5O9I:
reference: Structural basis for the persistence of homing endonucleases in transcription factor IIB inteins., Iwai H, Mikula KM, Oeemig JS, Zhou D, Li M, Wlodawer A, J Mol Biol. 2017 Oct 18. pii: S0022-2836(17)30498-9. doi:, 10.1016/j.jmb.2017.10.016. PMID: 29055778

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