5JTW:
reference: Structural Basis for the Function of Complement Component C4 within the Classical and Lectin Pathways of Complement., Mortensen S, Kidmose RT, Petersen SV, Szilagyi A, Prohaszka Z, Andersen GR, J Immunol. 2015 Apr 24. pii: 1500087. PMID: 25911760

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