Get   for     ? 
 Site search     ? 
Catalytic Site Atlas Version 2.2.12
Find Annotated Site: PDB code:
Swiss-Prot code:
EC number:
Help
CSA entry for 1f48
Original Entry
Title:
Hydrolase
Compound:
Arsenite-translocating atpase
Mutant:
No
UniProt/Swiss-Prot:
P08690-ARA1_ECOLI
EC Class:
3.6.3.16
Other CSA Entries:
Overview of all sites for 1f48
Homologues of 1f48
Entries for UniProt/Swiss-Prot: P08690
Entries for EC: 3.6.3.16
Other Databases:
PDB entry: 1f48
PDBsum entry: 1f48
UniProt/Swiss-Prot: P08690
IntEnz entry: 3.6.3.16
Literature Report:
Introduction:
The 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.
Mechanism:
The 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.
Sites:

Click to Display Catalytic Site (Get help with this section)
Found by:
Literature reference 

ResidueChainNumberUniProt numberFunctional part FunctionTargetDescription
GLYA 18 18Backbone amide
ElectrostaticTransition state
Amide forms electrostatic contacts with the gamma phosphate of ATP, thus stabilises the pentavalent phosphate transition state.
Evidence from paper Evidence concerns Evidence type
PubMed ID 10970874 Current protein Structural similarity to homologue of known mechanism
PubMed ID 10970874 Current protein Residue is positioned appropriately (ligand position known)

ResidueChainNumberUniProt numberFunctional part FunctionTargetDescription
LYSA 21 21Sidechain
ElectrostaticTransition state
Forms contacts with the gamma phosphate of ATP, thus stabilises the pentavalent phosphate intermediate.
Evidence from paper Evidence concerns Evidence type
PubMed ID 10970874 Current protein Residue is positioned appropriately (ligand position known)
PubMed ID 10970874 Current protein Structural similarity to homologue of known mechanism

ResidueChainNumberUniProt numberFunctional part FunctionTargetDescription
MGA 592 0
ElectrostaticTransition state
Stabilises pentavalent phosphate transition state by contacts with the gamma phosphate of ATP.
Evidence from paper Evidence concerns Evidence type
PubMed ID 10970874 Current protein Structural similarity to homologue of known mechanism
PubMed ID 10970874 Current protein Residue is positioned appropriately (ligand position known)
References:
1
Structure of the ArsA ATPase: the catalytic subunit of a heavy metal resistance pump.
T. Zhou and S. Radaev and B. P. Rosen and D. L. Gatti
EMBO J 19, (17) 4838-45, (2000).
10970874
Which EBI biological databases are available and how do I access them? EBI Site Map