1FIP:
reference: The structure of Fis mutant Pro61Ala illustrates that the kink within the long alpha-helix is not due to the presence of the proline residue., Yuan HS, Wang SS, Yang WZ, Finkel SE, Johnson RC, J Biol Chem 1994 Nov 18;269(46):28947-54. PMID: 7961857

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