F1-ATPase rotation and its inhibition from the viewpoint of solvent entropy

Abstract

We compare the asymmetric packing of F1-ATPase and that of F1-ATPase containing the inhibitor protein IF1 (F1-ATPase(IF1)), which inhibits ATP hydrolysis. To analyze this asymmetric packing, we calculate the solvation entropy, S, of three subcomplexes. Subcomplexes I, II, and III contain βE, βTP, and βDP subunits, respectively. The order of |S| is subcomplex III < subcomplex II < subcomplex I for F1-ATPase, and subcomplex II < subcomplex III < subcomplex I for F1-ATPase(IF1). Thus, the packing of F1-ATPase and F1-ATPase(IF1) is different. We suggest a unified understanding of rotation and its inhibition from the viewpoint of the solvent entropy.