1CR1:
reference: Crystal structure of the helicase domain from the replicative helicase-primase of bacteriophage T7., Sawaya MR, Guo S, Tabor S, Richardson CC, Ellenberger T, Cell 1999 Oct 15;99(2):167-77. PMID: 10535735

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