4LZZ:
reference: Nucleotide-induced asymmetry within ATPase activator ring drives sigma54-RNAP interaction and ATP hydrolysis., Sysoeva TA, Chowdhury S, Guo L, Nixon BT, Genes Dev. 2013 Nov 15;27(22):2500-11. doi: 10.1101/gad.229385.113. PMID: 24240239

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