1j20
From Proteopedia
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Crystal Structure of Thermus thermophilus HB8 Argininosuccinate Synthetase in complex with product
Overview
Argininosuccinate synthetase reversibly catalyzes the ATP-dependent, condensation of a citrulline with an aspartate to give argininosuccinate., The structures of the enzyme from Thermus thermophilus HB8 complexed with, intact ATP and substrates (citrulline and aspartate) and with AMP and, product (argininosuccinate) have been determined at 2.1- and 2.0-A, resolution, respectively. The enzyme does not show the ATP-induced domain, rotation observed in the enzyme from Escherichia coli. In the, enzyme-substrate complex, the reaction sites of ATP and the bound, substrates are adjacent and are sufficiently close for the reaction to, proceed without the large conformational change at the domain level. The, mobility of the triphosphate group in ATP and the side chain of citrulline, play an important role in the catalytic action. The protonated amino group, of the bound aspartate interacts with the alpha-phosphate of ATP and the, ureido group of citrulline, thus stimulating the adenylation of, citrulline. The enzyme-product complex explains how the citrullyl-AMP, intermediate is bound to the active site. The stereochemistry of the, catalysis of the enzyme is clarified on the basis of the structures of, tAsS (argininosuccinate synthetase from T. thermophilus HB8) complexes.
About this Structure
1J20 is a Single protein structure of sequence from Thermus thermophilus with SO4, AMP and AS1 as ligands. Active as Argininosuccinate synthase, with EC number 6.3.4.5 Full crystallographic information is available from OCA.
Reference
Structures of argininosuccinate synthetase in enzyme-ATP substrates and enzyme-AMP product forms: stereochemistry of the catalytic reaction., Goto M, Omi R, Miyahara I, Sugahara M, Hirotsu K, J Biol Chem. 2003 Jun 20;278(25):22964-71. Epub 2003 Apr 8. PMID:12684518
Page seeded by OCA on Tue Nov 20 17:52:23 2007
