5EC6:
reference: Structural analysis of haemoglobin binding by HpuA from the Neisseriaceae family., Wong CT, Xu Y, Gupta A, Garnett JA, Matthews SJ, Hare SA, Nat Commun. 2015 Dec 16;6:10172. doi: 10.1038/ncomms10172. PMID: 26671256

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