3IZI: Mm-Cpn Rls With Atp

Group II chaperonins are ATP-dependent ring-shaped complexes that bind nonnative polypeptides and facilitate protein folding in archaea and eukaryotes. A built-in lid encapsulates substrate proteins within the central chaperonin chamber. Here, we describe the fate of the substrate during the nucleotide cycle of group II chaperonins. The chaperonin substrate-binding sites are exposed, and the lid is open in both the ATP-free and ATP-bound prehydrolysis states. ATP hydrolysis has a dual function in the folding cycle, triggering both lid closure and substrate release into the central chamber. Notably, substrate release can occur in the absence of a lid, and lid closure can occur without substrate release. However, productive folding requires both events, so that the polypeptide is released into the confined space of the closed chamber where it folds. Our results show that ATP hydrolysis coordinates the structural and functional determinants that trigger productive folding.
PDB ID: 3IZIDownload
MMDB ID: 88329
PDB Deposition Date: 2010/10/29
Updated in MMDB: 2011/05
Experimental Method:
electron microscopy
Resolution: 6.7  Å
Source Organism:
Similar Structures:
Biological Unit for 3IZI: hexadecameric; determined by author
Molecular Components in 3IZI
Label Count Molecule
Proteins (16 molecules)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB