Image from the RCSB PDB (www.rcsb.org) of PDB ID 4AH2 (Schlundt, A., Gunther, S., Sticht, J., Wieczorek, M., Roske, Y., Heinemann, U., Freund, C.) (2012) Peptide Linkage to the Alpha-Subunit of Mhcii Creates a Stably Inverted Antigen Presentation Complex. J.Mol.Biol. 423: 294