3na0
From Proteopedia
Crystal structure of human CYP11A1 in complex with 20,22-dihydroxycholesterol
Structural highlights
Disease[CP11A_HUMAN] Inherited isolated adrenal insufficiency due to CYP11A1 deficiency;46,XY disorder of sex development - adrenal insufficiency due to CYP11A1 deficiency. The disease is caused by mutations affecting the gene represented in this entry. Function[CP11A_HUMAN] Catalyzes the side-chain cleavage reaction of cholesterol to pregnenolone.[1] [ADX_HUMAN] Participates in the synthesis of thyroid hormones. Essential for the synthesis of various steroid hormones, participates in the reduction of mitochondrial cytochrome P450 for steroidogenesis. Transfers electrons from adrenodoxin reductase to CYP11A1, a cytochrome P450 that catalyzes cholesterol side-chain cleavage.[2] [3] 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 PubMedIn humans, the precursor to all steroid hormones, pregnenolone, is synthesized from cholesterol by an enzyme complex comprising adrenodoxin reductase (AdR), adrenodoxin (Adx), and a cytochrome P450 (P450scc or CYP11A1). This complex not only plays a key role in steroidogenesis, but also has long been a model to study electron transfer, multistep catalysis, and C-C bond cleavage performed by monooxygenases. Detailed mechanistic understanding of these processes has been hindered by a lack of structural information. Here we present the crystal structure of the complex of human Adx and CYP11A1-the first of a complex between a eukaryotic CYP and its redox partner. The structures with substrate and a series of reaction intermediates allow us to define the mechanism underlying sequential hydroxylations of the cholesterol and suggest the mechanism of C-C bond cleavage. In the complex the [2Fe-2S] cluster of Adx is positioned 17.4 A away from the heme iron of CYP11A1. This structure suggests that after an initial protein-protein association driven by electrostatic forces, the complex adopts an optimized geometry between the redox centers. Conservation of the interaction interface suggests that this mechanism is common for all mitochondrial P450s. Structural basis for pregnenolone biosynthesis by the mitochondrial monooxygenase system.,Strushkevich N, Mackenzie F, Cherkesova T, Grabovec I, Usanov S, Park HW Proc Natl Acad Sci U S A. 2011 Jun 2. PMID:21636783[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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