Folding behavior of chaperonin-mediated substrate protein

Area of Science:

• Biophysics
• Computational Biology
• Molecular Biology

Background:

• Chaperonin-mediated protein folding is complex, with varied effects on folding rates.
• Understanding the diversity in chaperonin function requires investigating factors like substrate affinity and confinement.

Purpose of the Study:

• To investigate the thermodynamics and kinetics of protein folding within a chaperonin cavity.
• To elucidate the roles of substrate-protein/chaperonin-wall affinity and spatial confinement in modulating folding behavior.

Main Methods:

• Utilized simplified Gō-type models for molecular dynamics simulations.
• Examined folding of an unfrustrated substrate protein encapsulated in a simulated chaperonin cavity.
• Simulated 15 single-site-mutated mutants to validate the model and assess affinity's importance.

Main Results:

• Folding rate enhancement or retardation depends on the interplay between spatial confinement and affinity.
• Stronger affinity generally leads to slower folding, while weaker affinity results in faster folding.
• Inner hydrophobic residues significantly impact folding kinetics more than exterior ones.

Conclusions:

• Chaperonin affinity, in addition to confinement, is a critical factor in substrate protein folding.
• The study provides insights into the folding mechanisms of molecular chaperonin systems.
• Simulated folding rates show good correlation with experimental data, supporting the model's validity.