Abstract
At termination of protein synthesis, type I release factors promote hydrolysis of the peptidyl-transfer RNA linkage in response to recognition of a stop codon. Here we describe the crystal structure of the Thermus thermophilus 70S ribosome in complex with the release factor RF1, tRNA and a messenger RNA containing a UAA stop codon, at 3.2 A resolution. The stop codon is recognized in a pocket formed by conserved elements of RF1, including its PxT recognition motif, and 16S ribosomal RNA. The codon and the 30S subunit A site undergo an induced fit that results in stabilization of a conformation of RF1 that promotes its interaction with the peptidyl transferase centre. Unexpectedly, the main-chain amide group of Gln 230 in the universally conserved GGQ motif of the factor is positioned to contribute directly to peptidyl-tRNA hydrolysis.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Codon, Terminator / genetics
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Codon, Terminator / metabolism
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Crystallography, X-Ray
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Models, Molecular
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Peptide Chain Termination, Translational*
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Peptide Termination Factors / chemistry
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Peptide Termination Factors / metabolism
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Peptidyl Transferases / chemistry
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Peptidyl Transferases / metabolism
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Protein Binding
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Protein Structure, Tertiary
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RNA, Bacterial / metabolism
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RNA, Ribosomal, 23S / chemistry
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RNA, Transfer / chemistry
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RNA, Transfer / genetics
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RNA, Transfer / metabolism
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Ribosomes / chemistry*
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Ribosomes / metabolism*
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Thermus thermophilus / chemistry*
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Thermus thermophilus / metabolism
Substances
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Codon, Terminator
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Peptide Termination Factors
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RNA, Bacterial
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RNA, Ribosomal, 23S
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RNA, Transfer
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Peptidyl Transferases
Associated data
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PDB/3D5A
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PDB/3D5B
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PDB/3D5C
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PDB/3D5D