5GMK:
reference: Structure of a yeast catalytic step I spliceosome at 3.4 A resolution., Wan R, Yan C, Bai R, Huang G, Shi Y, Science. 2016 Aug 26;353(6302):895-904. doi: 10.1126/science.aag2235. Epub 2016, Jul 21. PMID: 27445308

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