in a population of smaller VLPs in three distinct structural forms.
Co-reporter:Jin-Kyu Rhee, Michael Baksh, Corwin Nycholat, James C. Paulson, Hiroaki Kitagishi, and M. G. Finn
Biomacromolecules 2012 Volume 13(Issue 8) pp:
Publication Date(Web):July 24, 2012
DOI:10.1021/bm300578p
Virus-like particles (VLPs) have proven to be versatile platforms for chemical and genetic functionalization for a variety of purposes in biomedicine, catalysis, and materials science. We describe here the simultaneous modification of the bacteriophage Qβ VLP with a metalloporphyrin derivative for photodynamic therapy and a glycan ligand for specific targeting of cells bearing the CD22 receptor. This application benefits from the presence of the targeting function and the delivery of a high local concentration of singlet oxygen-generating payload.
Co-reporter:Jonathan K. Pokorski ; Kurt Breitenkamp ; Lars O. Liepold ; Shefah Qazi ;M.G. Finn
Journal of the American Chemical Society 2011 Volume 133(Issue 24) pp:9242-9245
Publication Date(Web):May 31, 2011
DOI:10.1021/ja203286n
Viruses and virus-like particles (VLPs) are useful tools in biomedical research. Their defined structural attributes make them attractive platforms for engineered interactions over large molecular surface areas. In this report, we describe the use of VLPs as multivalent macroinitiators for atom transfer radical polymerization. The introduction of chemically reactive monomers during polymerization provides a robust platform for post-synthetic modification via the copper-catalyzed azide–alkyne cycloaddition reaction. These results provide the basis to construct nanoparticle delivery vehicles and imaging agents using protein–polymer conjugates.
Co-reporter:Jin-Kyu Rhee, Marisa Hovlid, Jason D. Fiedler, Steven D. Brown, Florian Manzenrieder, Hiroaki Kitagishi, Corwin Nycholat, James C. Paulson, and M. G. Finn
Biomacromolecules 2011 Volume 12(Issue 11) pp:
Publication Date(Web):October 13, 2011
DOI:10.1021/bm200983k
Qβ virus-like particles encapsulating multiple copies of fluorescent proteins were generated in high yields using a modular system enhanced by specific engineered RNA–protein interactions. The resulting particles were structurally indistinguishable from recombinant Qβ alone. The encapsidated proteins were nearly identical in photochemical properties to monomeric analogues, were more stable toward thermal degradation, and were protected from proteolytic cleavage. Residues on the outer capsid surface were chemically derivatized by acylation and azide–alkyne cycloaddition without affecting the fluorescence properties of the packaged proteins. A high-affinity carbohydrate-based ligand of the CD22 receptor was thereby attached, and specific cell labeling by the particles was successfully detected by flow cytometry and confocal laser microscopy.
Co-reporter:Adrian A. Accurso, So-Hye Cho, Asmarah Amin, Vladimir A. Potapov, Svetlana V. Amosova, and M. G. Finn
The Journal of Organic Chemistry 2011 Volume 76(Issue 11) pp:4392-4395
Publication Date(Web):May 5, 2011
DOI:10.1021/jo102440k
Sulfur-, selenium-, and nitrogen-containing compounds bearing leaving groups in the β-position undergo facile substitution chemistry enabled by anchimeric assistance. Here we provide direct comparisons between such systems in the rigid bicyclo[3.3.1]nonane framework easily derived from 1,5-cyclooctadiene. For a series of dichloride electrophiles of this type, the relative reactivities were found to be Se ≫ (alkyl)N > S ≥ (propargyl)N > (phenyl)N, with the reaction rates at the two extremes differing by more than 3 orders of magnitude. For the N-alkyl case, substitution rates were largely independent of the trapping nucleophile but were strongly dependent on solvent, showing that the process is controlled by the formation of the high-energy three-membered cationic intermediate.
Co-reporter:Jolene L. Lau, Michael M. Baksh, Jason D. Fiedler, Steven D. Brown, Amanda Kussrow, Darryl J. Bornhop, Phillip Ordoukhanian, and M. G. Finn
ACS Nano 2011 Volume 5(Issue 10) pp:7722
Publication Date(Web):September 7, 2011
DOI:10.1021/nn2006927
A high-affinity RNA aptamer (Kd = 50 nM) was efficiently identified by SELEX against a heteroaryldihydropyrimidine structure, chosen as a representative drug-like molecule with no cross reactivity with mammalian or bacterial cells. This aptamer, its weaker-binding variants, and a known aptamer against theophylline were each embedded in a longer RNA sequence that was encapsidated inside a virus-like particle by a convenient expression technique. These nucleoprotein particles were shown by backscattering interferometry to bind to the small-molecule ligands with affinities similar to those of the free (nonencapsidated) aptamers. The system therefore comprises a general approach to the production and sequestration of functional RNA molecules, characterized by a convenient label-free analytical technique.Keywords: aptamers; backscattering interferometry; RNA packaging; virus-like particles
Co-reporter:Dr. Florian Manzenrieder;Dr. Robert Luxenhofer;Dr. Marco Retzlaff; Rainer Jordan; M. G. Finn
Angewandte Chemie International Edition 2011 Volume 50( Issue 11) pp:2601-2605
Publication Date(Web):
DOI:10.1002/anie.201006134
Co-reporter:Dr. Jonathan K. Pokorski;Marisa L. Hovlid ; M. G. Finn
ChemBioChem 2011 Volume 12( Issue 16) pp:2441-2447
Publication Date(Web):
DOI:10.1002/cbic.201100469
Abstract
Structurally uniform protein nanoparticles derived from the self-assembly of viral capsid proteins are attractive platforms for the multivalent display of cell-targeting motifs for use in nanomedicine. Virus-based nanoparticles are of particular interest because the scaffold can be manipulated both genetically and chemically to simultaneously display targeting groups and carry a functional payload. Here, we displayed the human epidermal growth factor (EGF) on the exterior surface of bacteriophage Qβ as a C-terminal genetic fusion to the Qβ capsid protein. The co-assembly of wild-type Qβ and EGF-modified subunits resulted in structurally homogeneous nanoparticles displaying between 5 and 12 copies of EGF on their exterior surface. The particles were found to be amenable to bioconjugation by standard methods as well as the high-fidelity copper-catalyzed azide–alkyne cycloaddition reaction (CuAAC). Such chemical derivatization did not impair the ability of the particles to specifically interact with the EGF receptor. Additionally, the particle-displayed EGF remained biologically active promoting autophosphorylation of the EGF receptor and apoptosis of A431 cells. These results suggest that hybrid Qβ-EGF nanoparticles could be useful vehicles for targeted delivery of imaging and/or therapeutic agents.
