3g1r
From Proteopedia
Crystal structure of human liver 5beta-reductase (AKR1D1) in complex with NADP and Finasteride. Resolution 1.70 A
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 PubMedThe Delta(4)-3-ketosteroid functionality is present in nearly all steroid hormones apart from estrogens. The first step in functionalization of the A-ring is mediated in humans by steroid 5alpha- or 5beta-reductase. Finasteride is a mechanism-based inactivator of 5alpha-reductase type 2 with subnanomolar affinity and is widely used as a therapeutic for the treatment of benign prostatic hyperplasia. It is also used for androgen deprivation in hormone-dependent prostate carcinoma, and it has been examined as a chemopreventive agent in prostate cancer. The effect of finasteride on steroid 5beta-reductase (AKR1D1) has not been previously reported. We show that finasteride competitively inhibits AKR1D1 with low micromolar affinity but does not act as a mechanism-based inactivator. The structure of the AKR1D1.NADP(+)*finasteride complex determined at 1.7 A resolution shows that it is not possible for NADPH to reduce the Delta(1-2)-ene of finasteride because the cofactor and steroid are not proximal to each other. The C3-ketone of finasteride accepts hydrogen bonds from the catalytic residues Tyr-58 and Glu-120 in the active site of AKR1D1, providing an explanation for the competitive inhibition observed. This is the first reported structure of finasteride bound to an enzyme involved in steroid hormone metabolism. Inhibition of human steroid 5beta-reductase (AKR1D1) by finasteride and structure of the enzyme-inhibitor complex.,Drury JE, Di Costanzo L, Penning TM, Christianson DW J Biol Chem. 2009 Jul 24;284(30):19786-90. Epub 2009 Jun 10. PMID:19515843[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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