Phosphoryl Transfer P-Type ATPases

Acylphosphate formation is characteristic for P-type ATPases and involves the transfer of the y-phosphate of ATP to an aspartic acid residue to form a high-energy enzyme intermediate. The phosphorylated aspartic acid residue is located in the sequence DKTGT, which is universally conserved in all members of the P-type superfamily. By this criterion, CopA and CopB of En. hirae are clearly members of the P-type superfamily of ATPases and probably function by the same underlying mechanism. Vanadate sensitivity is another hallmark of P-type ATPases. CopA and CopB were inhibited by vanadate with /50 values of around 0.1 mM. This is a low vanadate sensitivity compared to /50 values in the micromolar to submicromolar range observed for non-heavy metal P-type ATPases. 

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