4INX:
reference: Crystallographic Observation of pH-Induced Conformational Changes in the Amyelois transitella Pheromone-Binding Protein AtraPBP1., di Luccio E, Ishida Y, Leal WS, Wilson DK, PLoS One. 2013;8(2):e53840. doi: 10.1371/journal.pone.0053840. Epub 2013 Feb 13. PMID: 23418423

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