4YKB:
reference: Structure of GUN4 from Chlamydomonas reinhardtii., Tarahi Tabrizi S, Langley DB, Harrop SJ, Duff AP, Willows RD, Acta Crystallogr F Struct Biol Commun. 2015 Aug;71(Pt 8):1094-9. doi:, 10.1107/S2053230X15012248. Epub 2015 Jul 29. PMID: 26249706

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