Abstract
E. coli threonyl-tRNA synthetase (ThrRS) is a class II enzyme that represses the translation of its own mRNA. We report the crystal structure at 2.9 A resolution of the complex between tRNA(Thr) and ThrRS, whose structural features reveal novel strategies for providing specificity in tRNA selection. These include an amino-terminal domain containing a novel protein fold that makes minor groove contacts with the tRNA acceptor stem. The enzyme induces a large deformation of the anticodon loop, resulting in an interaction between two adjacent anticodon bases, which accounts for their prominent role in tRNA identity and translational regulation. A zinc ion found in the active site is implicated in amino acid recognition/discrimination.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acyl-tRNA Synthetases / chemistry*
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Amino Acyl-tRNA Synthetases / genetics
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Amino Acyl-tRNA Synthetases / metabolism*
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Bacterial Proteins / chemistry
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Bacterial Proteins / genetics
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Bacterial Proteins / metabolism
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Base Sequence
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Binding Sites / genetics
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Catalytic Domain
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Dimerization
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Enzyme Activation / physiology
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Escherichia coli / enzymology
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Escherichia coli / genetics
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Genetic Complementation Test
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Molecular Mimicry
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Molecular Sequence Data
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Nucleic Acid Conformation
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Protein Structure, Secondary
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Protein Structure, Tertiary
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RNA, Messenger / genetics
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RNA, Transfer, Amino Acyl / chemistry*
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RNA, Transfer, Amino Acyl / genetics
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RNA, Transfer, Amino Acyl / metabolism*
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Sequence Homology, Amino Acid
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Zinc / chemistry*
Substances
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Bacterial Proteins
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RNA, Messenger
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RNA, Transfer, Amino Acyl
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Amino Acyl-tRNA Synthetases
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Zinc