2P0B:
reference: The crystal structure of the pentahaem c-type cytochrome NrfB and characterization of its solution-state interaction with the pentahaem nitrite reductase NrfA., Clarke TA, Cole JA, Richardson DJ, Hemmings AM, Biochem J. 2007 Aug 15;406(1):19-30. PMID: 17521287

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