Visualizing GroEL/ES in the act of encapsulating a folding protein.
Cell
; 153(6): 1354-65, 2013 Jun 06.
Article
in En
| MEDLINE
| ID: mdl-23746846
ABSTRACT
The GroEL/ES chaperonin system is required for the assisted folding of many proteins. How these substrate proteins are encapsulated within the GroEL-GroES cavity is poorly understood. Using symmetry-free, single-particle cryo-electron microscopy, we have characterized a chemically modified mutant of GroEL (EL43Py) that is trapped at a normally transient stage of substrate protein encapsulation. We show that the symmetric pattern of the GroEL subunits is broken as the GroEL cis-ring apical domains reorient to accommodate the simultaneous binding of GroES and an incompletely folded substrate protein (RuBisCO). The collapsed RuBisCO folding intermediate binds to the lower segment of two apical domains, as well as to the normally unstructured GroEL C-terminal tails. A comparative structural analysis suggests that the allosteric transitions leading to substrate protein release and folding involve concerted shifts of GroES and the GroEL apical domains and C-terminal tails.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Ribulose-Bisphosphate Carboxylase
/
Protein Folding
/
Chaperonin 10
/
Escherichia coli Proteins
/
Escherichia coli
/
Heat-Shock Proteins
Language:
En
Journal:
Cell
Year:
2013
Type:
Article
Affiliation country:
United States