1nht

ENTRAPMENT OF 6-THIOPHOSPHORYL-IMP IN THE ACTIVE SITE OF CRYSTALLINE ADENYLOSUCCINATE SYNTHETASE FROM ESCHERICHIA COLI DATA COLLECTED AT 100K

spinqualitylabelsall models 1nht, resolution 2.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1nht is a 1 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GDP, HDA, MG, PGS Activity: Adenylosuccinate synthase, with EC number 6.3.4.4 Resources: FirstGlance, OCA, RCSB, PDBsum Function [PURA_ECOLI] Plays an important role in the de novo pathway of purine nucleotide biosynthesis. Catalyzes the first committed step in the biosynthesis of AMP from IMP (By similarity).[HAMAP-Rule:MF_00011] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Crystal structures of adenylosuccinate synthetase from Escherichia coli complexed with Mg2+, 6-thiophosphoryl-IMP, GDP, and hadacidin at 298 and 100 K have been refined to R-factors of 0.171 and 0.206 against data to 2.8 and 2.5 A resolution, respectively. Interactions of GDP, Mg2+ and hadacidin are similar to those observed for the same ligands in the complex of IMP, GDP, NO3-, Mg2+ and hadacidin (Poland, B. W., Fromm, H. J. & Honzatko, R. B. (1996). J. Mol. Biol. 264, 1013-1027). Although crystals were grown from solutions containing 6-mercapto-IMP and GTP, the electron density at the active site is consistent with 6-thiophosphoryl-IMP and GDP. Asp-13 and Gln-224 probably work in concert to stabilize the 6-thioanion of 6-mercapto-IMP, which in turn is the nucleophile in the displacement of GDP from the gamma-phosphate of GTP. Once formed, 6-thiophosphoryl-IMP is stable in the active site of the enzyme under the conditions of the structural investigation. The direct observation of 6-thiophosphoryl-IMP in the active site is consistent with the putative generation of 6-phosphoryl-IMP along the reaction pathway of the synthetase. Entrapment of 6-thiophosphoryl-IMP in the active site of crystalline adenylosuccinate synthetase from Escherichia coli.,Poland BW, Bruns C, Fromm HJ, Honzatko RB J Biol Chem. 1997 Jun 13;272(24):15200-5. PMID:9182542 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Adenylosuccinate Synthetase

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