2AKJ:
reference: Structure of spinach nitrite reductase: implications for multi-electron reactions by the iron-sulfur:siroheme cofactor., Swamy U, Wang M, Tripathy JN, Kim SK, Hirasawa M, Knaff DB, Allen JP, Biochemistry. 2005 Dec 13;44(49):16054-63. PMID: 16331965

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