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PDBsum entry 1f4l
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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How methionyl-Trna synthetase creates its amino acid recognition pocket upon l-Methionine binding.
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Authors
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L.Serre,
G.Verdon,
T.Choinowski,
N.Hervouet,
J.L.Risler,
C.Zelwer.
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Ref.
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J Mol Biol, 2001,
306,
863-876.
[DOI no: ]
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PubMed id
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Abstract
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Amino acid selection by aminoacyl-tRNA synthetases requires efficient mechanisms
to avoid incorrect charging of the cognate tRNAs. A proofreading mechanism
prevents Escherichia coli methionyl-tRNA synthetase (EcMet-RS) from activating
in vivo L-homocysteine, a natural competitor of L-methionine recognised by the
enzyme. The crystal structure of the complex between EcMet-RS and L-methionine
solved at 1.8 A resolution exhibits some conspicuous differences with the
recently published free enzyme structure. Thus, the methionine delta-sulphur
atom replaces a water molecule H-bonded to Leu13N and Tyr260O(eta) in the free
enzyme. Rearrangements of aromatic residues enable the protein to form a
hydrophobic pocket around the ligand side-chain. The subsequent formation of an
extended water molecule network contributes to relative displacements, up to 3
A, of several domains of the protein. The structure of this complex supports a
plausible mechanism for the selection of L-methionine versus L-homocysteine and
suggests the possibility of information transfer between the different
functional domains of the enzyme.
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Figure 6.
Figure 6. Conformational changes in the area of helix aE
and strand b5 with ball-and-stick representation for the
complexed and free protein. The native protein is shown green
and the complex is red.
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Figure 8.
Figure 8. Superimposition of the a-carbon backbones of the
anticodon recognition domain for the free and the complexed
Met-RS. The colour code is the same as that used in Figure 7.
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The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(2001,
306,
863-876)
copyright 2001.
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