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Search The CSA
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Catalytic Site Atlas

CSA LITERATURE entry for 1f48

E.C. namearsenite-transporting ATPase
SpeciesEscherichia coli (Bacteria)
E.C. Number (IntEnz) 3.6.3.16
CSA Homologues of 1f48There are 28 Homologs
CSA Entries With UniProtID P08690
CSA Entries With EC Number 3.6.3.16
PDBe Entry 1f48
PDBSum Entry 1f48
MACiE Entry 1f48

Literature Report

IntroductionThe ArsAB pump is able to catalyse the active transport of toxic heavy metal ions out of the cell. Since heavy metal ions such as arsenic are able to bind irreversibly to many enzymes and permanently deactivate them, it is essential for the survival of the organism that such pumps work correctly; inhibition of these pumps in bacteria may therefore be an antibiotic target. The enzyme uses changes in the tertiary structure that occur when ATP is hydrolysed in order to power the transport of the heavy metal ions against the concentration gradient across the cell membrane, and is activated by the binding of metalloids such as antimony (Sb III) to allosteric sites. The transporter is part of a wider family of ATP utilising proteins, all of which display the Rossman fold, including such well known examples as the ABC transporters.
MechansimThe catalytic activity of the ATP hydrolysing subunit of the protein is provided by the residues Lys 21 and Gly 18, along with Mg2+, all of which act together to stabilise the pentavalent phosphate transition state that forms when a water molecule acts as a nucleophile to attack the gamma phosphate of ATP. The phosphate leaving group acts as the base to deprotonate the water molecule.
Reaction

Catalytic Sites for 1f48

Annotated By Reference To The Literature - Site 1 (Perform Site Search)
ResidueChainNumberUniProtKB NumberFunctional PartFunctionTargetDescription
LysA2121macie:sideChainForms contacts with the gamma phosphate of ATP, thus stabilises the pentavalent phosphate intermediate.
GlyA1818macie:mainChainAmideAmide forms electrostatic contacts with the gamma phosphate of ATP, thus stabilises the pentavalent phosphate transition state.

Literature References

Notes:
Zhou T
Structure of the ArsA ATPase: the catalytic subunit of a heavy metal resistance pump.
EMBO J 2000 19 4838-4845
PubMed: 10970874
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