4HPD:
reference: Complexes of ferriheme nitrophorin 4 with low-molecular weight thiol(ate)s occurring in blood plasma., He C, Nishikawa K, Erdem OF, Reijerse E, Ogata H, Lubitz W, Knipp M, J Inorg Biochem. 2013 May;122:38-48. doi: 10.1016/j.jinorgbio.2013.01.012. Epub, 2013 Feb 4. PMID: 23474537

This OCA Structure page
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