Structural analysis of de novo-designed binders targeting the closed state of HSP90.
Srivastava, D., Singh, S., Boyd, K., Artemyev, N.O.(2026) Structure 
- PubMed: 42887492 Search on PubMed
- DOI: https://doi.org/10.1016/j.str.2026.09.007
- Primary Citation Related Structures: 
13DW, 13DX - PubMed Abstract: 
Heat shock protein 90 (HSP90) assists the folding and maturation of numerous signaling proteins and is an important therapeutic target. Most HSP90 inhibitors target the ATP-binding pocket and disrupt ATP-induced closure, whereas inhibitors targeting the closed state have not been developed. Here, we report de novo-designed protein binders that selectively recognize closed HSP90. Two binders, H2 and H4, have similar folds and affinities for HSP90 but distinct binding kinetics. Cryo-EM structures of HSP90 complexes with H2 and H4 revealed high accuracy of the BindCraft predictions. H2 and H4 compete with p23 at one, but not both, symmetrical p23-binding sites. In HEK293T cells, H2 induced a reduced heat shock response compared with the ATP-site inhibitor 17-DMAG while reducing levels of CDK4, providing functional evidence for HSP90 inhibition. These binders provide tools for probing HSP90 function and potential leads for developing closed-state HSP90 inhibitors.
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA.
Organizational Affiliation: 


