1KU2:
reference: Structure of the bacterial RNA polymerase promoter specificity sigma subunit., Campbell EA, Muzzin O, Chlenov M, Sun JL, Olson CA, Weinman O, Trester-Zedlitz ML, Darst SA, Mol Cell 2002 Mar;9(3):527-39. PMID: 11931761

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