5Z57:
reference: Structure of the human activated spliceosome in three conformational states., Zhang X, Yan C, Zhan X, Li L, Lei J, Shi Y, Cell Res. 2018 Mar;28(3):307-322. doi: 10.1038/cr.2018.14. Epub 2018 Jan 23. PMID: 29360106

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