title: Structural model for the selenocysteine-specific elongation factor SelB.
abstract: A structural model was established for the N-terminal part of translation factor SelB which shares sequence similarity with EF-Tu, taking into account the coordinates of the EF-Tu 3D structure and the consensus of SelB sequences from four bacteria. The model showed that SelB is homologous in its N-terminal domains over all three domains of EF-Tu. The guanine nucleotide binding site and the residues involved in GTP hydrolysis are similar to those of EF-Tu, but with some subtle differences possibly responsible for the higher affinity of SelB for GTP compared to GDP. In accordance, the EF-Tu epitopes interacting with EF-Ts are lacking in SelB. Information on the formation of the selenocysteyl-binding pocket is presented. A phylogenetic comparison of the SelB domains homologous to EF-Tu with those from EF-Tu and initiation factor 2 indicated that SelB forms a separate class of translation factors.
authors.affiliation: Institut für Molekulare Biotechnologie eV, Jena, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Hilgenfeld
authors.forename: A
authors.initials: A
authors.lastname: Böck
authors.forename: R
authors.initials: R
authors.lastname: Wilting
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010444:Peptide Elongation Factor Tu / Q000737:chemistry; D010445:Peptide Elongation Factors / Q000737:chemistry; D010802:Phylogeny; D017433:Protein Structure, Secondary; D017279:Selenocysteine / Q000032:analysis*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D016963:Thermus thermophilus / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D010445:Peptide Elongation Factors; C061878:SelB protein, Bacteria; D017279:Selenocysteine; D010444:Peptide Elongation Factor Tu