Co-reporter:Dr. Florian Manzenrieder;Dr. Robert Luxenhofer;Dr. Marco Retzlaff; Rainer Jordan; M. G. Finn
Angewandte Chemie 2011 Volume 123( Issue 11) pp:2649-2653
Publication Date(Web):
DOI:10.1002/ange.201006134
Co-reporter:Dr. Ama Kussrow;Dr. Michael M. Baksh; Darryl J. Bornhop; M. G. Finn
ChemBioChem 2011 Volume 12( Issue 3) pp:367-370
Publication Date(Web):
DOI:10.1002/cbic.201000671
Co-reporter:Stanislav I. Presolski ; Vu Hong ; So-Hye Cho ;M.G. Finn
Journal of the American Chemical Society 2010 Volume 132(Issue 41) pp:14570-14576
Publication Date(Web):September 23, 2010
DOI:10.1021/ja105743g
Tris(heterocyclemethyl)amines containing mixtures of 1,2,3-triazolyl, 2-benzimidazoyl, and 2-pyridyl components were prepared for ligand acceleration of the copper-catalyzed azide−alkyne cycloaddition reaction. Two classes of ligands were identified: those that give rise to high reaction rates in coordinating solvents but inhibit the process when used in excess relative to copper and those that provide for fast catalysis in water and are not inhibitory in excess. Several “mixed” ligands were identified that performed well under both types of conditions. Kinetics measurements as a function of ligand:metal ratio and catalyst concentration were found to be consistent with an active Cu2L formulation. Since strongly bound chelating agents are not always the most effective, achieving optimal rates requires an assessment of the potential donor molecules in the reaction mixture. Simple rules are provided to guide the user in the choice of effective ligands and reaction conditions to suit most classes of substrates, solvents, and concentrations.
Co-reporter:Rena D. Astronomo, Eiton Kaltgrad, Andrew K. Udit, Sheng-Kai Wang, Katie J. Doores, Cheng-Yuan Huang, Ralph Pantophlet, James C. Paulson, Chi-Huey Wong, M.G. Finn, Dennis R. Burton
Chemistry & Biology 2010 Volume 17(Issue 4) pp:357-370
Publication Date(Web):23 April 2010
DOI:10.1016/j.chembiol.2010.03.012
The broadly neutralizing antibody 2G12 recognizes a conserved cluster of high-mannose glycans on the surface envelope spike of HIV, suggesting that the “glycan shield” defense of the virus can be breached and may, under the right circumstances, serve as a vaccine target. In an attempt to recreate features of the glycan shield semisynthetically, oligomannosides were coupled to surface lysines on the icosahedral capsids of bacteriophage Qβ and cowpea mosaic virus (CPMV). The Qβ glycoconjugates, but not CPMV, presented oligomannose clusters that bind the antibody 2G12 with high affinity. However, antibodies against these 2G12 epitopes were not detected in immunized rabbits. Rather, alternative oligomannose epitopes on the conjugates were immunodominant and elicited high titers of anti-mannose antibodies that do not crossreact with the HIV envelope. The results presented reveal important design considerations for a carbohydrate-based vaccine component for HIV.
Co-reporter:Vu Hong, Nicole F. Steinmetz, Marianne Manchester, and M. G. Finn
Bioconjugate Chemistry 2010 Volume 21(Issue 10) pp:1912
Publication Date(Web):October 1, 2010
DOI:10.1021/bc100272z
The copper-catalyzed azide−alkyne cycloaddition (CuAAC) reaction, optimized for biological molecules in aqueous buffers, has been shown to rapidly label mammalian cells in culture with no loss in cell viability. Metabolic uptake and display of the azide derivative of N-acetylmannosamine developed by Bertozzi, followed by CuAAC ligation using sodium ascorbate and the ligand tris(hydroxypropyltriazolyl)methylamine (THPTA), gave rise to abundant covalent attachment of dye−alkyne reactants. THPTA serves both to accelerate the CuAAC reaction and to protect the cells from damage by oxidative agents produced by the Cu-catalyzed reduction of oxygen by ascorbate, which is required to maintain the metal in the active +1 oxidation state. This procedure extends the application of this fastest of azide-based bioorthogonal reactions to the exterior of living cells.
Co-reporter:Deboshri Banerjee Dr.;Allen P. Liu Dr.;Neil R. Voss Dr.;Sra L. Schmid
ChemBioChem 2010 Volume 11( Issue 9) pp:1273-1279
Publication Date(Web):
DOI:10.1002/cbic.201000125
Abstract
The structurally regular and stable self-assembled capsids derived from viruses can be used as scaffolds for the display of multiple copies of cell- and tissue-targeting molecules and therapeutic agents in a convenient and well-defined manner. The human iron-transfer protein transferrin, a high affinity ligand for receptors upregulated in a variety of cancers, has been arrayed on the exterior surface of the protein capsid of bacteriophage Qβ. Selective oxidation of the sialic acid residues on the glycan chains of transferrin was followed by introduction of a terminal alkyne functionality through an oxime linkage. Attachment of the protein to azide-functionalized Qβ capsid particles in an orientation allowing access to the receptor binding site was accomplished by the CuI-catalyzed azide–alkyne cycloaddition (CuAAC) click reaction. Transferrin conjugation to Qβ particles allowed specific recognition by transferrin receptors and cellular internalization through clathrin-mediated endocytosis, as determined by fluorescence microscopy on cells expressing GFP-labeled clathrin light chains. By testing Qβ particles bearing different numbers of transferrin molecules, it was demonstrated that cellular uptake was proportional to ligand density, but that internalization was inhibited by equivalent concentrations of free transferrin. These results suggest that cell targeting with transferrin can be improved by local concentration (avidity) effects.
