1pg0
|
Methionyl-trna synthetase from escherichia coli complexed with methioninyl adenylate
OverviewOverview
Binding of methionine to methionyl-tRNA synthetase (MetRS) is known to, promote conformational changes within the active site. However, the, contribution of these rearrangements to enzyme catalysis is not fully, understood. In this study, several methionine and methionyl adenylate, analogues were diffused into crystals of the monomeric form of Escherichia, coli methionyl-tRNA synthetase. The structures of the corresponding, complexes were solved at resolutions below 1.9A and compared to those of, the enzyme free or complexed with methionine. Residues Y15 and W253 play, key roles in the strength of the binding of the amino acid and of its, analogues. Indeed, full motions of these residues are required to recover, the maximum in free energy of binding. Residue Y15 also controls the size, of the hydrophobic pocket where the amino acid side-chain interacts. H301, appears to participate to the specific recognition of the sulphur atom of, methionine. Complexes with methionyl adenylate analogues illustrate the, shielding by MetRS of the region joining the methionine and adenosine, moieties. Finally, the structure of MetRS complexed to a methionine, analogue mimicking the tetrahedral carbon of the transition state in the, aminoacylation reaction was solved. On the basis of this model, we propose, that, in response to the binding of the 3'-end of tRNA, Y15 moves again in, order to deshield the anhydride bond in the natural adenylate.
About this StructureAbout this Structure
1PG0 is a Single protein structure of sequence from Escherichia coli with MOD as ligand. Active as Methionine--tRNA ligase, with EC number 6.1.1.10 Full crystallographic information is available from OCA.
ReferenceReference
Use of analogues of methionine and methionyl adenylate to sample conformational changes during catalysis in Escherichia coli methionyl-tRNA synthetase., Crepin T, Schmitt E, Mechulam Y, Sampson PB, Vaughan MD, Honek JF, Blanquet S, J Mol Biol. 2003 Sep 5;332(1):59-72. PMID:12946347
Page seeded by OCA on Tue Nov 20 23:46:28 2007