| 2NUL: reference: Crystal structure of cytoplasmic Escherichia coli peptidyl-prolyl isomerase: evidence for decreased mobility of loops upon complexation., Edwards KJ, Ollis DL, Dixon NE, J Mol Biol. 1997 Aug 15;271(2):258-65. PMID: 9268657 |
This OCA 
Structure page
uses Jmol,
developed by the Jmol Development Team
(documentation).