4KW7:
reference: A disulfide-bond cascade mechanism for arsenic(III) S-adenosylmethionine methyltransferase., Marapakala K, Packianathan C, Ajees AA, Dheeman DS, Sankaran B, Kandavelu P, Rosen BP, Acta Crystallogr D Biol Crystallogr. 2015 Mar 1;71(Pt 3):505-15. doi:, 10.1107/S1399004714027552. Epub 2015 Feb 26. PMID: 25760600

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