4K9J:
reference: Tryptophan-accelerated electron flow across a protein-protein interface., Takematsu K, Williamson H, Blanco-Rodriguez AM, Sokolova L, Nikolovski P, Kaiser JT, Towrie M, Clark IP, Vlcek A, Winkler JR, Gray HB, J Am Chem Soc. 2013 Sep 13. PMID: 24032375

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