Abstract
During the ribosomal translocation, the binding of elongation factor G (EF-G) to the pretranslocational ribosome leads to a ratchet-like rotation of the 30S subunit relative to the 50S subunit in the direction of the mRNA movement. By means of cryo-electron microscopy we observe that this rotation is accompanied by a 20 A movement of the L1 stalk of the 50S subunit, implying that this region is involved in the translocation of deacylated tRNAs from the P to the E site. These ribosomal motions can occur only when the P-site tRNA is deacylated. Prior to peptidyl-transfer to the A-site tRNA or peptide removal, the presence of the charged P-site tRNA locks the ribosome and prohibits both of these motions.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Binding Sites / genetics
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Cryoelectron Microscopy
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Eukaryotic Cells / metabolism*
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Eukaryotic Cells / ultrastructure
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Models, Molecular
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Molecular Conformation
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Peptide Elongation Factor G / genetics
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Peptide Elongation Factor G / metabolism*
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Peptides / genetics
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Peptides / metabolism
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Protein Biosynthesis / genetics*
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Protein Structure, Tertiary / genetics
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Protein Subunits / genetics
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Protein Subunits / metabolism
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RNA, Messenger / genetics
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RNA, Messenger / metabolism*
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RNA, Messenger / ultrastructure
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RNA, Transfer / genetics
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RNA, Transfer / metabolism*
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RNA, Transfer / ultrastructure
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Ribosomes / genetics
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Ribosomes / metabolism*
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Ribosomes / ultrastructure
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Rotation
Substances
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Peptide Elongation Factor G
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Peptides
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Protein Subunits
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RNA, Messenger
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RNA, Transfer
Associated data
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PDB/1PN6
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PDB/1PN7
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PDB/1PN8