Structural analysis of class II major histocompatibility complex proteins.

Numerous studies have contributed much data that, taken together, provide considerable insight into the structural features of class II molecules. The putative peptide-binding region has been modeled from the crystal structure of the class I molecule HLA-A2. Mutational analyses and peptide-binding studies support this model. Direct structural studies have established features of the noncovalent association of the alpha and beta chains of class II molecules, and detergents and phospholipids have been shown to affect class II protein structure and/or peptide-binding capacity. Spectroscopic studies have revealed dynamic features of class II molecules in solution, and suggest differences in the overall structures of class I and II molecules that may reflect differences in function.