The protein Etp1 of Schizosaccharomyces pombe consists of an amino-terminal COX15-like domain and a carboxy-terminal ferredoxin-like domain, Etp1fd, which is cleaved off after mitochondrial import. The physiological function of Etp1fd is supposed to lie in the participation in the assembly of iron–sulfur clusters and the synthesis of heme A. In addition, the protein was shown to be the first microbial ferredoxin being able to support electron transfer in mitochondrial steroid hydroxylating cytochrome P450 systems in vivo and in vitro, replacing thereby the native redox partner, adrenodoxin. Despite a sequence similarity of 39% and the fact that fission yeast is a mesophilic organism, thermodynamic studies revealed that Etp1fd has a melting temperature more than 20 °C higher than adrenodoxin. The three-dimensional structure of Etp1fd has been determined by crystallography. To the best of our knowledge it represents the first three-dimensional structure of a yeast ferredoxin. The structure-based sequence alignment of Etp1fd with adrenodoxin yields a rational explanation for their observed mutual exchangeability in the cytochrome P450 system. Analysis of the electron exchange with the S. pombe redox partner Arh1 revealed differences between Etp1fd and adrenodoxin, which might be linked to their different physiological functions in the mitochondria of mammals and yeast.The crystal structure of S. pombe Etp1fd, a ferredoxin involved in the mitochondrial assembly of iron–sulfur clusters, is presented. We describe the structural, thermodynamic and functional properties of Etp1fd in comparison with bovine Adx, a ferredoxin active in mitochondrial P450 systems.

The KorB protein of the broad-host-range plasmid RP4 acts as a multifunctional regulator of plasmid housekeeping genes, including those responsible for replication, maintenance and conjugation. Additionally, KorB functions as the ParB analog of the plasmid's partitioning system. The protein structure consists of eight helices, two of which belong to a predicted helix-turn-helix motif. Each half-site of the palindromic operator DNA binds one copy of the protein in the major groove. As confirmed by mutagenesis, recognition specificity is based mainly on two side chain interactions outside the helix-turn-helix motif with two bases next to the central base pair of the 13-base pair operator sequence. The surface of the KorB DNA-binding domain mirrors the overall acidity of KorB, whereas DNA binding occurs via a basic interaction surface. We present a model of KorB, including the structure of its dimerization domain, and discuss its interactions with the highly basic ParA homolog IncC.

Structural genomics in Europe is slowly coming off the ground. So far, European Commission funding is restricted to methods development projects, whereas structural genomics programs are funded from national sources. The research outlook is more toward techniques for high-throughput structure analysis than toward a systematic coverage of protein fold space. At present, there is little European coordination of the structural genomics effort.