1gax

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Revision as of 06:53, 18 November 2007

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spinqualitylabelsall models 1gax, resolution 2.9Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

CRYSTAL STRUCTURE OF THERMUS THERMOPHILUS VALYL-TRNA SYNTHETASE COMPLEXED WITH TRNA(VAL) AND VALYL-ADENYLATE ANALOGUE

Overview

Valyl-tRNA synthetase (ValRS) strictly discriminates the cognate L-valine, from the larger L-isoleucine and the isosteric L-threonine by the, tRNA-dependent "double sieve" mechanism. In this study, we determined the, 2.9 A crystal structure of a complex of Thermus thermophilus ValRS, tRNA(Val), and an analog of the Val-adenylate intermediate. The analog is, bound in a pocket, where Pro(41) allows accommodation of the Val and Thr, moieties but precludes the Ile moiety (the first sieve), on the, aminoacylation domain. The editing domain, which hydrolyzes incorrectly, synthesized Thr-tRNA(Val), is bound to the 3' adenosine of tRNA(Val). A, contiguous pocket was found to accommodate the Thr moiety, but not the Val, moiety (the second sieve). Furthermore, another Thr binding pocket for, Thr-adenylate hydrolysis was suggested on the editing domain.

About this Structure

1GAX is a Single protein structure of sequence from Thermus thermophilus with ZN and VAA as ligands. The following page contains interesting information on the relation of 1GAX with [Aminoacyl-tRNA Synthetases]. Active as Valine--tRNA ligase, with EC number 6.1.1.9 Full crystallographic information is available from OCA.

Reference

Structural basis for double-sieve discrimination of L-valine from L-isoleucine and L-threonine by the complex of tRNA(Val) and valyl-tRNA synthetase., Fukai S, Nureki O, Sekine S, Shimada A, Tao J, Vassylyev DG, Yokoyama S, Cell. 2000 Nov 22;103(5):793-803. PMID:11114335

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