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|3h7w, resolution 1.65Å ()|
|Gene:||EPAS1, HIF2A, Hypoxia Inducible Factor 2 alpha, MOP2 (Homo sapiens), ARNT, Aryl Hydrocarbon Receptor Nuclear Translocator, BHLHE2 (Homo sapiens)|
|Related:||3f1o, 3f1p, 3f1n, 1p97, 1x0o, 2a24, 2b02, 3h82|
Crystal structure of the high affinity heterodimer of HIF2 alpha and ARNT C-terminal PAS domains with the artificial ligand THS017
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 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
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
[EPAS1_HUMAN] Defects in EPAS1 are the cause of familial erythrocytosis type 4 (ECYT4) [MIM:611783]. ECYT4 is an autosomal dominant disorder characterized by increased serum red blood cell mass, elevated hemoglobin concentration and hematocrit, and normal platelet and leukocyte counts.
[EPAS1_HUMAN] Transcription factor involved in the induction of oxygen regulated genes. Binds to core DNA sequence 5'-[AG]CGTG-3' within the hypoxia response element (HRE) of target gene promoters. Regulates the vascular endothelial growth factor (VEGF) expression and seems to be implicated in the development of blood vessels and the tubular system of lung. May also play a role in the formation of the endothelium that gives rise to the blood brain barrier. Potent activator of the Tie-2 tyrosine kinase expression. Activation seems to require recruitment of transcriptional coactivators such as CREBPB and probably EP300. Interaction with redox regulatory protein APEX seems to activate CTAD. [ARNT_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.
About this Structure
- Key J, Scheuermann TH, Anderson PC, Daggett V, Gardner KH. Principles of ligand binding within a completely buried cavity in HIF2alpha PAS-B. J Am Chem Soc. 2009 Dec 9;131(48):17647-54. PMID:19950993 doi:10.1021/ja9073062
- ↑ Furlow PW, Percy MJ, Sutherland S, Bierl C, McMullin MF, Master SR, Lappin TR, Lee FS. Erythrocytosis-associated HIF-2alpha mutations demonstrate a critical role for residues C-terminal to the hydroxylacceptor proline. J Biol Chem. 2009 Apr 3;284(14):9050-8. doi: 10.1074/jbc.M808737200. Epub 2009, Feb 10. PMID:19208626 doi:10.1074/jbc.M808737200
- ↑ Percy MJ, Beer PA, Campbell G, Dekker AW, Green AR, Oscier D, Rainey MG, van Wijk R, Wood M, Lappin TR, McMullin MF, Lee FS. Novel exon 12 mutations in the HIF2A gene associated with erythrocytosis. Blood. 2008 Jun 1;111(11):5400-2. doi: 10.1182/blood-2008-02-137703. Epub 2008, Mar 31. PMID:18378852 doi:10.1182/blood-2008-02-137703
- ↑ Percy MJ, Furlow PW, Lucas GS, Li X, Lappin TR, McMullin MF, Lee FS. A gain-of-function mutation in the HIF2A gene in familial erythrocytosis. N Engl J Med. 2008 Jan 10;358(2):162-8. doi: 10.1056/NEJMoa073123. PMID:18184961 doi:10.1056/NEJMoa073123
- ↑ Percy MJ, Chung YJ, Harrison C, Mercieca J, Hoffbrand AV, Dinardo CL, Santos PC, Fonseca GH, Gualandro SF, Pereira AC, Lappin TR, McMullin MF, Lee FS. Two new mutations in the HIF2A gene associated with erythrocytosis. Am J Hematol. 2012 Apr;87(4):439-42. doi: 10.1002/ajh.23123. Epub 2012 Feb 24. PMID:22367913 doi:10.1002/ajh.23123