title: Timing of inorganic phosphate release modulates the catalytic activity of ATP-driven rotary motor protein.
abstract: F1-ATPase is a rotary motor protein driven by ATP hydrolysis. The rotary motion of F1-ATPase is tightly coupled to catalysis, in which the catalytic sites strictly obey the reaction sequences at the resolution of elementary reaction steps. This fine coordination of the reaction scheme is thought to be important to achieve extremely high chemomechanical coupling efficiency and reversibility, which is the prominent feature of F1-ATPase among molecular motor proteins. In this study, we intentionally change the reaction scheme by using single-molecule manipulation, and we examine the resulting effect on the rotary motion of F1-ATPase. When the sequence of the products released, that is, ADP and inorganic phosphate, is switched, we find that F1 frequently stops rotating for a long time, which corresponds to inactivation of catalysis. This inactive state presents MgADP inhibition, and thus, we find that an improper reaction sequence of F1-ATPase catalysis induces MgADP inhibition.
authors.affiliation: 1] Department of Applied Chemistry, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan [2] PRESTO, JST, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Rikiya
authors.initials: R
authors.lastname: Watanabe
authors.affiliation: Department of Applied Chemistry, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Noji
mesh_terms: D000244:Adenosine Diphosphate / Q000737:chemistry* / Q000378:metabolism; D055162:Biocatalysis; D007700:Kinetics; D008958:Models, Molecular; D010710:Phosphates / Q000737:chemistry* / Q000378:metabolism; D006180:Proton-Translocating ATPases / Q000737:chemistry* / Q000378:metabolism
chemical_list: D010710:Phosphates; D000244:Adenosine Diphosphate; D006180:Proton-Translocating ATPases