5L3X:
reference: Architecture and RNA binding of the human negative elongation factor., Vos SM, Pollmann D, Caizzi L, Hofmann KB, Rombaut P, Zimniak T, Herzog F, Cramer P, Elife. 2016 Jun 10;5. pii: e14981. doi: 10.7554/eLife.14981. PMID: 27282391

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