1AFS:
reference: Steroid recognition and regulation of hormone action: crystal structure of testosterone and NADP+ bound to 3 alpha-hydroxysteroid/dihydrodiol dehydrogenase., Bennett MJ, Albert RH, Jez JM, Ma H, Penning TM, Lewis M, Structure 1997 Jun 15;5(6):799-812. PMID: 9261071

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