2G4X:
reference: On the routine use of soft X-rays in macromolecular crystallography. Part IV. Efficient determination of anomalous substructures in biomacromolecules using longer X-ray wavelengths., Mueller-Dieckmann C, Panjikar S, Schmidt A, Mueller S, Kuper J, Geerlof A, Wilmanns M, Singh RK, Tucker PA, Weiss MS, Acta Crystallogr D Biol Crystallogr. 2007 Mar;63(Pt 3):366-80. Epub 2007, Feb 21. PMID: 17327674

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