title: Initiation of mRNA translation in bacteria: structural and dynamic aspects.
abstract: Initiation of mRNA translation is a major checkpoint for regulating level and fidelity of protein synthesis. Being rate limiting in protein synthesis, translation initiation also represents the target of many post-transcriptional mechanisms regulating gene expression. The process begins with the formation of an unstable 30S pre-initiation complex (30S pre-IC) containing initiation factors (IFs) IF1, IF2 and IF3, the translation initiation region of an mRNA and initiator fMet-tRNA whose codon and anticodon pair in the P-site following a first-order rearrangement of the 30S pre-IC produces a locked 30S initiation complex (30SIC); this is docked by the 50S subunit to form a 70S complex that, following several conformational changes, positional readjustments of its ligands and ejection of the IFs, becomes a 70S initiation complex productive in initiation dipeptide formation. The first EF-G-dependent translocation marks the beginning of the elongation phase of translation. Here, we review structural, mechanistic and dynamical aspects of this process.
authors.affiliation: Laboratory of Genetics, University of Camerino, 62032, Camerino, Italy. claudio.gualerzi@unicam.it.
authors.forename: Claudio O
authors.initials: CO
authors.lastname: Gualerzi
authors.affiliation: Laboratory of Genetics, University of Camerino, 62032, Camerino, Italy. cynthia.pon@unicam.it.
authors.forename: Cynthia L
authors.initials: CL
authors.lastname: Pon
mesh_terms: D001419:Bacteria / Q000235:genetics* / Q000378:metabolism; D001665:Binding Sites / Q000235:genetics; D018387:Codon, Initiator / Q000235:genetics / Q000378:metabolism; D008957:Models, Genetic; D009690:Nucleic Acid Conformation; D010448:Peptide Initiation Factors / Q000235:genetics / Q000378:metabolism; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012358:RNA, Transfer, Met / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism
chemical_list: D018387:Codon, Initiator; D010448:Peptide Initiation Factors; D012333:RNA, Messenger; D012358:RNA, Transfer, Met; C024988:tRNA, formylmethionine-
keywords: GTP; Protein synthesis; Translation initiation factors; fMet-tRNA; mRNA initiation region