3h82
From Proteopedia
Crystal structure of the high affinity heterodimer of HIF2 alpha and ARNT C-terminal PAS domains with the artificial ligand THS020
Structural highlights
FunctionARNT_HUMAN Required for activity of the Ah (dioxin) receptor. This protein is required for the ligand-binding subunit to translocate from the cytosol to the nucleus after ligand binding. The complex then initiates transcription of genes involved in the activation of PAH procarcinogens. The heterodimer with HIF1A or EPAS1/HIF2A functions as a transcriptional regulator of the adaptive response to hypoxia. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedHypoxia-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 HIF2alpha (HIF2alpha 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 HIF2alpha 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. Principles of ligand binding within a completely buried cavity in HIF2alpha PAS-B.,Key J, Scheuermann TH, Anderson PC, Daggett V, Gardner KH J Am Chem Soc. 2009 Dec 9;131(48):17647-54. PMID:19950993[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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