The E1/E2-Preference of Gastric H,K-ATPase Mutants
Gastric H,K-ATPase has, in the absence of ATP and added ions, a preference for the E2 conformation. Mutations in the cation-binding pocket often result in a preference for the E1-conformation. This can be paralleled by the occurrence of K+-independent ATPase activity. These two phenomena could be separated by combined mutagenesis of several residues in and around the cation-binding pocket. Models of the three-dimensional structure of H,K-ATPase visualize the relationship between the E1/E2 preference and the structure.
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