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Publication Abstract from PubMed

The bacterial chaperonin GroEL-GroES promotes protein folding through ATP-regulated cycles of substrate protein binding, encapsulation, and release. Here, we have used cryoEM to determine structures of GroEL, GroEL-ADP.BeF(3), and GroEL-ADP.AlF(3)-GroES all complexed with the model substrate Rubisco. Our structures provide a series of snapshots that show how the conformation and interactions of non-native Rubisco change as it proceeds through the GroEL-GroES reaction cycle. We observe specific charged and hydrophobic GroEL residues forming strong initial contacts with non-native Rubisco. Binding of ATP or ADP.BeF(3) to GroEL-Rubisco results in the formation of an intermediate GroEL complex displaying striking asymmetry in the ATP/ADP.BeF(3)-bound ring. In this ring, four GroEL subunits bind Rubisco and the other three are in the GroES-accepting conformation, suggesting how GroEL can recruit GroES without releasing bound substrate. Our cryoEM structures of stalled GroEL-ADP.AlF(3)-Rubisco-GroES complexes show Rubisco folding intermediates interacting with GroEL-GroES via different sets of residues.

Structural basis of substrate progression through the bacterial chaperonin cycle.,Gardner S, Darrow MC, Lukoyanova N, Thalassinos K, Saibil HR Proc Natl Acad Sci U S A. 2023 Dec 12;120(50):e2308933120. doi: , 10.1073/pnas.2308933120. Epub 2023 Dec 8. PMID:38064510^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.