The E-1/E-2-Preference Of Gastric H,K-Atpase Mutants

Gastric H,K-ATPase has, in the absence of ATP and added ions, a preference for the E-2 conformation. Mutations in the cation-binding pocket often result in a preference for the E-1-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 E-1/E-2 preference and the structure.