Ligand Binding, Unbinding, and Allosteric Effects: Deciphering Small-Molecule Modulation of HSP90

Area of Science:

• Biochemistry
• Molecular Biology
• Structural Biology

Background:

• Heat Shock Protein 90 (HSP90) is crucial for activating client proteins involved in cancer and neurodegeneration.
• Traditional HSP90 inhibitors face challenges due to toxicity.
• Allosteric modulation presents a promising alternative for targeting HSP90.

Purpose of the Study:

• To elucidate the atomistic mechanisms of allosteric ligand recognition by HSP90.
• To understand how allosteric ligands impact HSP90's functional dynamics.
• To explore allosteric stimulators as a potential therapeutic strategy.

Main Methods:

• Utilized advanced computational sampling methods, specifically FunnelMetadynamics.
• Analyzed internal dynamics of structural ensembles from simulations.
• Calculated absolute binding free energy for allosteric ligands.

Main Results:

• Observed multiple binding/unbinding events of allosteric ligands.
• Demonstrated that different binding poses induce distinct HSP90 dynamic states.
• Quantified the absolute binding free energy of allosteric ligands.

Conclusions:

• Allosteric ligand binding/unbinding directly correlates with HSP90 functional motion modulation.
• This study provides atomistic insights into allosteric ligand recognition and its functional consequences.
• Allosteric stimulators offer a viable approach for modulating HSP90 in disease contexts.