4MDR:
reference: Structural and Functional Characterization of Cargo-Binding Sites on the mu4-Subunit of Adaptor Protein Complex 4., Ross BH, Lin Y, Corales EA, Burgos PV, Mardones GA, PLoS One. 2014 Feb 3;9(2):e88147. doi: 10.1371/journal.pone.0088147. eCollection , 2014. PMID: 24498434

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