Co-reporter:Dr. Takayoshi Suzuki;Yosuke Ota;Yuki Kasuya;Dr. Motoh Mutsuga;Dr. Yoko Kawamura;Dr. Hiroki Tsumoto;Dr. Hidehiko Nakagawa; M.G. Finn; Naoki Miyata
Angewandte Chemie International Edition 2010 Volume 49( Issue 38) pp:6817-6820
Publication Date(Web):
DOI:10.1002/anie.201002205
Co-reporter:Jason D. Fiedler;Steven D. Brown;Jolene L. Lau ; M. G. Finn
Angewandte Chemie International Edition 2010 Volume 49( Issue 50) pp:9648-9651
Publication Date(Web):
DOI:10.1002/anie.201005243
Co-reporter:Jason D. Fiedler;Steven D. Brown;Jolene L. Lau ; M. G. Finn
Angewandte Chemie 2010 Volume 122( Issue 50) pp:9842-9845
Publication Date(Web):
DOI:10.1002/ange.201005243
Co-reporter:Nicole F. Steinmetz ; Vu Hong ; Erik D. Spoerke ; Ping Lu ; Kurt Breitenkamp ; M. G. Finn ;Marianne Manchester
Journal of the American Chemical Society 2009 Volume 131(Issue 47) pp:17093-17095
Publication Date(Web):November 11, 2009
DOI:10.1021/ja902293w
Fullerenes such as C60 show promise as functional components in several emerging technologies. For biomedical applications, C60 has been used in gene- and drug-delivery vectors, as imaging agents, and as photosensitizers in cancer therapy. A major drawback of C60 for bioapplications is its insolubility in water. To overcome this limitation, we covalently attached C60 derivatives to Cowpea mosaic virus and bacteriophage Qβ virus-like particles, which are examples of naturally occurring viral nanoparticle (VNP) structures that have been shown to be promising candidates for biomedicine. Two different labeling strategies were employed, giving rise to water-soluble, stable VNP−C60 and VNP−PEG-C60 conjugates. Samples were characterized using a combination of transmission electron microscopy, scanning transmission electron microscopy (STEM), gel electrophoresis, size-exclusion chromatography, dynamic light scattering, and Western blotting. “Click” chemistry bioconjugation using a poly(ethylene glycol) (PEG)-modified propargyl-O-PEG-C60 derivative gave rise to high loadings of fullerene on the VNP surface, as indicated by the imaging of individual C60 units using STEM. The cellular uptake of dye-labeled VNP−PEG-C60 complexes in a human cancer cell line was found by confocal microscopy to be robust, showing that cell internalization was not inhibited by the attached C60 units. These results open the door for the development of novel therapeutic devices with potential applications in photoactivated tumor therapy.
Co-reporter:Amanda Kussrow, Eiton Kaltgrad, Mark L. Wolfenden, Mary J. Cloninger, M. G. Finn and Darryl J. Bornhop
Analytical Chemistry 2009 Volume 81(Issue 12) pp:4889
Publication Date(Web):May 22, 2009
DOI:10.1021/ac900569c
Carbohydrate−protein binding is important to many areas of biochemistry. Here, backscattering interferometry (BSI) has been shown to be a convenient and sensitive method for obtaining quantitative information about the strengths and selectivities of such interactions. The surfaces of glass microfluidic channels were covalently modified with extravidin, to which biotinylated lectins were subsequently attached by incubation and washing. The binding of unmodified carbohydrates to the resulting avidin-immobilized lectins was monitored by BSI. Dose−response curves that were generated within several minutes and were highly reproducible in multiple wash/measure cycles provided adsorption coefficients that showed mannose to bind to concanavalin A (conA) with 3.7 times greater affinity than glucose consistent with literature values. Galactose was observed to bind selectively and with similar affinity to the lectin BS-1. The avidities of polyvalent sugar-coated virus particles for immobilized conA were much higher than monovalent glycans, with increases of 60−200 fold per glycan when arrayed on the exterior surface of cowpea mosaic virus or bacteriophage Qβ. Sugar-functionalized PAMAM dendrimers showed size-dependent adsorption, which was consistent with the expected density of lectins on the surface. The sensitivity of BSI matches or exceeds that of surface plasmon resonance and quartz crystal microbalance techniques, and is sensitive to the number of binding events, rather than changes in mass. The operational simplicity and generality of BSI, along with the near-native conditions under which the target binding proteins are immobilized, make BSI an attractive method for the quantitative characterization of the binding functions of lectins and other proteins.
Co-reporter:Steven D. Brown, Jason D. Fiedler and M. G. Finn
Biochemistry 2009 Volume 48(Issue 47) pp:
Publication Date(Web):October 22, 2009
DOI:10.1021/bi901306p
Bacteriophage Qβ coat protein forms uniform virus-like particles when expressed recombinantly in a variety of organisms. We have inserted the IgG-binding Z domain at the carboxy terminus of the coat protein and coexpressed this chimeric subunit with native coat protein to create hybrid, IgG-binding virus-like particles. Extracellular osmolytes were found to have an effect on the efficiency of incorporation of fusion proteins into VLPs in Escherichia coli when a carbenicillin, but not a kanamycin, selection marker was used. The addition of sucrose to the growth medium decreased the incorporation efficiency; the osmoprotectant glycine betaine eliminated this effect. The decrease in efficiency was not observed when carbenicillin was omitted from the final expression culture. The addition of sodium chloride instead of sucrose gave rise to particles with a larger number of fusion proteins than the standard conditions. These results illustrate that cellular conditions should be taken into account even in apparently simple systems when natural or engineered protein nanoparticles are made.
Co-reporter:Vu Hong;StanislavI. Presolski;Celia Ma ;M.G. Finn
Angewandte Chemie International Edition 2009 Volume 48( Issue 52) pp:9879-9883
Publication Date(Web):
DOI:10.1002/anie.200905087
Co-reporter:Vu Hong;StanislavI. Presolski;Celia Ma ;M.G. Finn
Angewandte Chemie 2009 Volume 121( Issue 52) pp:10063-10067
Publication Date(Web):
DOI:10.1002/ange.200905087
Co-reporter:Andrew K. Udit Dr.;Chris Everett;Andrew J. Gale ;Jennifer Reiber Kyle;Mihri Ozkan
ChemBioChem 2009 Volume 10( Issue 3) pp:503-510
Publication Date(Web):
DOI:10.1002/cbic.200800493
Co-reporter:Duane E. Prasuhn Jr., Jane Kuzelka, Erica Strable, Andrew K. Udit, So-Hye Cho, Gabriel C. Lander, Joel D. Quispe, James R. Diers, David F. Bocian, Clint Potter, Bridget Carragher, M.G. Finn
Chemistry & Biology 2008 Volume 15(Issue 5) pp:513-519
Publication Date(Web):19 May 2008
DOI:10.1016/j.chembiol.2008.03.018
The addition of a hexahistidine tag to the N terminus of the hepatitis B capsid protein gives rise to a self-assembled particle with 80 sites of high local density of histidine side chains. Iron protoporphyrin IX has been found to bind tightly at each of these sites, making a polyvalent system of well-defined spacing between metalloporphyrin complexes. The spectroscopic and redox properties of the resulting particle are consistent with the presence of 80 site-isolated bis(histidine)-bound heme centers, comprising a polyvalent b-type cytochrome mimic.
