Water Networks Repopulate Protein–Ligand Interfaces with Temperature. (20th June 2022)

• Record Type: Journal Article
• Authors: Stachowski, Timothy R.; Vanarotti, Murugendra; Seetharaman, Jayaraman; Lopez, Karlo; Fischer, Marcus
• Is Part Of: Angewandte Chemie. Volume 134:Number 31(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-06-20
• Subjects: Conformational Flexibility -- Hsp90 -- Protein–Ligand Interactions -- Room-Temperature Crystallography -- Water Networks; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202112919
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: High‐resolution crystal structures highlight the importance of water networks in protein–ligand interactions. However, as these are typically determined at cryogenic temperature, resulting insights may be structurally precise but not biologically accurate. By collecting 10 matched room‐temperature and cryogenic datasets of the biomedical target Hsp90α, we identified changes in water networks that impact protein conformations at the ligand binding interface. Water repositioning with temperature repopulates protein ensembles and ligand interactions. We introduce Flipper conformational barcodes to identify temperature‐sensitive regions in electron density maps. This revealed that temperature‐responsive states coincide with ligand‐responsive regions and capture unique binding signatures that disappear upon cryo‐cooling. Our results have implications for discovering Hsp90 selective ligands, and, more generally, for the utility of hidden protein and water conformations in drug discovery. Abstract : Cryo‐cooled water molecules block protein motions that impact protein–ligand interactions. Paired cryo and room‐temperature comparisons of ligand‐bound Hsp90α structures show that water networks and protein conformations are more mobile at room temperature. Revealing such alternate conformational states that are masked by cryo‐cooling provides new insights towards drug discovery.