title: Torque transmission mechanism via DELSEED loop of F1-ATPase.
abstract: F1-ATPase (F1) is an ATP-driven rotary motor in which the three catalytic β subunits in the stator ring sequentially induce the unidirectional rotation of the rotary γ subunit. Many lines of evidence have revealed open-to-closed conformational transitions in the β subunit that swing the C-terminal domain inward. This conformational transition causes a C-terminal protruding loop with conserved sequence DELSEED to push the γ subunit. Previous work, where all residues of DELSEED were substituted with glycine to disrupt the specific interaction with γ and introduce conformational flexibility, showed that F1 still rotated, but that the torque was halved, indicating a remarkable impact on torque transmission. In this study, we conducted a stall-and-release experiment on F1 with a glycine-substituted DELSEED loop to investigate the impact of the glycine substitution on torque transmission upon ATP binding and ATP hydrolysis. The mutant F1 showed a significantly reduced angle-dependent change in ATP affinity, whereas there was no change in the equilibrium for ATP hydrolysis. These findings indicate that the DELSEED loop is predominantly responsible for torque transmission upon ATP binding but not for that upon ATP hydrolysis.
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, University of Tokyo, Tokyo, Japan; PRESTO, Japan Science and Technology Agency, Tokyo, Japan; CREST, Japan Science and Technology Agency, Tokyo, Japan.
authors.forename: Rikiya
authors.initials: R
authors.lastname: Watanabe
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, University of Tokyo, Tokyo, Japan.
authors.forename: Kazuma
authors.initials: K
authors.lastname: Koyasu
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, University of Tokyo, Tokyo, Japan.
authors.forename: Huijuan
authors.initials: H
authors.lastname: You
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, University of Tokyo, Tokyo, Japan.
authors.forename: Mizue
authors.initials: M
authors.lastname: Tanigawara
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, University of Tokyo, Tokyo, Japan; CREST, Japan Science and Technology Agency, Tokyo, Japan. Electronic address: hnoji@appchem.t.u-tokyo.ac.jp.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Noji
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D006868:Hydrolysis; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D006180:Proton-Translocating ATPases / Q000737:chemistry* / Q000378:metabolism; D019415:Torque
chemical_list: D000255:Adenosine Triphosphate; D006180:Proton-Translocating ATPases