4xo6
Crystal structure of human 3-alpha hydroxysteroid dehydrogenase type 3 in complex with NADP+, 5alpha-androstan-3,17-dione and (3beta, 5alpha)-3-hydroxyandrostan-17-oneCrystal structure of human 3-alpha hydroxysteroid dehydrogenase type 3 in complex with NADP+, 5alpha-androstan-3,17-dione and (3beta, 5alpha)-3-hydroxyandrostan-17-one
Structural highlights
Disease[AK1C2_HUMAN] Defects in AKR1C2 are a cause of 46,XY sex reversal type 8 (SRXY8) [MIM:614279]. A disorder of sex development. Affected individuals have a 46,XY karyotype but present as phenotypically normal females.[1] Function[AK1C2_HUMAN] Works in concert with the 5-alpha/5-beta-steroid reductases to convert steroid hormones into the 3-alpha/5-alpha and 3-alpha/5-beta-tetrahydrosteroids. Catalyzes the inactivation of the most potent androgen 5-alpha-dihydrotestosterone (5-alpha-DHT) to 5-alpha-androstane-3-alpha,17-beta-diol (3-alpha-diol). Has a high bile-binding ability.[2] Publication Abstract from PubMedHuman 3alpha-HSD3 (3alpha-hydroxysteroid dehydrogenase type 3) plays an essential role in the inactivation of the most potent androgen 5alpha-DHT (5alpha-dihydrotestosterone). The present study attempts to obtain the important structure of 3alpha-HSD3 in complex with 5alpha-DHT and to investigate the role of 3alpha-HSD3 in breast cancer cells. We report the crystal structure of human 3alpha-HSD3.NADP(+).A-dione (5alpha-androstane-3,17-dione)/epi-ADT (epiandrosterone) complex, which was obtained by co-crystallization with 5alpha-DHT in the presence of NADP(+) Although 5alpha-DHT was introduced during the crystallization, oxidoreduction of 5alpha-DHT occurred. The locations of A-dione and epi-ADT were identified in the steroid-binding sites of two 3alpha-HSD3 molecules per crystal asymmetric unit. An overlay showed that A-dione and epi-ADT were oriented upside-down and flipped relative to each other, providing structural clues for 5alpha-DHT reverse binding in the enzyme with the generation of different products. Moreover, we report the crystal structure of the 3alpha-HSD3.NADP(+).4-dione (4-androstene-3,17-dione) complex. When a specific siRNA (100 nM) was used to suppress 3alpha-HSD3 expression without interfering with 3alpha-HSD4, which shares a highly homologous active site, the 5alpha-DHT concentration increased, whereas MCF7 cell growth was suppressed. The present study provides structural clues for 5alpha-DHT reverse binding within 3alpha-HSD3, and demonstrates for the first time that down-regulation of 3alpha-HSD3 decreases MCF7 breast cancer cell growth. Human 3alpha-hydroxysteroid dehydrogenase type 3: structural clues of 5alpha-DHT reverse binding and enzyme down-regulation decreasing MCF7 cell growth.,Zhang B, Hu XJ, Wang XQ, Theriault JF, Zhu DW, Shang P, Labrie F, Lin SX Biochem J. 2016 Apr 15;473(8):1037-46. doi: 10.1042/BCJ20160083. Epub 2016 Feb, 29. PMID:26929402[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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