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Title: Principles of Ligand Binding within a Completely Buried Cavity in HIF2[alpha] PAS-B

Abstract

Hypoxia-inducible factors (HIFs) are heterodimeric transcription factors responsible for the metazoan hypoxia response and promote tumor growth, metastasis, and resistance to cancer treatment. The C-terminal Per-ARNT-Sim (PAS) domain of HIF2{alpha} (HIF2{alpha} PAS-B) contains a preformed solvent-inaccessible cavity that binds artificial ligands that allosterically perturb the formation of the HIF heterodimer. To better understand how small molecules bind within this domain, we examined the structures and equilibrium and transition-state thermodynamics of HIF2{alpha} PAS-B with several artificial ligands using isothermal titration calorimetry, NMR exchange spectroscopy, and X-ray crystallography. Rapid association rates reveal that ligand binding is not dependent upon a slow conformational change in the protein to permit ligand access, despite the closed conformation observed in the NMR and crystal structures. Compensating enthalpic and entropic contributions to the thermodynamic barrier for ligand binding suggest a binding-competent transition state characterized by increased structural disorder. Finally, molecular dynamics simulations reveal conversion between open and closed conformations of the protein and pathways of ligand entry into the binding pocket.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1006095
Resource Type:
Journal Article
Journal Name:
J. Am. Chem. Soc.
Additional Journal Information:
Journal Volume: 131; Journal Issue: (48) ; 12, 2009; Journal ID: ISSN 0002-7863
Country of Publication:
United States
Language:
ENGLISH
Subject:
36 MATERIALS SCIENCE; ANOXIA; CALORIMETRY; CONFORMATIONAL CHANGES; CRYSTAL STRUCTURE; CRYSTALLOGRAPHY; NEOPLASMS; PROTEINS; SPECTROSCOPY; THERMODYNAMICS; TITRATION; TRANSCRIPTION FACTORS

Citation Formats

Key, Jason, Scheuermann, Thomas H, Anderson, Peter C, Daggett, Valerie, Gardner, Kevin H, UWASH), and UTSMC). Principles of Ligand Binding within a Completely Buried Cavity in HIF2[alpha] PAS-B. United States: N. p., 2010. Web. doi:10.1021/ja9073062.
Key, Jason, Scheuermann, Thomas H, Anderson, Peter C, Daggett, Valerie, Gardner, Kevin H, UWASH), & UTSMC). Principles of Ligand Binding within a Completely Buried Cavity in HIF2[alpha] PAS-B. United States. https://doi.org/10.1021/ja9073062
Key, Jason, Scheuermann, Thomas H, Anderson, Peter C, Daggett, Valerie, Gardner, Kevin H, UWASH), and UTSMC). 2010. "Principles of Ligand Binding within a Completely Buried Cavity in HIF2[alpha] PAS-B". United States. https://doi.org/10.1021/ja9073062.
@article{osti_1006095,
title = {Principles of Ligand Binding within a Completely Buried Cavity in HIF2[alpha] PAS-B},
author = {Key, Jason and Scheuermann, Thomas H and Anderson, Peter C and Daggett, Valerie and Gardner, Kevin H and UWASH) and UTSMC)},
abstractNote = {Hypoxia-inducible factors (HIFs) are heterodimeric transcription factors responsible for the metazoan hypoxia response and promote tumor growth, metastasis, and resistance to cancer treatment. The C-terminal Per-ARNT-Sim (PAS) domain of HIF2{alpha} (HIF2{alpha} PAS-B) contains a preformed solvent-inaccessible cavity that binds artificial ligands that allosterically perturb the formation of the HIF heterodimer. To better understand how small molecules bind within this domain, we examined the structures and equilibrium and transition-state thermodynamics of HIF2{alpha} PAS-B with several artificial ligands using isothermal titration calorimetry, NMR exchange spectroscopy, and X-ray crystallography. Rapid association rates reveal that ligand binding is not dependent upon a slow conformational change in the protein to permit ligand access, despite the closed conformation observed in the NMR and crystal structures. Compensating enthalpic and entropic contributions to the thermodynamic barrier for ligand binding suggest a binding-competent transition state characterized by increased structural disorder. Finally, molecular dynamics simulations reveal conversion between open and closed conformations of the protein and pathways of ligand entry into the binding pocket.},
doi = {10.1021/ja9073062},
url = {https://www.osti.gov/biblio/1006095}, journal = {J. Am. Chem. Soc.},
issn = {0002-7863},
number = (48) ; 12, 2009,
volume = 131,
place = {United States},
year = {Mon Apr 19 00:00:00 EDT 2010},
month = {Mon Apr 19 00:00:00 EDT 2010}
}