1bs2
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(New page: 200px<br /><applet load="1bs2" size="450" color="white" frame="true" align="right" spinBox="true" caption="1bs2, resolution 2.75Å" /> '''YEAST ARGINYL-TRNA S...)
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Revision as of 09:45, 20 November 2007
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YEAST ARGINYL-TRNA SYNTHETASE
Overview
The crystal structure of arginyl-tRNA synthetase (ArgRS) from, Saccharomyces cerevisiae, a class I aminoacyl-tRNA synthetase (aaRS), with, L-arginine bound to the active site has been solved at 2.75 A resolution, and refined to a crystallographic R-factor of 19.7%. ArgRS is composed, predominantly of alpha-helices and can be divided into five domains, including the class I-specific active site. The N-terminal domain shows, striking similarity to some completely unrelated proteins and defines a, module which should participate in specific tRNA recognition. The, C-terminal domain, which is the putative anticodon-binding module, displays an all-alpha-helix fold highly similar to that of Escherichia, coli methionyl-tRNA synthetase. While ArgRS requires tRNAArg for the first, step of the aminoacylation reaction, the results show that its presence is, not a prerequisite for L-arginine binding. All H-bond-forming capability, of L-arginine is used by the protein for the specific recognition. The, guanidinium group forms two salt bridge interactions with two acidic, residues, and one H-bond with a tyrosine residue; these three residues are, strictly conserved in all ArgRS sequences. This tyrosine is also conserved, in other class I aaRS active sites but plays several functional roles. The, ArgRS structure allows the definition of a new framework for sequence, alignments and subclass definition in class I aaRSs.
About this Structure
1BS2 is a Single protein structure of sequence from Saccharomyces cerevisiae with ARG as ligand. Active as Arginine--tRNA ligase, with EC number 6.1.1.19 Full crystallographic information is available from OCA.
Reference
L-arginine recognition by yeast arginyl-tRNA synthetase., Cavarelli J, Delagoutte B, Eriani G, Gangloff J, Moras D, EMBO J. 1998 Sep 15;17(18):5438-48. PMID:9736621
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