3HDI:
reference: Crystal and solution structures of a prokaryotic M16B peptidase: an open and shut case., Aleshin AE, Gramatikova S, Hura GL, Bobkov A, Strongin AY, Stec B, Tainer JA, Liddington RC, Smith JW, Structure. 2009 Nov 11;17(11):1465-75. PMID: 19913481

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