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2e1b

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Revision as of 15:04, 21 February 2008 by OCA (Talk | contribs)
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2e1b, resolution 2.70Å

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Crystal structure of the AlaX-M trans-editing enzyme from Pyrococcus horikoshii

Overview

The editing domain of alanyl-tRNA synthetase (AlaRS) contributes to high-fidelity aminoacylation by hydrolyzing (editing) the incorrect products Ser-tRNA(Ala) and Gly-tRNA(Ala) (cis-editing). The AlaX protein shares sequence homology to the editing domain of AlaRS. There are three types of AlaX proteins, with different numbers of amino-acid residues (AlaX-S, AlaX-M and AlaX-L). In this report, AlaX-M from Pyrococcus horikoshii is shown to deacylate Ser-tRNA(Ala) and Gly-tRNA(Ala) (trans-editing). The crystal structure of P. horikoshii AlaX-M has been determined at 2.7 A resolution. AlaX-M consists of an N-terminal domain (N-domain) and a C-terminal domain (C-domain). A zinc ion is coordinated by the conserved zinc-binding cluster in the C-domain, which is expected to be the enzymatic active site. The glycine-rich motif, consisting of successive conserved glycine residues in the N-domain, forms a loop (the 'glycine-rich loop'). The glycine-rich loop is located near the active site and may be involved in substrate recognition and/or catalysis.

About this Structure

2E1B is a Single protein structure of sequence from Pyrococcus horikoshii with as ligand. Full crystallographic information is available from OCA.

Reference

Structure of the AlaX-M trans-editing enzyme from Pyrococcus horikoshii., Fukunaga R, Yokoyama S, Acta Crystallogr D Biol Crystallogr. 2007 Mar;63(Pt 3):390-400. Epub 2007, Feb 21. PMID:17327676

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