Intermediate states during mRNA-tRNA translocation.
Recent studies support the notion that the pre-translocation (PRE) ribosomal complex functions, at least in part, as a Brownian machine, stochastically fluctuating among multiple conformations and transfer RNA (tRNA) binding configurations. Apart from the relatively more energetically stable conformational states of the PRE complex, termed macrostate I (MS I) and macrostate II (MS II), several additional intermediate states have been recently discovered. Structural and kinetic analyses of these states, made possible by cryogenic-electron microscopy (cryo-EM), X-ray crystallography, and single-molecule fluorescence resonance energy transfer (smFRET), have provided important insights into the translocation process, which is now understood to proceed, at least in the first step of the process, as a Brownian machine that is transiently stabilized in the 'productive' MS II conformation by the binding of the translocase elongation factor G (EF-G).
Howard Hughes Medical Institute, Department of Biochemistry and Molecular Biophysics, Columbia University, 650 W. 168th Street, New York, NY 10032, United States. jf2192@columbia.edu
Joachim
J
Frank
D009068:Movement; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012343:RNA, Transfer / Q000235:genetics / Q000378:metabolism*; D012270:Ribosomes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013816:Thermodynamics
D012333:RNA, Messenger; D012343:RNA, Transfer