Structural Characterization of Heat Shock Protein 90β and Molecular Interactions with Geldanamycin and Ritonavir: A...

Area of Science:

• Oncology
• Molecular Biology
• Drug Discovery

Background:

• Drug repositioning offers a viable strategy for breast cancer treatment.
• Heat Shock Protein 90 beta (Hsp90β) is a key target for inhibiting cancer cell progression.
• The Hsp90β structure features a flexible linker region crucial for its function.

Purpose of the Study:

• To investigate the drug repositioning of ritonavir as an Hsp90β inhibitor for breast cancer therapy.
• To analyze the role of the Hsp90β linker region in the interaction with inhibitors geldanamycin and ritonavir using molecular modeling.
• To compare ritonavir's interaction with Hsp90β to that of geldanamycin and the substrate ATP.

Main Methods:

• Utilized molecular modeling techniques.
• Analyzed the Hsp90β linker region's contribution to protein flexibility and ligand interactions.
• Examined the binding interactions of geldanamycin and ritonavir with Hsp90β.

Main Results:

• The flexible linker region of Hsp90β influences protein motion without disrupting inhibitor binding at the N-terminus.
• Ritonavir demonstrates interactions with the Hsp90β N-terminus, similar to geldanamycin.
• Ritonavir occupies the same pharmacophore zone as ATP, indicating potential competitive inhibition.

Conclusions:

• Ritonavir is a promising candidate for Hsp90β targeted therapy in breast cancer, warranting further investigation.
• The flexibility of the Hsp90β linker region is a significant factor in its chaperone activity and inhibitor interactions.
• Ritonavir's binding profile suggests a mechanism of action comparable to other Hsp90β inhibitors.