7OIG

CspA-27 cotranslational folding intermediate 3

This is a non-PDB format compatible entry.

Summary for 7OIG

• Entry DOI: 10.2210/pdb7oig/pdb
• EMDB information: 12929
• Descriptor: 23S rRNA, 50S ribosomal protein L9, 50S ribosomal protein L13, ... (57 entities in total)
• Functional Keywords: cotranslational folding, cspa27-3, ribosome
• Biological source: Escherichia coli; More
• Total number of polymer chains: 55
• Total formula weight: 2157631.56

Authors

Agirrezabala, X.,Samatova, E.,Macher, M.,Liutkute, M.,Gil-Carton, D.,Novacek, J.,Valle, M.,Rodnina, M.V. (deposition date: 2021-05-11, release date: 2022-01-19, Last modification date: 2025-03-12)

Primary citation

Agirrezabala, X.,Samatova, E.,Macher, M.,Liutkute, M.,Maiti, M.,Gil-Carton, D.,Novacek, J.,Valle, M.,Rodnina, M.V.
A switch from alpha-helical to beta-strand conformation during co-translational protein folding.
Embo J., 41:e109175-e109175, 2022

PubMed Abstract: Cellular proteins begin to fold as they emerge from the ribosome. The folding landscape of nascent chains is not only shaped by their amino acid sequence but also by the interactions with the ribosome. Here, we combine biophysical methods with cryo-EM structure determination to show that folding of a β-barrel protein begins with formation of a dynamic α-helix inside the ribosome. As the growing peptide reaches the end of the tunnel, the N-terminal part of the nascent chain refolds to a β-hairpin structure that remains dynamic until its release from the ribosome. Contacts with the ribosome and structure of the peptidyl transferase center depend on nascent chain conformation. These results indicate that proteins may start out as α-helices inside the tunnel and switch into their native folds only as they emerge from the ribosome. Moreover, the correlation of nascent chain conformations with reorientation of key residues of the ribosomal peptidyl-transferase center suggest that protein folding could modulate ribosome activity.

PubMed: 34994471
DOI: 10.15252/embj.2021109175

Experimental method

ELECTRON MICROSCOPY (3.2 Å)