2NPP:
reference: Structure of the protein phosphatase 2A holoenzyme., Xu Y, Xing Y, Chen Y, Chao Y, Lin Z, Fan E, Yu JW, Strack S, Jeffrey PD, Shi Y, Cell. 2006 Dec 15;127(6):1239-51. PMID: 17174897

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