3CAQ:
reference: Crystal structures of human Delta4-3-ketosteroid 5beta-reductase (AKR1D1) reveal the presence of an alternative binding site responsible for substrate inhibition., Faucher F, Cantin L, Luu-The V, Labrie F, Breton R, Biochemistry. 2008 Dec 23;47(51):13537-46. PMID: 19075558

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