4OB1:
reference: The active site sulfenic acid ligand in nitrile hydratases can function as a nucleophile., Martinez S, Wu R, Sanishvili R, Liu D, Holz R, J Am Chem Soc. 2014 Jan 29;136(4):1186-9. doi: 10.1021/ja410462j. Epub 2014 Jan, 13. PMID: 24383915

This OCA Structure page
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