1I55:
reference: Electron tunneling in protein crystals., Tezcan FA, Crane BR, Winkler JR, Gray HB, Proc Natl Acad Sci U S A 2001 Apr 24;98(9):5002-6. PMID: 11296248

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