ATP-dependent substrate transport by the ABC transporter MsbA is proton-coupled.
Nat Commun
; 7: 12387, 2016 08 08.
Article
em En
| MEDLINE
| ID: mdl-27499013
ABSTRACT
ATP-binding cassette transporters mediate the transbilayer movement of a vast number of substrates in or out of cells in organisms ranging from bacteria to humans. Current alternating access models for ABC exporters including the multidrug and Lipid A transporter MsbA from Escherichia coli suggest a role for nucleotide as the fundamental source of free energy. These models involve cycling between conformations with inward- and outward-facing substrate-binding sites in response to engagement and hydrolysis of ATP at the nucleotide-binding domains. Here we report that MsbA also utilizes another major energy currency in the cell by coupling substrate transport to a transmembrane electrochemical proton gradient. The dependence of ATP-dependent transport on proton coupling, and the stimulation of MsbA-ATPase by the chemical proton gradient highlight the functional integration of both forms of metabolic energy. These findings introduce ion coupling as a new parameter in the mechanism of this homodimeric ABC transporter.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Prótons
/
Proteínas de Bactérias
/
Trifosfato de Adenosina
/
Transportadores de Cassetes de Ligação de ATP
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Nat Commun
Assunto da revista:
BIOLOGIA
/
CIENCIA
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
Reino Unido