3GGF:
reference: Structural comparison of human mammalian ste20-like kinases., Record CJ, Chaikuad A, Rellos P, Das S, Pike AC, Fedorov O, Marsden BD, Knapp S, Lee WH, PLoS One. 2010 Aug 6;5(8):e11905. PMID: 20730082

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