Symmetric GroEL-GroES complexes can contain substrate simultaneously in both GroEL rings

Area of Science:

• Molecular Biology
• Protein Folding
• Chaperone Proteins

Background:

• GroEL and GroES are molecular chaperones crucial for protein folding.
• Understanding the mechanism of GroEL-GroES action is vital for protein homeostasis.

Purpose of the Study:

• To investigate the formation and structure of GroEL-GroES-rhodanese complexes.
• To explore the role of these complexes in the protein folding cycle.

Main Methods:

• Native electrophoresis to identify GroEL-GroES-rhodanese complexes.
• Electron microscopy for structural analysis.
• Neuronal networks and multivariate statistical analysis for particle classification.

Main Results:

• Formation of symmetric GroEL14(GroES7)2 complexes with rhodanese.
• Classification of complexes into three populations based on substrate occupancy in GroEL cavities.
• Observation of substrate within complexes under functional conditions.

Conclusions:

• Symmetric GroEL-GroES complexes with rhodanese are active intermediates in protein folding.
• Simultaneous use of both GroEL rings may increase protein folding efficiency.