Co-reporter:Erica Strable, Duane E. Prasuhn Jr., Andrew K. Udit, Steven Brown, A. James Link, John T. Ngo, Gabriel Lander, Joel Quispe, Clinton S. Potter, Bridget Carragher, David A. Tirrell and M. G. Finn
Bioconjugate Chemistry 2008 Volume 19(Issue 4) pp:866
Publication Date(Web):March 5, 2008
DOI:10.1021/bc700390r
Virus-like particles composed of hepatitis B virus (HBV) or bacteriophage Qβ capsid proteins have been labeled with azide- or alkyne-containing unnatural amino acids by expression in a methionine auxotrophic strain of E. coli. The substitution does not affect the ability of the particles to self-assemble into icosahedral structures indistinguishable from native forms. The azide and alkyne groups were addressed by Cu(I)-catalyzed [3 + 2] cycloaddition: HBV particles were decomposed by the formation of more than 120 triazole linkages per capsid in a location-dependent manner, whereas Qβ suffered no such instability. The marriage of these well-known techniques of sense-codon reassignment and bioorthogonal chemical coupling provides the capability to construct polyvalent particles displaying a wide variety of functional groups with near-perfect control of spacing.
Co-reporter:Adeline Miermont;Hannah Barnhill;Erica Strable;Xiaowei Lu;Katherine A. Wall Dr.;Qian Wang Dr.;M.G. Finn Dr.;Xuefei Huang Dr.
Chemistry - A European Journal 2008 Volume 14( Issue 16) pp:4939-4947
Publication Date(Web):
DOI:10.1002/chem.200800203
Abstract
Immunotherapy targeting tumor cell surface carbohydrates is a promising approach for cancer treatment. However, the low immunogenecity of carbohydrates presents a formidable challenge. We describe here the enhancement of carbohydrate immunogenicity by an ordered display on the surface of the cowpea mosaic virus (CPMV) capsid. The Tn glycan, which is overexpressed on numerous cancer cell surfaces, was selected as the model antigen for our study. Previously it has been shown that it is difficult to induce a strong T cell-dependent immune response against the monomeric form of Tn presented in several ways on different carriers. In this study, we first synthesized Tn antigens derivatized with either a maleimide or a bromoacetamide moiety that was conjugated selectively to a cysteine mutant of CPMV. The glycoconjugate was then injected into mice and pre- and post-immune antibody levels in the mice sera were measured by enzyme-linked immunosorbant assays. High total antibody titers and, more importantly, high IgG titers specific for Tn were obtained in the post-immune day 35 serum, suggesting the induction of T cell-dependent antibody isotype switching by the glycoconjugate. The antibodies generated were able to recognize Tn antigens presented in their native conformations on the surfaces of both MCF-7 breast cancer cells and the multidrug resistant breast cancer cell line NCI-ADR RES. These results suggest that the CPMV capsid can greatly enhance the immunogenicity of weak antigens such as Tn and this can provide a promising tool for the development of carbohydrate based anti-cancer vaccines.
Co-reporter:Vu Hong;Andrew K. Udit Dr.;Richard A. Evans
ChemBioChem 2008 Volume 9( Issue 9) pp:1481-1486
Publication Date(Web):
DOI:10.1002/cbic.200700768
Abstract
The copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) reaction has found broad application in myriad fields. For the most demanding applications that require high yields at low substrate concentrations, highly active but air-sensitive copper complexes must be used. We describe here the use of an electrochemical potential to maintain catalysts in the active CuI oxidation state in the presence of air. This simple procedure efficiently achieves excellent yields of CuAAC products from both small-molecule and protein substrates without the use of potentially damaging chemical reducing agents. A new water-soluble carboxylated version of the popular tris(benzyltriazolylmethyl)amine (TBTA) ligand is also described. Cyclic voltammetry revealed reversible or quasi-reversible electrochemical redox behavior of copper complexes of the TBTA derivative (2; E1/2=60 mV vs. Ag/AgCl), sulfonated bathophenanthroline (3; E1/2=−60 mV), and sulfonated tris(benzimidazoylmethyl)amine (4; E1/2≈−70 mV), and showed catalytic turnover to be rapid relative to the voltammetry time scale. Under the influence of a −200 mV potential that was established by using a reticulated vitreous carbon working electrode, CuSO4 and 3 formed a superior catalyst. Electrochemically protected bioconjugations in air were performed by using bacteriophage Qβ that was derivatized with azide moieties at surface lysine residues. Complete derivatization of more than 600 reactive sites per particle was demonstrated within 12 h of electrolysis with substoichiometric quantities of Cu⋅3.
Co-reporter:Duane E. Prasuhn, Jr., Robert M. Yeh, Andre Obenaus, Marianne Manchester and M. G. Finn
Chemical Communications 2007 (Issue 12) pp:1269-1271
Publication Date(Web):15 Jan 2007
DOI:10.1039/B615084E
Icosahedral virus particles decorated with a Gd(DOTA) analogue by Cu-mediated azide–alkyne cycloaddition (CuAAC) and/or with Gd3+ ions by coordination to the viral nucleoprotein show increased T1 relaxivity relative to free Gd(DOTA) complexes in solution.
Co-reporter:Pratik Singh, Duane Prasuhn, Robert M. Yeh, Giuseppe Destito, Chris S. Rae, Kent Osborn, M.G. Finn, Marianne Manchester
Journal of Controlled Release 2007 Volume 120(1–2) pp:41-50
Publication Date(Web):13 July 2007
DOI:10.1016/j.jconrel.2007.04.003
Virus-based nanoparticles (VNPs) from a variety of sources are being developed for biomedical and nanotechnology applications that include tissue targeting and drug delivery. However, the fate of most of those particles in vivo has not been investigated. Cowpea mosaic virus (CPMV), a plant comovirus, has been found to be amenable to the attachment of a variety of molecules to its coat protein, as well as to modification of the coat protein sequence by genetic means. We report here the results of studies of the bio-distribution, toxicology, and pathology of CPMV in mice. Plasma clearance and tissue biodistribution were measured using CPMV particles derivatized with lanthanide metal complexes. CPMV particles were cleared rapidly from plasma, falling to undetectable levels within 20 min. By 30 min the majority of the injected VNPs were trapped in the liver and to a lesser extent the spleen with undetectable amounts in other tissues. At doses of 1 mg, 10 mg and 100 mg per kg body weight, no toxicity was noted and the mice appeared to be normal. Hematology was essentially normal, although with the highest dose examined, the mice were somewhat leukopenic with relative decreases in both neutrophils and lymphocytes. Histological examination of the spleen showed cellular infiltration, which upon flow cytometry analyses revealed elevated B lymphocytes on the first day following virus administration that subsequently subsided. Microscopic evaluation of various other tissues revealed a lack of apparent tissue degeneration or necrosis. Overall, CPMV appears to be a safe and non-toxic platform for in vivo biomedical applications.
