3dop
Crystal structure of 5beta-reductase (AKR1D1) in complex with NADP+ and 5beta-dihydrotestosterone, Resolution 2.00A
Structural highlights
DiseaseAK1D1_HUMAN Defects in AKR1D1 are the cause of congenital bile acid synthesis defect type 2 (CBAS2) [MIM:235555; also known as cholestasis with delta(4)-3-oxosteroid 5-beta-reductase deficiency. Patients with this liver disease show absence or low levels of chenodeoxycholic acid and cholic acid in plasma and urine.[1] [2] FunctionAK1D1_HUMAN Efficiently catalyzes the reduction of progesterone, androstenedione, 17-alpha-hydroxyprogesterone and testosterone to 5-beta-reduced metabolites. The bile acid intermediates 7-alpha,12-alpha-dihydroxy-4-cholesten-3-one and 7-alpha-hydroxy-4-cholesten-3-one can also act as substrates. 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 PubMedHuman steroid 5beta-reductase (aldo-keto reductase (AKR) 1D1) catalyzes reduction of Delta(4)-ene double bonds in steroid hormones and bile acid precursors. We have reported the structures of an AKR1D1-NADP(+) binary complex, and AKR1D1-NADP(+)-cortisone, AKR1D1-NADP(+)-progesterone and AKR1D1-NADP(+)-testosterone ternary complexes at high resolutions. Recently, structures of AKR1D1-NADP(+)-5beta-dihydroprogesterone complexes showed that the product is bound unproductively. Two quite different mechanisms of steroid double bond reduction have since been proposed. However, site-directed mutagenesis supports only one mechanism. In this mechanism, the 4-pro-R hydride is transferred from the re-face of the nicotinamide ring to C5 of the steroid substrate. E120, a unique substitution in the AKR catalytic tetrad, permits a deeper penetration of the steroid substrate into the active site to promote optimal reactant positioning. It participates with Y58 to create a "superacidic" oxyanion hole for polarization of the C3 ketone. A role for K87 in the proton relay proposed using the AKR1D1-NADP(+)-5beta-dihydroprogesterone structure is not supported. Structure and catalytic mechanism of human steroid 5beta-reductase (AKR1D1).,Di Costanzo L, Drury JE, Christianson DW, Penning TM Mol Cell Endocrinol. 2008 Sep 19. PMID:18848863[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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