1asy
CLASS II AMINOACYL TRANSFER RNA SYNTHETASES: CRYSTAL STRUCTURE OF YEAST ASPARTYL-TRNA SYNTHETASE COMPLEXED WITH TRNA ASP
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OverviewOverview
The crystal structure of the binary complex tRNA(Asp)-aspartyl tRNA, synthetase from yeast was solved with the use of multiple isomorphous, replacement to 3 angstrom resolution. The dimeric synthetase, a member of, class II aminoacyl tRNA synthetases (aaRS's) exhibits the characteristic, signature motifs conserved in eight aaRS's. These three sequence motifs, are contained in the catalytic site domain, built around an antiparallel, beta sheet, and flanked by three alpha helices that form the pocket in, which adenosine triphosphate (ATP) and the CCA end of tRNA bind. The, tRNA(Asp) molecule approaches the synthetase from the variable loop side., The two major contact areas are with the acceptor end and the anticodon, stem and loop. In both sites the protein interacts with the tRNA from the, major groove side. The correlation between aaRS class II and the initial, site of aminoacylation at 3'-OH can be explained by the structure. The, molecular association leads to the following features: (i) the backbone of, the GCCA single-stranded portion of the acceptor end exhibits a regular, helical conformation; (ii) the loop between residues 320 and 342 in motif, 2 interacts with the acceptor stem in the major groove and is in contact, with the discriminator base G and the first base pair UA; and (iii) the, anticodon loop undergoes a large conformational change in order to bind, the protein. The conformation of the tRNA molecule in the complex is, dictated more by the interaction with the protein than by its own, sequence.
About this StructureAbout this Structure
1ASY is a Single protein structure of sequence from Saccharomyces cerevisiae. Active as Aspartate--tRNA ligase, with EC number 6.1.1.12 Full crystallographic information is available from OCA.
ReferenceReference
Class II aminoacyl transfer RNA synthetases: crystal structure of yeast aspartyl-tRNA synthetase complexed with tRNA(Asp)., Ruff M, Krishnaswamy S, Boeglin M, Poterszman A, Mitschler A, Podjarny A, Rees B, Thierry JC, Moras D, Science. 1991 Jun 21;252(5013):1682-9. PMID:2047877
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