3HEF:
reference: Crystal structure of the DNA-recognition component of the bacterial virus Sf6 genome-packaging machine., Zhao H, Finch CJ, Sequeira RD, Johnson BA, Johnson JE, Casjens SR, Tang L, Proc Natl Acad Sci U S A. 2010 Feb 2;107(5):1971-6. Epub 2010 Jan 19. PMID: 20133842

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