Co-reporter:Giuseppe Destito, Robert Yeh, Chris S. Rae, M.G. Finn, Marianne Manchester
Chemistry & Biology 2007 Volume 14(Issue 10) pp:1152-1162
Publication Date(Web):26 October 2007
DOI:10.1016/j.chembiol.2007.08.015
Cowpea mosaic virus (CPMV) is a well-characterized nanoparticle that has been used for a variety of nanobiotechnology applications. CPMV interacts with several mammalian cell lines and tissues in vivo. To overcome natural CPMV targeting and redirect CPMV particles to cells of interest, we attached a folic acid-PEG conjugate by using the copper-catalyzed azide-alkyne cycloaddition reaction. PEGylation of CPMV completely eliminated background binding of the virus to tumor cells. The PEG-folate moiety allowed CPMV-specific recognition of tumor cells bearing the folate receptor. In addition, by testing CPMV formulations with different amounts of the PEG-FA moiety displayed on the surface, we show that higher-density loading of targeting ligands on CPMV may not be necessary for efficient targeting to tumor cells. These studies help to define the requirements for efficiently targeting nanoparticles and protein cages to tumors.
Co-reporter:Eiton Kaltgrad;Sayam Sen Gupta Dr.;Sreenivas Punna Dr.;Cheng-Yuan Huang;Aileen Chang Dr.;Chi-Huey Wong ;Ola Blixt
ChemBioChem 2007 Volume 8(Issue 12) pp:
Publication Date(Web):6 AUG 2007
DOI:10.1002/cbic.200700225
Tetra- and hexasaccharides were arrayed on the exterior surface of cowpea mosaic virus by using a copper-catalyzed azide–alkyne cycloaddition reaction. Inoculation of chickens with these virus conjugates gave rise to large quantities of polyclonal anti-glycan IgY antibodies that displayed excellent avidity and specificity on analysis with printed glycan microarrays. Avian IgY antibodies are produced in significantly higher yield than is possible for mouse or rabbit IgG, and exhibit reduced cross reactivity with native mammalian proteins. For a tri-LacNAc antigen, affinity purification against immobilized mono-LacNAc was necessary to provide a set of antibodies with specific binding properties. Comparable performance was observed for the virus-based polyclonal versus a commercial monoclonal antibody raised against the globo-H tetrasaccharide; this highlights the utility of the glycan microarray for both quality control and rapid in-depth analysis. Virus–carbohydrate conjugates are promising candidates for development in diagnostic and immunotherapeutic applications.
Co-reporter:David D. Díaz;Yi Liu;K. Barry Sharpless;Adrian A. Accurso;Valery V. Fokin
Journal of Polymer Science Part A: Polymer Chemistry 2007 Volume 45(Issue 22) pp:5182-5189
Publication Date(Web):1 OCT 2007
DOI:10.1002/pola.22262
1,2,3-Triazole-based polymers generated from the Cu(I)-catalyzed cycloaddition between multivalent azides and acetylenes are effective adhesive materials for metal surfaces. The adhesive capacities of candidate mixtures of azide and alkyne components were measured by a modified peel test, using a customized adhesive tester. A particularly effective tetravalent alkyne and trivalent azide combination was identified, giving exceptional strength that matches or exceeds the best commercial formulations. The addition of Cu catalyst was found to be important for the synthesis of stronger adhesive polymers when cured at room temperature. Heating also accelerated curing rates, but the maximum adhesive strengths achieved at both room temperature and high temperature were the same, suggesting that crosslinking reaches the same advanced point in all cases. Polytriazoles also form adhesives to aluminum, but copper is bound more effectively, presumably because active Cu(I) ions may be leached from the surface to promote crosslinking and adhesion. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5182–5189, 2007
Co-reporter:David D. Díaz;Sayam Sen Gupta;Jane Kuzelka;Marcin Cymborowski;Michal Sabat
European Journal of Inorganic Chemistry 2006 Volume 2006(Issue 22) pp:
Publication Date(Web):5 OCT 2006
DOI:10.1002/ejic.200600686
A novel chelating chiral bis(formamidine–urea) ligand was synthesized and used to prepare the corresponding NiII and CuII complexes. Spectroscopic and X-ray crystallographic analysis of the former revealed that the urea moiety of the acyclic tetradentate ligand is deprotonated and binds to the square-planar Ni2+ ion through amide nitrogen atoms. This complex showed quasi-reversible redox behavior in cyclic voltammetry, with E1/2 = 640 mV vs. Cp2Fe+/Cp2Fe corresponding to the NiIII/NiII couple. The Cu complex was shown by EPR spectroscopy to also adopt a square-planar geometry [g∥ = 2.25 (A∥ = 184 G), g⟂ = 2.06 at 6 K], and reduction was found to be irreversible, perhaps due to the rigid nature of the tetradentate ligand. The nickel complex was found to be a modestly active catalyst for epoxidation of electron-richalkenes under Mukaiyama’s conditions, likely involving a radical mechanism. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Co-reporter:Chunmei Li
Journal of Polymer Science Part A: Polymer Chemistry 2006 Volume 44(Issue 19) pp:5513-5518
Publication Date(Web):21 AUG 2006
DOI:10.1002/pola.21623
A highly crosslinked hyperbranched polymer that rapidly swells and shrinks in a halogenated solvent in response to the addition of an acid or base has been prepared by Cu(I) catalysis of the reaction between a diazide and an amine-containing trialkyne. The triazole linkages in the polymer are highly stable and may also play a role in the swelling behavior. The swelling–deswelling process is reversible. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5513–5518, 2006
Co-reporter:Sayam Sen Gupta, Krishnaswami S. Raja, Eiton Kaltgrad, Erica Strable and M. G. Finn
Chemical Communications 2005 (Issue 34) pp:4315-4317
Publication Date(Web):19 Jul 2005
DOI:10.1039/B502444G
The CuI-catalyzed ATRP and azide–alkyne cycloaddition reactions together provide a versatile method for the synthesis of end-functionalized glycopolymers and their attachment to a suitably modified viral protein scaffold.
