1AF5:
reference: The structure of I-Crel, a group I intron-encoded homing endonuclease., Heath PJ, Stephens KM, Monnat RJ Jr, Stoddard BL, Nat Struct Biol 1997 Jun;4(6):468-76. PMID: 9187655

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