Endo S, Morikawa Y, Kudo Y, Suenami K, Matsunaga T, Ikari A, Hara A. Human dehydrogenase/reductase SDR family member 11 (DHRS11) and aldo-keto reductase 1C isoforms in comparison: Substrate and reaction specificity in the reduction of 11-keto-C
19-steroids.
J Steroid Biochem Mol Biol 2020;
199:105586. [PMID:
31926269 DOI:
10.1016/j.jsbmb.2020.105586]
[Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 01/07/2020] [Accepted: 01/07/2020] [Indexed: 10/25/2022]
Abstract
Recent studies have shown that an adrenal steroid 11β-hydroxy-4-androstene-3,17-dione serves as the precursor to androgens, 11-ketotestosterone and 11-ketodihydrotestosterone (11KDHT). The biosynthetic pathways include the reduction of 3- and 17-keto groups of the androgen precursors 11-keto-C19-steroids, which has been reported to be mediated by three human enzymes; aldo-keto reductase (AKR)1C2, AKR1C3 and 17β-hydroxysteroid dehydrogenase (HSD) type-3. To explore the contribution of the enzymes in the reductive metabolism, we kinetically compared the substrate specificity for 11-keto-C19-steroids among purified recombinant preparations of four AKRs (1C1, 1C2,1C3 and 1C4) and DHRS11, which shows 17β-HSD activity. Although AKR1C1 did not reduce the 11-keto-C19-steroids, AKR1C3 and DHRS11 reduced 17-keto groups of 11-keto-4-androstene-3,17-dione, 11-keto-5α-androstane-3,17-dione (11K-Adione) and 11-ketoandrosterone with Km values of 5-28 μM. The 3-keto groups of 11KDHT and 11K-Adione were reduced by AKR1C4 (Km 1 μM) more efficiently than by AKR1C2 (Km 5 and 8 μM, respectively). GC/MS analysis of the products showed that DHRS11 acts as 17β-HSD, and that AKR1C2 and AKR1C4 are predominantly 3α-HSDs, but formed a minor 3β-metabolite from 11KDHT. Since DHRS11 was thus newly identified as 11-keto-C19-steroid reductase, we also investigated its substrate-binding mode by molecular docking and site-directed mutagenesis of Thr163 and Val200, and found the following structural features: 1). There is a space that accommodates the 11-keto group of the 11-keto-C19-steroids in the substrate-binding site. 2) Val200 is a critical determinant for exhibiting the strict 17β-HSD activity of the enzyme, because the Val200Leu mutation resulted in both significant impairment of the 17β-HSD activity and emergence of 3β-HSD activity towards 5α-androstanes including 11KDHT.
Collapse