ISSN 00062979, Biochemistry (Moscow), 2021, Vol. 86, No. 8, pp. 9921002. © Pleiades Publishing, Ltd., 2021. Published in Russian in Biokhimiya, 2021, Vol. 86, No. 8, pp. 11951206. REVIEW Ribosome as a Translocase and Helicase Chen Bao1,a and Dmitri N. Ermolenko1,b* 1Department of Biochemistry & Biophysics, School of Medicine and Dentistry and Center for RNA Biology, University of Rochester, Rochester, NY, USA aemail:
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[email protected] Received May 10, 2021 Revised May 21, 2021 Accepted May 21, 2021 Abstract—During protein synthesis, ribosome moves along mRNA to decode one codon after the other. Ribosome translo cation is induced by a universally conserved protein, elongation factor G (EFG) in bacteria and elongation factor 2 (EF2) in eukaryotes. EFGinduced translocation results in unwinding of the intramolecular secondary structures of mRNA by three base pairs at a time that renders the translating ribosome a processive helicase. Professor Alexander Sergeevich Spirin has made numerous seminal contributions to understanding the molecular mechanism of translocation. Here, we review Spirin’s insights into the ribosomal translocation and recent advances in the field that stemmed from Spirin’s pioneering work. We also discuss key remaining challenges in studies of translocase and helicase activities of the ribosome. DOI: 10.1134/S0006297921080095 Keywords: ribosome, translocation, helicase, power stroke, Brownian ratchet INTRODUCTION decades. Below we review key contributions of the Alexander Spirin’s laboratory and recent progress in During the elongation phase of protein synthesis, the investigations of ribosomal translocation that stemmed ribosome decodes sequences of codons by binding of the from the Spirin’s ideas.