title: Translation initiation factor IF2 of the myxobacterium Stigmatella aurantiaca: presence of a single species with an unusual N-terminal sequence.
abstract: The structural gene for translation initiation factor IF2 (infB) was isolated from the myxobacterium Stigmatella aurantiaca on a 5.18-kb BamHI genomic restriction fragment. The infB gene (ca. 3.16 kb) encodes a 1,054-residue polypeptide with extensive homology within its G domain and C terminus with the equivalent regions of IF2s from Escherichia coli, Bacillus subtilis, Bacillus stearothermophilus, and Streptococcus faecium. The N-terminal region does not display any significant homology to other known proteins. The S. aurantiaca infB gene encodes a single protein which cross-reacted with antiserum to E. coli IF2 and was able to complement an E. coli infB mutant. The S. aurantiaca IF2 is distinguished from all other IF2s by a sequence of 160 residues near the N terminus that has an unusual composition, made up essentially of alanine, proline, valine, and glutamic acid. Within this sequence, the pattern PXXXAP is repeated nine times. Complete deletion of this sequence did not affect the factor's function in initiation of translation and even increased its capacity to complement the E. coli infB mutant.
authors.affiliation: Institut de Biologie Moléculaire et d'Ingénierie Génétique, URA CNRS 1172, Université de Poitiers, France.
authors.forename: L
authors.initials: L
authors.lastname: Bremaud
authors.forename: S
authors.initials: S
authors.lastname: Laalami
authors.forename: B
authors.initials: B
authors.lastname: Derijard
authors.forename: Y
authors.initials: Y
authors.lastname: Cenatiempo
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D003429:Cross Reactions; D015870:Gene Expression; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D009231:Myxococcales / Q000235:genetics*; D010448:Peptide Initiation Factors / Q000235:genetics* / Q000276:immunology; D039881:Prokaryotic Initiation Factor-2; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
chemical_list: D010448:Peptide Initiation Factors; D039881:Prokaryotic Initiation Factor-2