1RNL:
reference: Structure of the Escherichia coli response regulator NarL., Baikalov I, Schroder I, Kaczor-Grzeskowiak M, Grzeskowiak K, Gunsalus RP, Dickerson RE, Biochemistry 1996 Aug 27;35(34):11053-61. PMID: 8780507

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