A polymorphic pocket at the P10 position contributes to peptide binding specificity in class II MHC proteins.
Zavala-Ruiz Z, Strug I, Anderson MW, Gorski J, Stern LJ. A polymorphic pocket at the P10 position contributes to peptide binding specificity in class II MHC proteins. Chem Biol. 2004 Oct; 11(10):1395-402.