2NYD:
reference: Structure of a conserved hypothetical protein SA1388 from S. aureus reveals a capped hexameric toroid with two PII domain lids and a dinuclear metal center., Singh Saikatendu K, Zhang X, Kinch L, Leybourne M, Grishin NV, Zhang H, BMC Struct Biol. 2006 Dec 23;6(1):27. PMID: 17187687

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