1JYW:
reference: A structural view of the action of Escherichia coli (lacZ) beta-galactosidase., Juers DH, Heightman TD, Vasella A, McCarter JD, Mackenzie L, Withers SG, Matthews BW, Biochemistry 2001 Dec 11;40(49):14781-94. PMID: 11732897

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