1f4l

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spinqualitylabelsall models 1f4l, resolution 1.85Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

CRYSTAL STRUCTURE OF THE E.COLI METHIONYL-TRNA SYNTHETASE COMPLEXED WITH METHIONINE

Overview

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.

About this Structure

1F4L is a Single protein structure of sequence from Escherichia coli with and as ligands. Active as Methionine--tRNA ligase, with EC number 6.1.1.10 Full crystallographic information is available from OCA.

Reference

How methionyl-tRNA synthetase creates its amino acid recognition pocket upon L-methionine binding., Serre L, Verdon G, Choinowski T, Hervouet N, Risler JL, Zelwer C, J Mol Biol. 2001 Mar 2;306(4):863-76. PMID:11243794

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