4DGW:
reference: Structure and assembly of the SF3a splicing factor complex of U2 snRNP., Lin PC, Xu RM, EMBO J. 2012 Feb 7;31(6):1579-90. doi: 10.1038/emboj.2012.7. PMID: 22314233

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