1g51
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ASPARTYL TRNA SYNTHETASE FROM THERMUS THERMOPHILUS AT 2.4 A RESOLUTION
OverviewOverview
The crystal structures of Thermus thermophilus aspartyl-tRNA synthetase, and of its complex with ATP, Mg2+ and aspartic acid, show in situ, formation of the amino acid adenylate and furnish experimental evidence, for the modes of recognition of aspartic acid and ATP. The amino acid fits, in a predefined specific site in which it replaces water molecules without, significant conformational changes of the binding residues. This mode of, selection is reminiscent of the lock and key concept. The pocket is closed, by the movement of a histidine side chain from a neighbouring loop acting, as a valve. ATP binding is driven by the stacking of the adenine upon the, otherwise fixed aromatic ring of the class-II-invariant phenylalanine, Phe235. Specific recognition is achieved by interactions with the flexible, side chains of other class-II-conserved residues. Conformational changes, have been identified which allow the description of a reaction pathway, including both lock-and-key and induced-fit interactions. This pathway can, presumably be extended to all class II aaRS.
About this StructureAbout this Structure
1G51 is a Single protein structure of sequence from Thermus thermophilus with SO4, AMO and AMP as ligands. Active as Aspartate--tRNA ligase, with EC number 6.1.1.12 Full crystallographic information is available from OCA.
ReferenceReference
Synthesis and recognition of aspartyl-adenylate by Thermus thermophilus aspartyl-tRNA synthetase., Poterszman A, Delarue M, Thierry JC, Moras D, J Mol Biol. 1994 Nov 25;244(2):158-67. PMID:7966328
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