3ENM:
reference: The structure of the MAP2K MEK6 reveals an autoinhibitory dimer., Min X, Akella R, He H, Humphreys JM, Tsutakawa SE, Lee SJ, Tainer JA, Cobb MH, Goldsmith EJ, Structure. 2009 Jan 14;17(1):96-104. PMID: 19141286

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