Organization of Subunits in the Membrane Domain of the Bovine F-ATPase Revealed by Covalent Cross-linking.
J Biol Chem
; 290(21): 13308-20, 2015 May 22.
Article
em En
| MEDLINE
| ID: mdl-25851905
ABSTRACT
The F-ATPase in bovine mitochondria is a membrane-bound complex of about 30 subunits of 18 different kinds. Currently, â¼85% of its structure is known. The enzyme has a membrane extrinsic catalytic domain, and a membrane intrinsic domain where the turning of the enzyme's rotor is generated from the transmembrane proton-motive force. The domains are linked by central and peripheral stalks. The central stalk and a hydrophobic ring of c-subunits in the membrane domain constitute the enzyme's rotor. The external surface of the catalytic domain and membrane subunit a are linked by the peripheral stalk, holding them static relative to the rotor. The membrane domain contains six additional subunits named ATP8, e, f, g, DAPIT (diabetes-associated protein in insulin-sensitive tissues), and 6.8PL (6.8-kDa proteolipid), each with a single predicted transmembrane α-helix, but their orientation and topography are unknown. Mutations in ATP8 uncouple the enzyme and interfere with its assembly, but its roles and the roles of the other five subunits are largely unknown. We have reacted accessible amino groups in the enzyme with bifunctional cross-linking agents and identified the linked residues. Cross-links involving the supernumerary subunits, where the structures are not known, show that the C terminus of ATP8 extends â¼70 Å from the membrane into the peripheral stalk and that the N termini of the other supernumerary subunits are on the same side of the membrane, probably in the mitochondrial matrix. These experiments contribute significantly toward building up a complete structural picture of the F-ATPase.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fragmentos de Peptídeos
/
Membrana Celular
/
ATPases Mitocondriais Próton-Translocadoras
/
Mitocôndrias
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
2015
Tipo de documento:
Article