1a8h

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Revision as of 08:33, 20 November 2007

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spinqualitylabelsall models 1a8h, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

METHIONYL-TRNA SYNTHETASE FROM THERMUS THERMOPHILUS

Overview

Background: The 20 aminoacyl-tRNA synthetases are divided into two, classes, I and II. The 10 class I synthetases are considered to have in, common the catalytic domain structure based on the Rossmann fold, which is, totally different from the class II catalytic domain structure. The class, I synthetases are further divided into three subclasses, a, b and c, according to sequence homology. No conserved structural features for tRNA, recognition by class I synthetases have been established. Results: We, determined the crystal structure of the class Ia methionyl-tRNA synthetase, (MetRS) at 2.0 A resolution, using MetRS from an extreme thermophile, Thermus thermophilus HB8. The T. thermophilus MetRS structure is in full, agreement with the biochemical and genetic data from Escherichia coli, MetRS. The conserved 'anticodon-binding' residues are spatially clustered, on an alpha-helix-bundle domain. The Rossmann-fold and anticodon-binding, domains are connected by a beta-alpha-alpha-beta-alpha topology ('SC, fold') domain that contains the class I specific KMSKS motif. Conclusions:, The alpha-helix-bundle domain identified in the MetRS structure is the, signature of the class Ia enzymes, as it was also identified in the class, Ia structures of the isoleucyl- and arginyl-tRNA synthetases. The, beta-alpha-alpha-beta-alpha topology domain, which can now be identified, in all known structures of the class Ia and Ib synthetases, is likely to, dock with the inner side of the L-shaped tRNA, thereby positioning the, anticodon stem.

About this Structure

1A8H is a Single protein structure of sequence from Thermus thermophilus with ZN as ligand. Active as Methionine--tRNA ligase, with EC number 6.1.1.10 Full crystallographic information is available from OCA.

Reference

The 2.0 A crystal structure of Thermus thermophilus methionyl-tRNA synthetase reveals two RNA-binding modules., Sugiura I, Nureki O, Ugaji-Yoshikawa Y, Kuwabara S, Shimada A, Tateno M, Lorber B, Giege R, Moras D, Yokoyama S, Konno M, Structure. 2000 Feb 15;8(2):197-208. PMID:10673435

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