4DAF:
reference: Structure-Based Design of Novel Pyrimido[4,5-c]pyridazine Derivatives as Dihydropteroate Synthase Inhibitors with Increased Affinity., Zhao Y, Hammoudeh D, Yun MK, Qi J, White SW, Lee RE, ChemMedChem. 2012 Mar 13. doi: 10.1002/cmdc.201200049. PMID: 22416048

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