title: A conserved proline switch on the ribosome facilitates the recruitment and binding of trGTPases.
abstract: When elongation factor G (EF-G) binds to the ribosome, it first makes contact with the C-terminal domain (CTD) of L12 before interacting with the N-terminal domain (NTD) of L11. Here we have identified a universally conserved residue, Pro22 of L11, that functions as a proline switch (PS22), as well as the corresponding center of peptidyl-prolyl cis-trans isomerase (PPIase) activity on EF-G that drives the cis-trans isomerization of PS22. Only the cis configuration of PS22 allows direct contact between the L11 NTD and the L12 CTD. Mutational analyses of both PS22 and the residues of the EF-G PPIase center reveal their function in translational GTPase (trGTPase) activity, protein synthesis and cell survival in Escherichia coli. Finally, we demonstrate that all known universal trGTPases contain an active PPIase center. Our observations suggest that the cis-trans isomerization of the L11 PS22 is a universal event required for an efficient turnover of trGTPases throughout the translation process.
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Fang
authors.initials: F
authors.lastname: Yang
authors.forename: Dejiu
authors.initials: D
authors.lastname: Zhang
authors.forename: Zhi
authors.initials: Z
authors.lastname: Chen
authors.forename: Rui-Ming
authors.initials: RM
authors.lastname: Xu
authors.forename: Knud H
authors.initials: KH
authors.lastname: Nierhaus
authors.forename: Weimin
authors.initials: W
authors.lastname: Gong
authors.forename: Yan
authors.initials: Y
authors.lastname: Qin
mesh_terms: D000595:Amino Acid Sequence; D017124:Conserved Sequence; D004926:Escherichia coli / Q000737:chemistry / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism*; D020558:GTP Phosphohydrolases / Q000737:chemistry / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D007536:Isomerism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020653:Peptide Elongation Factor G / Q000737:chemistry / Q000378:metabolism*; D019696:Peptidylprolyl Isomerase / Q000737:chemistry / Q000378:metabolism; D011392:Proline / Q000032:analysis / Q000378:metabolism*; D012270:Ribosomes / Q000737:chemistry / Q000378:metabolism*; D016415:Sequence Alignment
chemical_list: D029968:Escherichia coli Proteins; D020653:Peptide Elongation Factor G; D006160:Guanosine Triphosphate; D011392:Proline; D020558:GTP Phosphohydrolases; D019696:Peptidylprolyl Isomerase