title: Rotation of artificial rotor axles in rotary molecular motors.
abstract: F1- and V1-ATPase are rotary molecular motors that convert chemical energy released upon ATP hydrolysis into torque to rotate a central rotor axle against the surrounding catalytic stator cylinder with high efficiency. How conformational change occurring in the stator is coupled to the rotary motion of the axle is the key unknown in the mechanism of rotary motors. Here, we generated chimeric motor proteins by inserting an exogenous rod protein, FliJ, into the stator ring of F1or of V1and tested the rotation properties of these chimeric motors. Both motors showed unidirectional and continuous rotation, despite no obvious homology in amino acid sequence between FliJ and the intrinsic rotor subunit of F1or V1These results showed that any residue-specific interactions between the stator and rotor are not a prerequisite for unidirectional rotation of both F1and V1The torque of chimeric motors estimated from viscous friction of the rotation probe against medium revealed that whereas the F1-FliJ chimera generates only 10% of WT F1, the V1-FliJ chimera generates torque comparable to that of V1with the native axle protein that is structurally more similar to FliJ than the native rotor of F1This suggests that the gross structural mismatch hinders smooth rotation of FliJ accompanied with the stator ring of F1.
authors.affiliation: Department of Molecular Biosciences, Kyoto Sangyo University, Kyoto 603-8555, Japan.
authors.forename: Mihori
authors.initials: M
authors.lastname: Baba
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan.
authors.forename: Kousuke
authors.initials: K
authors.lastname: Iwamoto
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan; Department of Functional Molecular Science, School of Physical Sciences, The Graduate University for Advanced Studies , Kanagawa 240-0193, Japan; Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki 444-8787, Japan; Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki 444-8787, Japan.
authors.forename: Ryota
authors.identifier: 0000-0003-0110-5704
authors.initials: R
authors.lastname: Iino
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ueno
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan.
authors.forename: Mayu
authors.initials: M
authors.lastname: Hara
authors.affiliation: Department of Molecular Biosciences, Kyoto Sangyo University, Kyoto 603-8555, Japan.
authors.forename: Atsuko
authors.initials: A
authors.lastname: Nakanishi
authors.affiliation: Department of Molecular Biosciences, Kyoto Sangyo University, Kyoto 603-8555, Japan.
authors.forename: Jun-Ichi
authors.initials: JI
authors.lastname: Kishikawa
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan; hnoji@appchem.t.u-tokyo.ac.jp yokoken@cc.kyoto-su.ac.jp.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Noji
authors.affiliation: Department of Molecular Biosciences, Kyoto Sangyo University, Kyoto 603-8555, Japan; hnoji@appchem.t.u-tokyo.ac.jp yokoken@cc.kyoto-su.ac.jp.
authors.forename: Ken
authors.initials: K
authors.lastname: Yokoyama
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D020409:Molecular Motor Proteins / Q000737:chemistry* / Q000378:metabolism; D011336:Probability; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D006180:Proton-Translocating ATPases / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry; D012399:Rotation; D016415:Sequence Alignment; D013997:Time Factors; D019415:Torque; D025262:Vacuolar Proton-Translocating ATPases / Q000737:chemistry / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D020409:Molecular Motor Proteins; D021122:Protein Subunits; D011994:Recombinant Proteins; D025262:Vacuolar Proton-Translocating ATPases; D006180:Proton-Translocating ATPases
keywords: ATPase; F1; V-ATPase; protein design; rotary molecular motor