5OOB:
reference: Structural basis for mutually exclusive co-transcriptional nuclear cap-binding complexes with either NELF-E or ARS2., Schulze WM, Cusack S, Nat Commun. 2017 Nov 3;8(1):1302. doi: 10.1038/s41467-017-01402-w. PMID: 29101316

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