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http://purl.uniprot.org/citations/9261071http://www.w3.org/1999/02/22-rdf-syntax-ns#typehttp://purl.uniprot.org/core/Journal_Citation
http://purl.uniprot.org/citations/9261071http://www.w3.org/1999/02/22-rdf-syntax-ns#typehttp://purl.uniprot.org/core/Journal_Citation
http://purl.uniprot.org/citations/9261071http://www.w3.org/2000/01/rdf-schema#comment"

Background

Mammalian 3 alpha-hydroxysteroid dehydrogenases (3 alpha-HSDs) modulate the activities of steroid hormones by reversibly reducing their C3 ketone groups. In steroid target tissues, 3 alpha-HSDs act on 5 alpha-dihydrotestosterone, a potent male sex hormone (androgen) implicated in benign prostate hyperplasia and prostate cancer. Rat liver 3 alpha-HSD belongs to the aldo-keto reductase (AKR) superfamily and provides a model for mammalian 3 alpha-, 17 beta- and 20 alpha-HSDs, which share > 65% sequence identity. The determination of the structure of 3 alpha-HSD in complex with NADP+ and testosterone (a competitive inhibitor) will help to further our understanding of steroid recognition and hormone regulation by mammalian HSDs.

Results

We have determined the 2.5 A resolution crystal structure of recombinant rat liver 3 alpha-HSD complexed with NADP+ and testosterone. The structure provides the first picture of an HSD ternary complex in the AKR superfamily, and is the only structure to date of testosterone bound to a protein. It reveals that the C3 ketone in testosterone, corresponding to the reactive group in a substrate, is poised above the nicotinamide ring which is involved in hydride transfer. In addition, the C3 ketone forms hydrogen bonds with two active-site residues implicated in catalysis (Tyr55 and His117).

Conclusions

The active-site arrangement observed in the 3 alpha-HSD ternary complex structure suggests that each positional-specific and stereospecific reaction catalyzed by an HSD requires a particular substrate orientation, the general features of which can be predicted. 3 alpha-HSDs are likely to bind substrates in a similar manner to the way in which testosterone is bound in the ternary complex, that is with the A ring of the steroid substrate in the active site and the beta face towards the nicotinamide ring to facilitate hydride transfer. In contrast, we predict that 17 beta-HSDs will bind substrates with the D ring of the steroid in the active site and with the alpha face towards the nicotinamide ring. The ability to bind substrates in only one or a few orientations could determine the positional-specificity and stereospecificity of each HSD. Residues lining the steroid-binding cavities are highly variable and may select these different orientations."xsd:string
http://purl.uniprot.org/citations/9261071http://purl.org/dc/terms/identifier"doi:10.1016/s0969-2126(97)00234-7"xsd:string
http://purl.uniprot.org/citations/9261071http://purl.org/dc/terms/identifier"doi:10.1016/s0969-2126(97)00234-7"xsd:string
http://purl.uniprot.org/citations/9261071http://purl.uniprot.org/core/author"Jez J.M."xsd:string
http://purl.uniprot.org/citations/9261071http://purl.uniprot.org/core/author"Jez J.M."xsd:string
http://purl.uniprot.org/citations/9261071http://purl.uniprot.org/core/author"Lewis M."xsd:string
http://purl.uniprot.org/citations/9261071http://purl.uniprot.org/core/author"Lewis M."xsd:string
http://purl.uniprot.org/citations/9261071http://purl.uniprot.org/core/author"Ma H."xsd:string
http://purl.uniprot.org/citations/9261071http://purl.uniprot.org/core/author"Ma H."xsd:string
http://purl.uniprot.org/citations/9261071http://purl.uniprot.org/core/author"Bennett M.J."xsd:string
http://purl.uniprot.org/citations/9261071http://purl.uniprot.org/core/author"Bennett M.J."xsd:string
http://purl.uniprot.org/citations/9261071http://purl.uniprot.org/core/author"Albert R.H."xsd:string
http://purl.uniprot.org/citations/9261071http://purl.uniprot.org/core/author"Albert R.H."xsd:string
http://purl.uniprot.org/citations/9261071http://purl.uniprot.org/core/author"Penning T.M."xsd:string
http://purl.uniprot.org/citations/9261071http://purl.uniprot.org/core/author"Penning T.M."xsd:string
http://purl.uniprot.org/citations/9261071http://purl.uniprot.org/core/date"1997"xsd:gYear
http://purl.uniprot.org/citations/9261071http://purl.uniprot.org/core/date"1997"xsd:gYear
http://purl.uniprot.org/citations/9261071http://purl.uniprot.org/core/name"Structure"xsd:string
http://purl.uniprot.org/citations/9261071http://purl.uniprot.org/core/name"Structure"xsd:string
http://purl.uniprot.org/citations/9261071http://purl.uniprot.org/core/pages"799-812"xsd:string
http://purl.uniprot.org/citations/9261071http://purl.uniprot.org/core/pages"799-812"xsd:string
http://purl.uniprot.org/citations/9261071http://purl.uniprot.org/core/title"Steroid recognition and regulation of hormone action: crystal structure of testosterone and NADP+ bound to 3 alpha-hydroxysteroid/dihydrodiol dehydrogenase."xsd:string
http://purl.uniprot.org/citations/9261071http://purl.uniprot.org/core/title"Steroid recognition and regulation of hormone action: crystal structure of testosterone and NADP+ bound to 3 alpha-hydroxysteroid/dihydrodiol dehydrogenase."xsd:string
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