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Titolo:
Coupling H+ transport to rotary catalysis in F-type ATP synthases: Structure and organization of the transmembrane rotary motor
Autore:
Fillingame, RH; Jiang, W; Dmitriev, OY;
Indirizzi:
Univ Wisconsin, Sch Med, Dept Biomol Chem, Madison, WI 53706 USA Univ Wisconsin Madison WI USA 53706 pt Biomol Chem, Madison, WI 53706 USA
Titolo Testata:
JOURNAL OF EXPERIMENTAL BIOLOGY
fascicolo: 1, volume: 203, anno: 2000,
pagine: 9 - 17
SICI:
0022-0949(200001)203:1<9:CHTTRC>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
C-SUBUNIT OLIGOMER; ESCHERICHIA-COLI; SUPPRESSOR MUTATIONS; MOLECULAR MACHINE; MEMBRANE DOMAIN; CROSS-LINKING; ALPHA-SUBUNIT; GAMMA-SUBUNIT; F-0 SECTOR; 2ND STALK;
Keywords:
ATP synthase; proton transport; rotary motor; subunit c; nuclear magnetic resonance; F-o structure; cross-linking; molecular modelling; Escherichia coli;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
51
Recensione:
Indirizzi per estratti:
Indirizzo: Fillingame, RH Univ Wisconsin, Sch Med, Dept Biomol Chem, Madison, WI 53706 USA Univ Wisconsin Madison WI USA 53706 Madison, WI 53706 USA
Citazione:
R.H. Fillingame et al., "Coupling H+ transport to rotary catalysis in F-type ATP synthases: Structure and organization of the transmembrane rotary motor", J EXP BIOL, 203(1), 2000, pp. 9-17

Abstract

H+-transporting F1Fo-type ATP synthases utilize a transmembrane Hf potential to drive ATP formation by a rotary catalytic mechanism. ATP is formed inalternating beta subunits of the extramembranous F-1 sector of the enzyme,synthesis being driven by rotation of the gamma subunit in the center of the F-1 molecule between the alternating catalytic sites. The H+ electrochemical potential is thought to drive gamma subunit rotation by first couplingH+ transport to rotation of an oligomeric rotor of c subunits within the transmembrane F-o sector. The gamma subunit is forced to turn with the c(12)oligomeric rotor as a result of connections between subunit c and the gamma and epsilon subunits of F-1 In this essay, we will review recent studies on the Escherichia coli F-o sector. The monomeric structure of subunit c, determined by nuclear magnetic resonance (NMR), is discussed first and used as a basis for the rest of the review. A model for the structural organization of the c(12) oligomer in F-o, deduced from extensive cross-linking studies and by molecular modeling, is then described. The interactions between the the a(1)b(2) 'stator' subcomplex of F-o and the c(12) oligomer are thenconsidered. A functional interaction between transmembrane helix 4 of subunit a (aTMH-4) and transmembrane helix 2 of subunit c (cTMH-2) during the proton-release step from Asp61 on cTMH-2 is suggested. Current a-c cross-linking data can only be explained by helix-helix swiveling or rotation duringthe proton transfer steps. A model that mechanically links helix rotation within a single subunit c to the incremental 30 degrees rotation of the c(12) oligomer is proposed. In the final section, the structural interactions between the surface residues of the c(12) oligomer and subunits epsilon andgamma are considered. A molecular model for the binding of subunit epsilon. between the exposed, polar surfaces of two subunits c in the oligomer is proposed on the basis of cross-linking data and the NMR structures of the individual subunits.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 21/01/20 alle ore 07:00:57