1jec
From Proteopedia
Crystal Structure of ATP Sulfurylase in complex with thiosulfate
Structural highlights
FunctionMET3_YEAST Catalyzes the first intracellular reaction of sulfate assimilation, forming adenosine-5'-phosphosulfate (APS) from inorganic sulfate and ATP. Plays an important role in sulfate activation as a component of the biosynthesis pathway of sulfur-containing amino acids.[HAMAP-Rule:MF_03106] 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 PubMedThe ubiquitous enzyme ATP sulfurylase (ATPS) catalyzes the primary step of intracellular sulfate activation, the formation of adenosine 5'-phosphosulfate (APS). It has been shown that the enzyme catalyzes the generation of APS from ATP and inorganic sulfate in vitro and in vivo, and that this reaction can be inhibited by a number of simple molecules. Here, we present the crystal structures of ATPS from the yeast Saccharomyces cerevisiae complexed with compounds that have inhibitory effects on the catalytic reaction of ATPS. Thiosulfate and ADP mimic the substrates sulfate and ATP in the active site, but are non-reactive and thus competitive inhibitors of the sulfurylase reaction. Chlorate is bound in a crevice between the active site and the intermediate domain III of the complex structure. It forms hydrogen bonds to residues of both domains and stabilizes a "closed" conformation, inhibiting the release of the reaction products APS and PPi. These new observations are evidence for the crucial role of the displacement mechanism for the catalysis by ATPS. The complex structures of ATP sulfurylase with thiosulfate, ADP and chlorate reveal new insights in inhibitory effects and the catalytic cycle.,Ullrich TC, Huber R J Mol Biol. 2001 Nov 9;313(5):1117-25. PMID:11700067[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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