1lqb
Crystal structure of a hydroxylated HIF-1 alpha peptide bound to the pVHL/elongin-C/elongin-B complexCrystal structure of a hydroxylated HIF-1 alpha peptide bound to the pVHL/elongin-C/elongin-B complex
Structural highlights
FunctionELOC_HUMAN SIII, also known as elongin, is a general transcription elongation factor that increases the RNA polymerase II transcription elongation past template-encoded arresting sites. Subunit A is transcriptionally active and its transcription activity is strongly enhanced by binding to the dimeric complex of the SIII regulatory subunits B and C (elongin BC complex).[1] The elongin BC complex seems to be involved as an adapter protein in the proteasomal degradation of target proteins via different E3 ubiquitin ligase complexes, including the von Hippel-Lindau ubiquitination complex CBC(VHL). By binding to BC-box motifs it seems to link target recruitment subunits, like VHL and members of the SOCS box family, to Cullin/RBX1 modules that activate E2 ubiquitination enzymes.[2] 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 factor-1 (HIF-1) is a transcriptional complex that controls cellular and systemic homeostatic responses to oxygen availability. HIF-1 alpha is the oxygen-regulated subunit of HIF-1, an alpha beta heterodimeric complex. HIF-1 alpha is stable in hypoxia, but in the presence of oxygen it is targeted for proteasomal degradation by the ubiquitination complex pVHL, the protein of the von Hippel Lindau (VHL) tumour suppressor gene and a component of an E3 ubiquitin ligase complex. Capture of HIF-1 alpha by pVHL is regulated by hydroxylation of specific prolyl residues in two functionally independent regions of HIF-1 alpha. The crystal structure of a hydroxylated HIF-1 alpha peptide bound to VCB (pVHL, elongins C and B) and solution binding assays reveal a single, conserved hydroxyproline-binding pocket in pVHL. Optimized hydrogen bonding to the buried hydroxyprolyl group confers precise discrimination between hydroxylated and unmodified prolyl residues. This mechanism provides a new focus for development of therapeutic agents to modulate cellular responses to hypoxia. Structural basis for the recognition of hydroxyproline in HIF-1 alpha by pVHL.,Hon WC, Wilson MI, Harlos K, Claridge TD, Schofield CJ, Pugh CW, Maxwell PH, Ratcliffe PJ, Stuart DI, Jones EY Nature. 2002 Jun 27;417(6892):975-8. Epub 2002 Jun 5. PMID:12050673[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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