4TWB:
reference: Structure of dimeric, recombinant Sulfolobus solfataricus phosphoribosyl diphosphate synthase: a bent dimer defining the adenine specificity of the substrate ATP., Andersen RW, Leggio LL, Hove-Jensen B, Kadziola A, Extremophiles. 2015 Jan 21. PMID: 25605536

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