Electrostatic interactions in catalytic centers of F1-ATPase

The first part of this paper is a brief review of works concerned with the mechanisms of functioning of F0F1-ATP synthases. F0F1-ATP syntheses operate as rotating molecular machines that provide the synthesis of ATP from ADP and inorganic phosphate (Pi) in mitochondria, chloroplasts, and bacteria at the expense of the energy of electrochemical gradient of hydrogen ions generated across energy-transducing mitochondrial, chloroplast or, bacterial membranes. A distinguishing feature of these enzymes is that they operate as rotary molecular motors. In the second part of the work, we calculated the contribution of electrostatic interactions between charged groups of a substrate (MgATP), reaction products (MgADP and Pi), and charged amino acid residues of the F1-ATPase molecule to energy changes associated with the binding of ATP and its chemical transformations in the catalytic centers located at the interface of the alpha- and beta-subunits of the enzyme (oligomer complex alpha 3 beta 3 gamma of bovine mitochondrial ATPase). The catalytic cycle of ATP hydrolysis considered in the work includes conformational changes of alpha- and beta-subunits caused by unidirectional rotations of the central gamma-subunit. The results of our calculations are consistent with the idea that the energetically favorable process of ATP binding to the "open" catalytic center of F1-ATPase initiates the rotation of the gamma-subunit followed by ATP hydrolysis in another ("closed") catalytic center of the enzyme.