Co-reporter:Valentin O. Rodionov;Valery V. Fokin
Angewandte Chemie International Edition 2005 Volume 44(Issue 15) pp:
Publication Date(Web):3 FEB 2005
DOI:10.1002/anie.200461496
A powerful engine: The Cu-catalyzed azide–alkyne cycloaddition depends on rapid formation of CuI–acetylide complexes from terminal alkynes 2 and their ability to activate organic azides 1. A kinetics study uncovered a bimolecular dependence on the metal and an unusually fast intramolecular variant of the process. The results suggest the importance of 3 as a reactive intermediate.
Co-reporter:Sreenivas Punna Dr.;Jane Kuzelka Dr.;Qian Wang Dr.
Angewandte Chemie International Edition 2005 Volume 44(Issue 15) pp:
Publication Date(Web):3 FEB 2005
DOI:10.1002/anie.200461656
Rings forged with copper: Oligopeptide cyclodimerization occurs selectively when precursors containing azide and alkyne groups are exposed to copper(I) ions on polystyrene supports (see picture; Prot=protecting group).
Co-reporter:Valentin O. Rodionov;Valery V. Fokin
Angewandte Chemie 2005 Volume 117(Issue 15) pp:
Publication Date(Web):3 FEB 2005
DOI:10.1002/ange.200461496
Ein kräftiger Motor: Die Cu-katalysierte Azid-Alkin-Cycloaddition (siehe Schema) beruht auf der schnellen Bildung von CuI-Acetylid-Komplexen aus terminalen Alkinen 2 und deren Fähigkeit zur Aktivierung organischer Azide 1. Eine kinetische Studie zu dieser Reaktion ergab eine bimolekulare Abhängigkeit vom Metall. Eine ungewöhnlich schnell verlaufende intramolekulare Variante lässt auf eine Kupfer-Triazol-Spezies 3 als reaktives Intermediat schließen.
Co-reporter:Sreenivas Punna Dr.;Jane Kuzelka Dr.;Qian Wang Dr.
Angewandte Chemie 2005 Volume 117(Issue 15) pp:
Publication Date(Web):3 FEB 2005
DOI:10.1002/ange.200461656
Ringe aus der Kupferschmiede: Auf Polystyrol verankerte Oligopeptide mit Azid- und Alkin-Endgruppen cyclodimerisieren selektiv in Gegenwart von Kupfer(I)-Ionen (siehe Schema; Prot=Schutzgruppe).
Co-reporter:David D. Díaz and M. G. Finn
Chemical Communications 2004 (Issue 21) pp:2514-2516
Publication Date(Web):22 Sep 2004
DOI:10.1039/B406704E
An improvement in the practical aspects of formamidine synthesis has resulted in the discovery of a class of compounds which produce organogels in protic solvents, presumably through intermolecular hydrogen bonding and π–π stacking interactions.
Co-reporter:Jun-cai Meng, Gary Siuzdak and M. G. Finn
Chemical Communications 2004 (Issue 18) pp:2108-2109
Publication Date(Web):05 Aug 2004
DOI:10.1039/B408200A
The development of chemically stable porous silicon (pSi) materials for DIOS (Desorption/Ionization on Silicon) mass spectrometry, covalent linkers cleaved in the DIOS laser pulse, and efficient methods for bond formation to immobilized species, allows for on-chip affinity purification and mass detection.
Co-reporter:David D. Díaz;Sreenivas Punna;Philipp Holzer;Andrew K. McPherson;K. Barry Sharpless;Valery V. Fokin
Journal of Polymer Science Part A: Polymer Chemistry 2004 Volume 42(Issue 17) pp:4392-4403
Publication Date(Web):28 JUL 2004
DOI:10.1002/pola.20330
The copper(I)-catalyzed cycloaddition reaction between azides and alkynes has been employed to make metal-adhesive materials. Copper and brass surfaces supply the necessary catalytic Cu ions, and thus the polymerization process occurs selectively on these metals in the absence of added catalysts. Alternatively, copper compounds can be added to monomer mixtures and then introduced to reducing metal surfaces such as zinc to initiate polymerization. The resulting materials were found to possess comparable or superior adhesive strength to standard commercial glues, and structure-activity correlations have identified several important properties of the monomers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4392–4403, 2004
Co-reporter:Jun-Cai Meng Dr.;Claudia Averbuj Dr.;Warren G. Lewis;Gary Siuzdak
Angewandte Chemie 2004 Volume 116(Issue 10) pp:
Publication Date(Web):25 FEB 2004
DOI:10.1002/ange.200352803
Dippen – waschen – analysieren: Moleküle können durch Diels-Alder-Reaktionen an maßgeschneiderte poröse Silicium-Wafer geknüpft und mit dem Laserpuls eines MALDI-Massenspektrometers positionscodiert effizient abgelöst und detektiert werden (siehe Schema).
Co-reporter:Jun-Cai Meng Dr.;Claudia Averbuj Dr.;Warren G. Lewis;Gary Siuzdak
Angewandte Chemie International Edition 2004 Volume 43(Issue 10) pp:
Publication Date(Web):25 FEB 2004
DOI:10.1002/anie.200352803
Dip, wash, and analyze: Molecules can be attached to tailored porous silicon wafers by using Diels–Alder reactions and efficiently detached and detected in the laser pulse of a MALDI mass spectrometer in a positionally encoded manner (see scheme).
Co-reporter:David D. Díaz Dr.
Chemistry - A European Journal 2004 Volume 10(Issue 1) pp:
Publication Date(Web):19 DEC 2003
DOI:10.1002/chem.200305388
Formamidine urea compounds exchange imine fragments with primary nitrogen nucleophiles, allowing the preparation of a variety of derivatives from a single precursor. The reactivities of these species are governed primarily by the electron-donating power of the substituents and are tunable over a range of >103 in first-order rates of hydrolysis.
Co-reporter:Derek J. Taylor, Qian Wang, Brian Bothner, Padmaja Natarajan, M. G. Finn and John E. Johnson
Chemical Communications 2003 (Issue 22) pp:2770-2771
Publication Date(Web):15 Oct 2003
DOI:10.1039/B310533D
Nudaurelia capensis ω virus, which undergoes one of the largest known structural changes of icosahedral viruses in response to its environment, exhibits chemical reactivity which depends on its conformational state.
