Regulation of the F0F1-ATP synthase: The conformation of subunit epsilon might be determined by directionality of subunit gamma rotation

Autor(en): Feniouk, BA
Junge, W 
Stichwörter: activation; ADP inhibition; ALPHA(3)BETA(3)GAMMA COMPLEX; ATP synthase; Biochemistry & Molecular Biology; Biophysics; CATALYTIC SITE; Cell Biology; CHLOROPLAST ATP SYNTHASE; ENERGY-DEPENDENT TRANSFORMATION; ESCHERICHIA-COLI F1-ATPASE; MITOCHONDRIAL F1-ATPASE; NONCATALYTIC SITES; PROTON MOTIVE FORCE; protonmotive force; regulation; subunit epsilon; THERMOPHILIC BACILLUS PS3; TIGHTLY BOUND ADP
Erscheinungsdatum: 2005
Herausgeber: WILEY
Journal: FEBS LETTERS
Volumen: 579
Ausgabe: 23
Startseite: 5114
Seitenende: 5118
Zusammenfassung: 
F0F1-ATP synthase couples ATP synthesis/hydrolysis with transmembrane proton transport. The catalytic mechanism involves rotation of the gamma epsilon(similar to 10)-subunits complex relative to the rest of the enzyme. In the absence of protonmotive force the enzyme is inactivated by the tight binding of MgADP. Subunit F also modulates the activity: its conformation can change from a contracted to extended form with C-terminus stretched towards F-1. The latter form ihnibits ATP hydrolysis (but not synthesis). We propose that the directionality of the coiled-coil subunit gamma rotation determines whether subunit E is in contracted or extended form. Block of rotation by MgADP presumably induces the extended conformation of subunit F. This conformation might serve as a safety lock, stabilizing the ADP-inhibited state upon de-energization and preventing spontaneous re-activation and wasteful ATP hydrolysis. The hypothesis merges the known regulatory effects of ADP, protonmotive force and conformational changes of subunit epsilon into a consistent picture. (c) 2005 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
ISSN: 18733468
DOI: 10.1016/j.febslet.2005.08.030

Show full item record

Page view(s)

2
Last Week
0
Last month
0
checked on Feb 26, 2024

Google ScholarTM

Check

Altmetric