3Q2O:
reference: Structure of N5-carboxyaminoimidazole ribonucleotide synthase (PurK) from Bacillus anthracis., Tuntland ML, Johnson ME, Fung LW, Santarsiero BD, Acta Crystallogr D Biol Crystallogr. 2011 Oct;67(Pt 10):870-4. Epub 2011, Sep 8. PMID: 21931218

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