Co-reporter:Krishnaswami S. Raja Dr.;Qian Wang Dr.
ChemBioChem 2003 Volume 4(Issue 12) pp:
Publication Date(Web):24 NOV 2003
DOI:10.1002/cbic.200300759
Sugar-coated viruses behave as large dendrimeric poly(carbohydrates). Readily prepared from the icosahedral cowpea mosaic virus (one-twelfth of the structure of this scaffold is shown here, with attachment points in yellow) and electrophilic sugar derivatives, the resulting particles bind strongly to the lectin concanavalin-A, forming cross-linked networks. Measurements of binding strength demonstrate effective polyvalencies comparable to the most potent dendrimer- and polymer-based systems reported to date, with the added advantage of near atomic-resolution control over structure.
Co-reporter:Warren G. Lewis;Luke G. Green Dr.;Flavio Grynszpan ;Zoran Radić Dr.;Paul R. Carlier ;Palmer Taylor ;K. Barry Sharpless
Angewandte Chemie International Edition 2002 Volume 41(Issue 6) pp:
Publication Date(Web):15 MAR 2002
DOI:10.1002/1521-3773(20020315)41:6<875::AID-ANIE875>3.0.CO;2-Y
The cover picture shows the electric eel, Electrophorus electricus, a source for commercially available acetylcholinesterase. In an experiment described by K. B. Sharpless and M. G. Finn and co-workers on pp. 1053–1057, a femtomolar inhibitor was assembled by the enzyme from a collection of building blocks containing azide and alkyne functional groups, shown floating in solution. The templated 1,3-dipolar cycloaddition reaction, producing the inhibitor, is represented by the flare of light at the center of the image.
Co-reporter:Warren G. Lewis;Luke G. Green Dr.;Flavio Grynszpan ;Zoran Radić Dr.;Paul R. Carlier ;Palmer Taylor ;K. Barry Sharpless
Angewandte Chemie International Edition 2002 Volume 41(Issue 6) pp:
Publication Date(Web):15 MAR 2002
DOI:10.1002/1521-3773(20020315)41:6<1053::AID-ANIE1053>3.0.CO;2-4
Form-fitting chemistry in a protein mold is enabled by the use of the 1,3-dipolar cycloaddition of azides and alkynes. The enzyme acetylcholinesterase preferentially assembles one pair of these reactants, each of which bears a group that binds to adjacent positions on the protein structure (see picture), into a 1,2,3-triazole adduct that is the most potent noncovalent inhibitor of the enzyme yet developed.
Co-reporter:Qian Wang Dr.;Tianwei Lin ;Liang Tang Dr.;John E. Johnson
Angewandte Chemie International Edition 2002 Volume 41(Issue 3) pp:
Publication Date(Web):29 JAN 2002
DOI:10.1002/1521-3773(20020201)41:3<459::AID-ANIE459>3.0.CO;2-O
Grow your nanochemical dendrimers! Cowpea mosaic virus (see relief image derived from the X-ray structure) can be isolated from its host plant in gram quantities and participates in selective chemical reactions at specific sites of the icosahedrally-arrayed coat protein. Mutant structures can be easily engineered, propagated, and isolated to provide particles with tailored reactivities. Applications for these particles in areas from catalysis to materials science can be conceived.
Co-reporter:M.G. Finn
Chirality 2002 Volume 14(Issue 7) pp:534-540
Publication Date(Web):7 JUN 2002
DOI:10.1002/chir.10101
Methods for enantiomeric excess determination using a variety of spectroscopic techniques are summarized. Particular attention is paid to techniques that have promise for application to problems of combinatorial catalyst discovery but have not yet been so employed. Chirality 14:534–540, 2002. © 2002 Wiley-Liss, Inc.
Co-reporter:Warren G. Lewis;Luke G. Green Dr.;Flavio Grynszpan ;Zoran Radić Dr.;Paul R. Carlier ;Palmer Taylor ;K. Barry Sharpless
Angewandte Chemie 2002 Volume 114(Issue 6) pp:
Publication Date(Web):15 MAR 2002
DOI:10.1002/1521-3757(20020315)114:6<915::AID-ANGE915>3.0.CO;2-3
Das Titelbild zeigt den Zitteraal Electrophorus electricus – eine reichhaltige, kommerziell genutzte Quelle für Acetylcholinesterase. In einem Experiment, das K. B. Sharpless und M. G. Finn et al. auf S. 1095 ff. beschreiben, wurde mithilfe dieses Enzyms aus einer Reihe von Synthesebausteinen mit Azid- und Alkin-Einheiten (in Lösung schwimmend dargestellt) ein in femtomolaren Konzentrationen wirksamer Inhibitor erhalten. Die Templatreaktion, durch die der Inhibitor gebildet wird – eine 1,3-dipolare Cycloaddition –, findet an der hell hervorgehobenen Stelle im Enzym (Bildmitte) statt.
Co-reporter:Warren G. Lewis;Luke G. Green Dr.;Flavio Grynszpan ;Zoran Radić Dr.;Paul R. Carlier ;Palmer Taylor ;K. Barry Sharpless
Angewandte Chemie 2002 Volume 114(Issue 6) pp:
Publication Date(Web):15 MAR 2002
DOI:10.1002/1521-3757(20020315)114:6<1095::AID-ANGE1095>3.0.CO;2-3
Maßgeschneiderte Chemie in einer Protein-Vorlage: Bei einer Reihe von Aziden und Alkinen, Reaktanten für eine 1,3-dipolare Cycloaddition, wird vom Enzym Acetylcholinesterase bevorzugt ein Paar von Reaktionspartnern umgesetzt, von denen beide an benachbarten Stellen in der Proteinstruktur binden (siehe Bild). Das dabei gebildete 1,2,3-Triazol ist der stärkste bisher entwickelte nichtkovalent gebundene Inhibitor für dieses Enzym.
Co-reporter:Qian Wang Dr.;Tianwei Lin ;Liang Tang Dr.;John E. Johnson
Angewandte Chemie 2002 Volume 114(Issue 3) pp:
Publication Date(Web):29 JAN 2002
DOI:10.1002/1521-3757(20020201)114:3<477::AID-ANGE477>3.0.CO;2-2
Dendrimere aus der Pflanzenzuchtanstalt? Das Kuherbsen-Mosaikvirus (das gezeigte Bild wurde aus Kristallstrukturdaten generiert) kann aus besagten Erbsen in Grammmengen isoliert und für selektive chemische Reaktionen an spezifischen Stellen des ikosaedrisch strukturierten Hüllproteins eingesetzt werden; Mutanten lassen sich zu Partikeln mit maßgeschneiderter Reaktivität umfunktionieren. Anwendungsmöglichkeiten für diese Partikel, die auch als großer Dendrimerkern eingesetzt werden könnten, erstrecken sich von der Katalyse bis zu den Materialwissenschaften.
