1LQC:
reference: Refined structure of lac repressor headpiece (1-56) determined by relaxation matrix calculations from 2D and 3D NOE data: change of tertiary structure upon binding to the lac operator., Slijper M, Bonvin AM, Boelens R, Kaptein R, J Mol Biol 1996 Jun 21;259(4):761-73. PMID: 8683581

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