1UJB:
reference: Crystal structure of the protein histidine phosphatase SixA in the multistep His-Asp phosphorelay., Hamada K, Kato M, Shimizu T, Ihara K, Mizuno T, Hakoshima T, Genes Cells. 2005 Jan;10(1):1-11. PMID: 15670209

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