1NXP:
reference: Crystal structure of the response regulator 02 receiver domain, the essential YycF two-component system of Streptococcus pneumoniae in both complexed and native states., Bent CJ, Isaacs NW, Mitchell TJ, Riboldi-Tunnicliffe A, J Bacteriol 2004 May;186(9):2872-9. PMID: 15090529

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