Structure-function relationships of A-, F- and V-ATPases

Ion-translocating ATPases, such as the F1Fo-, V1Vo- and archaeal A(1)A(o) e nzymes, are essential cellular energy converters which transduce the chemic al energy of ATP hydrolysis into transmembrane ionic electrochemical potent ial differences. Based on subunit composition and primary structures of the subunits, these types of ATPases are related through evolution; however, t hey differ with respect to function. Recent work has focused on the three-d imensional structural relationships of the major, nucleotide-binding subuni ts A and B of the A(1)/V-1-ATPases and the corresponding beta and alpha sub units of the F-1-ATPase, and the location of the coupling subunits within t he stalk that provide the physical linkage between the regions of ATP hydro lysis and ion transduction. This review focuses on the structural homologie s and diversities of A(1)-, F-1- and V-1-ATPases, in particular on signific ant differences between the stalk regions of these families of enzymes.