Co-reporter:Qian Wang Dr.;Tianwei Lin ;Liang Tang Dr.;John E. Johnson
Angewandte Chemie International Edition 2002 Volume 41(Issue 3) pp:
Publication Date(Web):29 JAN 2002
DOI:10.1002/1521-3773(20020201)41:3<371::AID-ANIE371>3.0.CO;2-F
The cover picture shows a cowpea plant heavily infected with cowpea mosaic virus (background). A simple isolation procedure provides high yields of pure virus, which can be derivatized selectively by chemical reagents. The particles therefore behave in many respects like prefabricated dendrimers on a nanochemical (30 nm diameter) scale. Their polyvalency is highlighted by the foreground image, showing a cryo-electron microscopy analysis of the virus bearing gold clusters at each of 60 reactive cysteine residues introduced by site-directed mutagenesis. Further details are reported by J. E. Johnson and M. G. Finn and co-workers on p. 459ff.
Co-reporter:Qian Wang Dr.;Tianwei Lin ;Liang Tang Dr.;John E. Johnson
Angewandte Chemie 2002 Volume 114(Issue 3) pp:
Publication Date(Web):29 JAN 2002
DOI:10.1002/1521-3757(20020201)114:3<383::AID-ANGE383>3.0.CO;2-I
Das Titelbild zeigt im Hintergrund eine mit dem Kuherbsen-Mosaikvirus stark infizierte Kuherbsenpflanze. Eine einfache Isolierungsprozedur liefert hohe Ausbeuten des reinen Virus, das durch chemische Reagentien selektiv derivatisiert werden kann. Die nanometergroßen Partikel (Durchmesser 30 nm) verhalten sich aus diesem Grund in mehrfacher Hinsicht wie vorgefertigte Dendrimere. Ihre Polyvalenz ist durch das Bild im Vordergrund hervorgehoben. Es zeigt eine kryo-elektronenmikroskopische Analyse des Virus, das an jeder der durch ortsspezifische Mutagenese eingeführten reaktiven Cystein-Reste einen Goldcluster trägt. Über weitere Einzelheiten zu diesem Thema berichten J. E. Johnson und M. G. Finn et al. auf S. 477 ff.
Co-reporter:Zhouxin Shen;Sulan Yao;Gary Siuzdak;John E. Crowell
Israel Journal of Chemistry 2001 Volume 41(Issue 4) pp:313-316
Publication Date(Web):8 MAR 2010
DOI:10.1560/TBXU-FD8H-FHM1-NR8H
The determination of enantiomeric excess by kinetic resolution mass spectrometry has been implemented with the Desorption/Ionization On Silicon (DIOS) MS technique. Measurements can thereby be made much more rapidly than was previously possible, bringing this general methodology for screening asymmetric catalysts closer to true high-throughput status.
Co-reporter:Susan M. Maddock Dr.
Angewandte Chemie 2001 Volume 113(Issue 11) pp:
Publication Date(Web):28 MAY 2001
DOI:10.1002/1521-3757(20010601)113:11<2196::AID-ANGE2196>3.0.CO;2-I
Konjugation erforderlich: Die Umsetzung von Zinnhydriden zu Distannanen und Diwasserstoff lässt sich durch Allenylidenruthenium-Komplexe katalysieren (siehe Schema). Alkinyl- oder Alkenylgruppen als Reste R, die in Konjugation mit dem Arenring stehen, sind für die katalytische Aktivität notwendig – ein ungewöhnliches Beispiel für die Kontrolle der Reaktivität eines Metallzentrums durch einen entfernten Substituenten.
Co-reporter:Jianhua Guo;Jiangyue Wu;Gary Siuzdak
Angewandte Chemie 1999 Volume 111(Issue 12) pp:
Publication Date(Web):8 JUN 1999
DOI:10.1002/(SICI)1521-3757(19990614)111:12<1868::AID-ANGE1868>3.0.CO;2-J
Eine neue Anwendung für die Massenspektrometrie: Die Enantiomerenüberschüsse sehr kleiner Mengen chiraler Alkohole und Amine können über eine Derivatisierung mit chiralen Acylierungsmitteln auf elegante Weise bestimmt werden. Grundlage dieser neuen Methode ist die Beobachtung, daß die Masse der dabei entstehenden Ester bzw. Amide mit ihrer absoluten Konfiguration korreliert; sie können daher leicht durch Elektrospray-Ionisations-Massenspektrometrie (ESI-MS; siehe Schema) analysiert werden. Für diese Methode genügt überraschenderweise ein nur geringer Unterschied in der Diastereoselektivität beim Acylierungsschritt, sie ist daher allgemein anwendbar.
Co-reporter:Jianhua Guo;Jiangyue Wu;Gary Siuzdak
Angewandte Chemie International Edition 1999 Volume 38(Issue 12) pp:
Publication Date(Web):8 JUN 1999
DOI:10.1002/(SICI)1521-3773(19990614)38:12<1755::AID-ANIE1755>3.0.CO;2-Q
New applications for your mass spectrometer—use it to measure enantiomeric excess! The enantiomeric content of very small quantities of chiral alcohols and amines has been determined by derivatization with chiral acylating agents in which mass is correlated to absolute configuration. The resultant esters and amides were then analyzed by electrospray ionization mass spectrometry (ESI-MS; shown schematically). The technique requires surprisingly low levels of diastereoselectivity in the acylation step, and is therefore generally applicable.
Co-reporter:Duane E. Prasuhn, Jr., Robert M. Yeh, Andre Obenaus, Marianne Manchester and M. G. Finn
Chemical Communications 2007(Issue 12) pp:NaN1271-1271
Publication Date(Web):2007/01/15
DOI:10.1039/B615084E
Icosahedral virus particles decorated with a Gd(DOTA) analogue by Cu-mediated azide–alkyne cycloaddition (CuAAC) and/or with Gd3+ ions by coordination to the viral nucleoprotein show increased T1 relaxivity relative to free Gd(DOTA) complexes in solution.
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![Propanenitrile, 3,3'-[[2,2-bis[(2-cyanoethoxy)methyl]-1,3-propanediyl]bis(oxy)]bis-](/data/chemimg/16000/2465-91-0_b.png)
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