title: Kinetics of Spontaneous and EF-G-Accelerated Rotation of Ribosomal Subunits.
abstract: Ribosome dynamics play an important role in translation. The rotation of the ribosomal subunits relative to one another is essential for tRNA-mRNA translocation. An important unresolved question is whether subunit rotation limits the rate of translocation. Here, we monitor subunit rotation relative to peptide bond formation and translocation using ensemble kinetics and single-molecule FRET. We observe that spontaneous forward subunit rotation occurs at a rate of 40 s(-1), independent of the rate of preceding peptide bond formation. Elongation factor G (EF-G) accelerates forward subunit rotation to 200 s(-1). tRNA-mRNA movement is much slower (10-40 s(-1)), suggesting that forward subunit rotation does not limit the rate of translocation. The transition back to the non-rotated state of the ribosome kinetically coincides with tRNA-mRNA movement. Thus, large-scale movements of the ribosome are intrinsically rapid and gated by its ligands such as EF-G and tRNA.
authors.affiliation: Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.
authors.forename: Heena
authors.initials: H
authors.lastname: Sharma
authors.affiliation: Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.
authors.forename: Sarah
authors.initials: S
authors.lastname: Adio
authors.affiliation: Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.
authors.forename: Tamara
authors.initials: T
authors.lastname: Senyushkina
authors.affiliation: Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Belardinelli
authors.affiliation: Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Peske
authors.affiliation: Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany. Electronic address: rodnina@mpibpc.mpg.de.
authors.forename: Marina V
authors.initials: MV
authors.lastname: Rodnina
mesh_terms: D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer; D006160:Guanosine Triphosphate / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D020653:Peptide Elongation Factor G / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D012343:RNA, Transfer / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D054657:Ribosome Subunits / Q000235:genetics* / Q000378:metabolism; D012399:Rotation
chemical_list: D020653:Peptide Elongation Factor G; D012333:RNA, Messenger; D006160:Guanosine Triphosphate; D012343:RNA, Transfer