1Z9P:
reference: Structural basis of heme binding in the Cu,Zn superoxide dismutase from Haemophilus ducreyi., Toro I, Petrutz C, Pacello F, D'Orazio M, Battistoni A, Djinovic-Carugo K, J Mol Biol. 2009 Feb 20;386(2):406-18. Epub 2008 Dec 11. PMID: 19103206

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