title: Crystal structure of 70S ribosome with both cognate tRNAs in the E and P sites representing an authentic elongation complex.
abstract: During the translation cycle, a cognate deacylated tRNA can only move together with the codon into the E site. We here present the first structure of a cognate tRNA bound to the ribosomal E site resulting from translocation by EF-G, in which an entire L1 stalk (L1 protein and L1 rRNA) interacts with E-site tRNA (E-tRNA), representing an authentic ribosome elongation complex. Our results revealed that the Watson-Crick base pairing is formed at the first and second codon-anticodon positions in the E site in the ribosome elongation complex, whereas the codon-anticodon interaction in the third position is indirect. Analysis of the observed conformations of mRNA and E-tRNA suggests that the ribosome intrinsically has the potential to form codon-anticodon interaction in the E site, independently of the mRNA configuration. We also present a detailed description of the biologically relevant position of the entire L1 stalk and its interacting cognate E-tRNA, which provides a better understanding of the structural basis for translation elongation. Furthermore, to gain insight into translocation, we report the positioning of protein L6 contacting EF-G, as well as the conformational change of the C-terminal tail of protein S13 in the decoding center.
authors.affiliation: School of Biological Science, Nanyang Technological University, Singapore.
authors.forename: Shu
authors.initials: S
authors.lastname: Feng
authors.forename: Yun
authors.initials: Y
authors.lastname: Chen
authors.forename: Yong-Gui
authors.initials: YG
authors.lastname: Gao
mesh_terms: D003062:Codon; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism; D009690:Nucleic Acid Conformation; D010441:Peptide Chain Elongation, Translational / Q000502:physiology*; D010445:Peptide Elongation Factors / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D012333:RNA, Messenger / Q000737:chemistry / Q000378:metabolism; D012343:RNA, Transfer / Q000737:chemistry* / Q000378:metabolism; D054657:Ribosome Subunits / Q000737:chemistry* / Q000378:metabolism
chemical_list: D003062:Codon; D046912:Multiprotein Complexes; D010445:Peptide Elongation Factors; D012333:RNA, Messenger; D012343:RNA, Transfer