INFERENCES ABOUT THE CATALYTIC DOMAIN OF P-TYPE ATPASES FROM THE TERTIARY STRUCTURES OF ENZYMES THAT CATALYZE THE SAME ELEMENTARY REACTION

The machinery to catalyze elementary reactions is conserved, and the n umber of solved enzyme structures is increasing exponentially, Therefo re, structures of enzymes that catalyze phosphate transfer are reviewe d, and a supersecondary structure connecting the Walker A sequence to another sequence containing functional amino acids is proposed as an a dditional signature for the active site, The new signature is used to infer the identity of the P-loop in P-type biological pumps and may be useful in predicting targets for site-directed mutagenesis in other e nzymes of unknown structure like the AAA family and ABC transporters, (C) 1998 Federation of European Biochemical Societies.