Operating principles of rotary molecular motors: differences between F-1 and V-1 motors

Among the many types of bioenergy-transducing machineries, F-and V-ATPases are unique bio- and nano-molecular rotary motors. The rotational catalysis of F-1-ATPase has been investigated in detail, and molecular mechanisms have been proposed based on the crystal structures of the complex and on extensive single-molecule rotational observations. Recently, we obtained crystal structures of bacterial V-1-ATPase (A(3)B(3) and A(3)B(3)DF complexes) in the presence and absence of nucleotides. Based on these new structures, we present a novel model for the rotational catalysis mechanism of V-1-ATPase, which is different from that of F-1-ATPases.