2PI5:
reference: Mechanism for de novo RNA synthesis and initiating nucleotide specificity by t7 RNA polymerase., Kennedy WP, Momand JR, Yin YW, J Mol Biol. 2007 Jul 6;370(2):256-68. Epub 2007 Mar 21. PMID: 17512007

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