5DML:
reference: Crystal structure of the homocysteine methyltransferase MmuM from Escherichia coli., Li K, Li G, Bradbury LM, Hanson AD, Bruner SD, Biochem J. 2015 Nov 12. pii: BJ20150980. PMID: 26564203

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).