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Search The CSA
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Catalytic Site Atlas

CSA LITERATURE entry for 1g8f

E.C. namesulfate adenylyltransferase
SpeciesSaccharomyces cerevisiae (Baker's yeast)
E.C. Number (IntEnz) 2.7.7.4
CSA Homologues of 1g8fThere are 17 Homologs
CSA Entries With UniProtID P08536
CSA Entries With EC Number 2.7.7.4
PDBe Entry 1g8f
PDBSum Entry 1g8f
MACiE Entry M0287

Literature Report

IntroductionATP sulphurylase from S.cerevisiae is able to catalyse the formation of adenosine-5-phosphosulphate. This functions as the first step in the incorporation of sulphate into biological molecules because it activates the sulphate towards nucleophilic attack by adding a good leaving group. The enzyme is part of a family of ATP sulphurylases which include those from the sulphur reducing bacteria, and proteins with dual kinase and sulphurylase activity found in mammals. The enzyme thus plays a vital role for cysteine and methionine biosynthetic pathways.
MechansimThe reaction proceeds via a single step nucleophilic substitution without a covalent enzyme bound intermediate being formed. The sulphate ion attacks the ATP molecule's alpha phosphate resulting in the PPi moiety acting as a leaving group and product (APS) formation. The pentavalent phosphate intermediate that forms as a result of the nucleophilic attack is stabilised by contact with Arg 290 and Magnesium, but the His-xx-His motif is involved purely in binding PPi rather than the general acid-base functionality observed in other members of the family, so are not considered catalytic for the purpose of this atlas, even though they are essential for the reaction to take place as without them the PPi product would not be stabilised.
Reaction

Catalytic Sites for 1g8f

Annotated By Reference To The Literature - Site 2 (Perform Site Search)
ResidueChainNumberUniProtKB NumberFunctional PartFunctionTargetDescription
ArgA290290macie:sideChainStabilises the pentavalent phosphate transition state.

Literature References

Notes:
Ullrich TC
Crystal structure of ATP sulfurylase from Saccharomyces cerevisiae, a key enzyme in sulfate activation.
EMBO J 2001 20 316-329
PubMed: 11157739
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