Membrane protein insertion and proton-motive-force-dependent secretion through the bacterial holo-translocon SecYEG-SecDF-YajC-YidC.
Proc Natl Acad Sci U S A
; 111(13): 4844-9, 2014 Apr 01.
Article
em En
| MEDLINE
| ID: mdl-24550475
ABSTRACT
The SecY/61 complex forms the protein-channel component of the ubiquitous protein secretion and membrane protein insertion apparatus. The bacterial version SecYEG interacts with the highly conserved YidC and SecDF-YajC subcomplex, which facilitates translocation into and across the membrane. Together, they form the holo-translocon (HTL), which we have successfully overexpressed and purified. In contrast to the homo-dimeric SecYEG, the HTL is a hetero-dimer composed of single copies of SecYEG and SecDF-YajC-YidC. The activities of the HTL differ from the archetypal SecYEG complex. It is more effective in cotranslational insertion of membrane proteins and the posttranslational secretion of a ß-barreled outer-membrane protein driven by SecA and ATP becomes much more dependent on the proton-motive force. The activity of the translocating copy of SecYEG may therefore be modulated by association with different accessory subcomplexes SecYEG (forming SecYEG dimers) or SecDF-YajC-YidC (forming the HTL). This versatility may provide a means to refine the secretion and insertion capabilities according to the substrate. A similar modularity may also be exploited for the translocation or insertion of a wide range of substrates across and into the endoplasmic reticular and mitochondrial membranes of eukaryotes.
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Base de dados:
MEDLINE
Assunto principal:
Força Próton-Motriz
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Proteínas de Escherichia coli
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Complexos Multiproteicos
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Escherichia coli
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Proteínas de Membrana
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article