A hairpin turn in a class II MHC-bound peptide orients residues outside the binding groove for T cell recognition.
Zavala-Ruiz, Z., Strug, I., Walker, B.D., Norris, P.J., Stern, L.J.(2004) Proc Natl Acad Sci U S A 101: 13279-13284
- PubMed: 15331779 
- DOI: 10.1073/pnas.0403371101
- Primary Citation of Related Structures:  
1SJE, 1SJH - PubMed Abstract: 
T cells generally recognize peptide antigens bound to MHC proteins through contacts with residues found within or immediately flanking the seven- to nine-residue sequence accommodated in the MHC peptide-binding groove. However, some T cells require peptide residues outside this region for activation, the structural basis for which is unknown ...