CIRCULAR-DICHROISM DETERMINATION OF CLASS-I MHC-PEPTIDE EQUILIBRIUM DISSOCIATION-CONSTANTS

Class I major histocompatibility complex (MHC) molecules bind peptides derived from degraded proteins for display to T cells of the immune s ystem. Peptides bind to MHC proteins with varying affinities, dependin g upon their sequence and length. We demonstrate that the thermal stab ility of the MHC-peptide complex depends directly on peptide binding a ffinity. We use this correlation to develop a convenient method to det ermine peptide dissociation constants by measuring MHC-peptide complex stability using thermal denaturation profiles monitored by circular d ichroism.