title: ATP synthase that lacks F0a-subunit: isolation, properties, and indication of F0b2-subunits as an anchor rail of a rotating c-ring.
abstract: In a rotary motor F1F0-ATP synthase, F0 works as a proton motor; the oligomer ring of F0c-subunits (c-ring) rotates relative to the F0ab2 domain as protons pass through F0 down the gradient. F0ab2 must exert dual functions during rotation, that is, sliding the c-ring (motor drive) while keeping the association with the c-ring (anchor rail). Here we have isolated thermophilic F1F0(-a) which lacks F0a. F1F0(-a) has no proton transport activity, and F0(-a) does not work as a proton channel. Interestingly, ATPase activity of F1F0(-a) is greatly suppressed, even though its F1 sector is intact. Most likely, F0b2 associates with the c-ring as an anchor rail in the intact F1F0; without F0a, this association prevents rotation of the c-ring (and hence the gamma-subunit), which disables ATP hydrolysis at F1. Functional F1F0 is easily reconstituted from purified F0a and F1F0(-a), and thus F0a can bind to its proper location on F1F0(-a) without a large rearrangement of other-subunits.
authors.affiliation: Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta 4259, Yokohama 226-8503, Japan.
authors.forename: Sakurako
authors.initials: S
authors.lastname: Ono
authors.forename: Nobuhito
authors.initials: N
authors.lastname: Sone
authors.forename: Masasuke
authors.initials: M
authors.lastname: Yoshida
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Suzuki
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000609:Aminoacridines; D001407:Bacillus / Q000201:enzymology / Q000235:genetics; D002463:Cell Membrane Permeability; D004926:Escherichia coli / Q000235:genetics; D005453:Fluorescence; D005456:Fluorescent Dyes; D015870:Gene Expression; D006868:Hydrolysis; D008081:Liposomes; D025261:Mitochondrial Proton-Translocating ATPases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D021122:Protein Subunits / Q000737:chemistry; D017494:Proton Pumps / Q000378:metabolism; D011522:Protons; D013329:Structure-Activity Relationship; D014169:Transformation, Bacterial
chemical_list: D000609:Aminoacridines; D005456:Fluorescent Dyes; D008081:Liposomes; D021122:Protein Subunits; D017494:Proton Pumps; D011522:Protons; C010847:9-amino-6-chloro-2-methoxyacridine; D000255:Adenosine Triphosphate; C474451:F1F0-ATP synthase; D025261:Mitochondrial Proton-Translocating ATPases