3S9N:
reference: How the binding of human transferrin primes the transferrin receptor potentiating iron release at endosomal pH., Eckenroth BE, Steere AN, Chasteen ND, Everse SJ, Mason AB, Proc Natl Acad Sci U S A. 2011 Jul 25. PMID: 21788477

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