1nyr
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Structure of Staphylococcus aureus threonyl-tRNA synthetase complexed with ATP
OverviewOverview
The crystal structures of threonyl-tRNA synthetase (ThrRS) from, Staphylococcus aureus, with ATP and an analogue of threonyl adenylate, are, described. Together with the previously determined structures of, Escherichia coli ThrRS with different substrates, they allow a, comprehensive analysis of the effect of binding of all the substrates:, threonine, ATP and tRNA. The tRNA, by inserting its acceptor arm between, the N-terminal domain and the catalytic domain, causes a large rotation of, the former. Within the catalytic domain, four regions surrounding the, active site display significant conformational changes upon binding of the, different substrates. The binding of threonine induces the movement of as, much as 50 consecutive amino acid residues. The binding of ATP triggers a, displacement, as large as 8A at some C(alpha) positions, of a, strand-loop-strand region of the core beta-sheet. Two other regions move, in a cooperative way upon binding of threonine or ATP: the motif 2 loop, which plays an essential role in the first step of the aminoacylation, reaction, and the ordering loop, which closes on the active site cavity, when the substrates are in place. The tRNA interacts with all four mobile, regions, several residues initially bound to threonine or ATP switching to, a position in which they can contact the tRNA. Three such conformational, switches could be identified, each of them in a different mobile region., The structural analysis suggests that, while the small substrates can bind, in any order, they must be in place before productive tRNA binding can, occur.
About this StructureAbout this Structure
1NYR is a Single protein structure of sequence from Staphylococcus aureus with ZN, ATP and THR as ligands. Active as Threonine--tRNA ligase, with EC number 6.1.1.3 Full crystallographic information is available from OCA.
ReferenceReference
Conformational movements and cooperativity upon amino acid, ATP and tRNA binding in threonyl-tRNA synthetase., Torres-Larios A, Sankaranarayanan R, Rees B, Dock-Bregeon AC, Moras D, J Mol Biol. 2003 Aug 1;331(1):201-11. PMID:12875846
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