title: Solution structure of the C1-subdomain of Bacillus stearothermophilus translation initiation factor IF2.
abstract: IF2 is one of three bacterial translation initiation factors that are conserved through all kingdoms of life. It binds the 30S and 50S ribosomal subunits, as well as fMet-tRNAf(Met). After these interactions, fMet-tRNAf(Met) is oriented to the ribosomal P-site where the first amino acid of the nascent polypeptide, formylmethionine, is presented. The C-terminal domain of Bacillus stearothermophilus IF2, which is responsible for recognition and binding of fMet-tRNAf(Met), contains two structured modules. Previously, the solution structure of the most C-terminal module, IF2-C2, has been elucidated by NMR spectroscopy and direct interactions between this subdomain and fMet-tRNAf(Met) were reported. In the present NMR study we have obtained the spectral assignment of the other module of the C-terminal domain (IF2-C1) and determined its solution structure and backbone dynamics. The IF2-C1 core forms a flattened fold consisting of a central four-stranded parallel beta-sheet flanked by three alpha-helices. Although its overall organization resembles that of subdomain III of the archaeal IF2-homolog eIF5B whose crystal structure had previously been reported, some differences of potential functional significance are evident.
authors.affiliation: Bijvoet Center for Biomolecular Research, Department of NMR Spectroscopy, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
authors.forename: Hans
authors.initials: H
authors.lastname: Wienk
authors.forename: Simona
authors.initials: S
authors.lastname: Tomaselli
authors.forename: Cédric
authors.initials: C
authors.lastname: Bernard
authors.forename: Roberto
authors.initials: R
authors.lastname: Spurio
authors.forename: Delia
authors.initials: D
authors.lastname: Picone
authors.forename: Claudio O
authors.initials: CO
authors.lastname: Gualerzi
authors.forename: Rolf
authors.initials: R
authors.lastname: Boelens
mesh_terms: D015852:Eukaryotic Initiation Factor-2 / Q000737:chemistry* / Q000378:metabolism; D001411:Geobacillus stearothermophilus / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D010448:Peptide Initiation Factors / Q000737:chemistry; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D012996:Solutions; D040681:Structural Homology, Protein
chemical_list: D015852:Eukaryotic Initiation Factor-2; C118735:IF2 protein, archaeal; D010448:Peptide Initiation Factors; D012996:Solutions