GroEL actively stimulates folding of the endogenous substrate protein PepQ.
Nat Commun
; 8: 15934, 2017 06 30.
Article
em En
| MEDLINE
| ID: mdl-28665408
ABSTRACT
Many essential proteins cannot fold without help from chaperonins, like the GroELS system of Escherichia coli. How chaperonins accelerate protein folding remains controversial. Here we test key predictions of both passive and active models of GroELS-stimulated folding, using the endogenous E. coli metalloprotease PepQ. While GroELS increases the folding rate of PepQ by over 15-fold, we demonstrate that slow spontaneous folding of PepQ is not caused by aggregation. Fluorescence measurements suggest that, when folding inside the GroEL-GroES cavity, PepQ populates conformations not observed during spontaneous folding in free solution. Using cryo-electron microscopy, we show that the GroEL C-termini make physical contact with the PepQ folding intermediate and help retain it deep within the GroEL cavity, resulting in reduced compactness of the PepQ monomer. Our findings strongly support an active model of chaperonin-mediated protein folding, where partial unfolding of misfolded intermediates plays a key role.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Escherichia coli
/
Dipeptidases
/
Escherichia coli
/
Proteínas de Choque Térmico
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Nat Commun
Assunto da revista:
BIOLOGIA
/
CIENCIA
Ano de publicação:
2017
Tipo de documento:
Article
País de afiliação:
Estados Unidos