Progression of the ribosome recycling factor through the ribosome dissociates the two ribosomal subunits.
After the termination step of translation, the posttermination complex (PoTC), composed of the ribosome, mRNA, and a deacylated tRNA, is processed by the concerted action of the ribosome-recycling factor (RRF), elongation factor G (EF-G), and GTP to prepare the ribosome for a fresh round of protein synthesis. However, the sequential steps of dissociation of the ribosomal subunits, and release of mRNA and deacylated tRNA from the PoTC, are unclear. Using three-dimensional cryo-electron microscopy, in conjunction with undecagold-labeled RRF, we show that RRF is capable of spontaneously moving from its initial binding site on the 70S Escherichia coli ribosome to a site exclusively on the large 50S ribosomal subunit. This movement leads to disruption of crucial intersubunit bridges and thereby to the dissociation of the two ribosomal subunits, the central event in ribosome recycling. Results of this study allow us to propose a model of ribosome recycling.
Barat
Chandana
C
Division of Molecular Medicine, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY 12201-0509, USA.
Datta
Partha P
PP
Division of Molecular Medicine, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY 12201-0509, USA.
Raj
V Samuel
VS
Department of Microbiology, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Sharma
Manjuli R
MR
Division of Molecular Medicine, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY 12201-0509, USA.
Kaji
Hideko
H
Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
Kaji
Akira
A
Department of Microbiology, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Agrawal
Rajendra K
RK
Division of Molecular Medicine, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY 12201-0509, USA; Department of Biomedical Sciences, School of Public Health, State University of New York at Albany, Albany, NY 12201, USA. Electronic address: agrawal@wadsworth.org.
D001665:Binding Sites; D020285:Cryoelectron Microscopy; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism; D046911:Macromolecular Substances; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000378:metabolism; D008954:Models, Biological; D008958:Models, Molecular; D020653:Peptide Elongation Factor G / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D012329:RNA, Bacterial / Q000737:chemistry / Q000378:metabolism; D012343:RNA, Transfer / Q000737:chemistry / Q000378:metabolism; D012269:Ribosomal Proteins / Q000737:chemistry / Q000378:metabolism*; D012270:Ribosomes / Q000737:chemistry / Q000378:metabolism*
D029968:Escherichia coli Proteins; D046911:Macromolecular Substances; D026901:Membrane Transport Proteins; D020653:Peptide Elongation Factor G; C096376:PotC protein, E coli; D012329:RNA, Bacterial; D012269:Ribosomal Proteins; C087267:ribosome releasing factor; D012343:RNA, Transfer