title: X-ray crystallography shows that translational initiation factor IF3 consists of two compact alpha/beta domains linked by an alpha-helix.
abstract: The structures of the two domains of translational initiation factor IF3 from Bacillus stearothermophilus have been solved by X-ray crystallography using single wavelength anomalous scattering and multiwavelength anomalous diffraction. Each of the two domains has an alpha/beta topology, with an exposed beta-sheet that is reminiscent of several ribosomal and other RNA binding proteins. An alpha-helix that protrudes out from the body of the N-terminal domain towards the C-terminal domain suggests that IF3 consists of two RNA binding domains connected by an alpha-helix and that it may bridge two regions of the ribosome. This represents the first high resolution structural information on a translational initiation factor.
authors.affiliation: Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
authors.forename: V
authors.initials: V
authors.lastname: Biou
authors.forename: F
authors.initials: F
authors.lastname: Shu
authors.forename: V
authors.initials: V
authors.lastname: Ramakrishnan
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D039621:Eukaryotic Initiation Factor-3; D001411:Geobacillus stearothermophilus / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D010448:Peptide Initiation Factors / Q000737:chemistry* / Q000235:genetics; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D012697:Serine Endopeptidases
chemical_list: D001426:Bacterial Proteins; D039621:Eukaryotic Initiation Factor-3; D010446:Peptide Fragments; D010448:Peptide Initiation Factors; D012697:Serine Endopeptidases; C057840:omptin outer membrane protease