Fo·F1 ATP synthases/ATPases (Fo·F1) catalyze ATP synthesis by consuming energy of electrochemical potential of hydrogen ions (pmf), or ATP hydrolysis resulting in the pmf formation. It is generally accepted to consider Fo·F1 as a reversible chemomechanical-electrical molecular machine, however: (i) the mechanism of energy-dependent ATP synthesis is based only on the data on hydrolytic activity of the enzyme, (ii) Fo·F1 from a number of organisms effectively synthesize, but is unable to hydrolyze ATP, which indicates non-observance of the principle of microreversibility and requires development of a new hypotheses concerning the enzyme mechanism. Since 1980, the group of A. D. Vinogradov has been developing a concept according to which the elementary catalysis stages of ATP hydrolysis and ATP synthesis do not coincide, and there are two independently operating forms of Fo·F1 in the coupled membranes - pmf-generating ATPase and pmf-consuming ATP synthase. Fo·F1 of P. denitrificans as a natural model of an irreversibly functioning enzyme is a convenient object for experimental verification of the hypothesis of unidirectional energy conversion. The review considers modern concepts of the molecular mechanisms of regulation of Fo·F1 ATP synthase/ATPase of P. denitrificans and development of the hypothesis of two forms of Fo·F1.
Keywords:
Fo·F1 ATP synthase/ATPase;