Electrostatic interactions in catalytic centers of F<sub>1</sub>-ATPase

Alexandra F. Pogrebnaya; Yury M. Romanovsky; Alexander N. Tikhonov

doi:10.1117/12.518627

13 October 2003 Electrostatic interactions in catalytic centers of F₁-ATPase

Alexandra F. Pogrebnaya, Yury M. Romanovsky, Alexander N. Tikhonov

Proceedings Volume 5068, Saratov Fall Meeting 2002: Optical Technologies in Biophysics and Medicine IV; (2003) https://doi.org/10.1117/12.518627
Event: Saratov Fall Meeting 2002 Laser Physics and Photonics, Spectroscopy, and Molecular Modeling III; Coherent Optics of Ordered and Random Media III, 2002, Saratov, Russian Federation

Abstract

F₁-ATPase is one of the most important enzymes of membrane bioenergetics. F₁-ATPase is the constituent complex that provides the ATP formation from ADP and inorganic phosphate (P_i) at the expense of energy of electrochemical gradient of hydrogen ions generated across the energy transducing mitochondrial, chloroplast or bacterial membrane. F₁-ATPase is a reversible molecular machine that can work as a proton pump due to energy released in the course of ATP hydrolysis (ATPase reaction). The unusual feature of this enzyme is that it operates as a rotary molecular motor. Recently, using the fluorescence microscopy method for the real time visualization of molecular mobility of individual molecules, it was demonstrated directly that the ATP hydrolysis by F₁-ATPase is accompanied by unidirectional rotations of mobile subunits (rotor) of F₁F₀-ATP synthase. In this work, we calculated the contribution of electrostatic interactions between charged groups of a substrate (MgATP), products molecules (MgADP and P_i), and charged amino acid residuals of ATPase molecule to the energy changes associated with the substrate binding and their chemical transformations in the catalytic centers located at the interface of α and β subunits of the enzyme (oligomer complex α₃β₃γ of bovine mitochondria ATPase). A catalytic cycle of ATP hydrolysis considered in our work includes conformational changes of α and β subunits caused by unidirectional rotations of an eccentric γ subunit. The knowledge of energy characteristics and force field in catalytic center of an enzyme in different conformational states may be important for further simulation dynamic properties of ATP synthase complex.

Citation Download Citation

Alexandra F. Pogrebnaya, Yury M. Romanovsky, and Alexander N. Tikhonov "Electrostatic interactions in catalytic centers of F₁-ATPase", Proc. SPIE 5068, Saratov Fall Meeting 2002: Optical Technologies in Biophysics and Medicine IV, (13 October 2003); https://doi.org/10.1117/12.518627

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