4JER:
reference: The Hemophore HasA from Yersinia pestis (HasAyp) Coordinates Hemin with a Single Residue, Tyr75, and with Minimal Conformational Change., Kumar R, Lovell S, Matsumura H, Battaile KP, Moenne-Loccoz P, Rivera M, Biochemistry. 2013 Apr 23;52(16):2705-7. doi: 10.1021/bi400280z. Epub 2013 Apr, 11. PMID: 23578210

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