Allosteric collaboration between elongation factor G and the ribosomal L1 stalk directs tRNA movements during translation.
Determining the mechanism by which tRNAs rapidly and precisely transit through the ribosomal A, P, and E sites during translation remains a major goal in the study of protein synthesis. Here, we report the real-time dynamics of the L1 stalk, a structural element of the large ribosomal subunit that is implicated in directing tRNA movements during translation. Within pretranslocation ribosomal complexes, the L1 stalk exists in a dynamic equilibrium between open and closed conformations. Binding of elongation factor G (EF-G) shifts this equilibrium toward the closed conformation through one of at least two distinct kinetic mechanisms, where the identity of the P-site tRNA dictates the kinetic route that is taken. Within posttranslocation complexes, L1 stalk dynamics are dependent on the presence and identity of the E-site tRNA. Collectively, our data demonstrate that EF-G and the L1 stalk allosterically collaborate to direct tRNA translocation from the P to the E sites, and suggest a model for the release of E-site tRNA.
Fei
Jingyi
J
Department of Chemistry, Columbia University, New York, NY 10027, USA.
Bronson
Jonathan E
JE
Hofman
Jake M
JM
Srinivas
Rathi L
RL
Wiggins
Chris H
CH
Gonzalez
Ruben L
RL
D000494:Allosteric Regulation; D000495:Allosteric Site; D055592:Biophysical Phenomena; D031541:Fluorescence Resonance Energy Transfer; D007700:Kinetics; D046911:Macromolecular Substances; D008958:Models, Molecular; D020653:Peptide Elongation Factor G / Q000737:chemistry* / Q000378:metabolism*; D014176:Protein Biosynthesis; D011487:Protein Conformation; D012343:RNA, Transfer / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D012269:Ribosomal Proteins / Q000737:chemistry* / Q000378:metabolism*; D012270:Ribosomes / Q000737:chemistry / Q000378:metabolism
D046911:Macromolecular Substances; D020653:Peptide Elongation Factor G; D012269:Ribosomal Proteins; C028546:ribosomal protein L1; D012343:RNA, Transfer