Question

why are mhc molecules able to bind a variety of peptides? 1. the peptide-binding groove of a specific mhc molecule can bind several peptides simultaneously 2. the mhc genes undergo somatic recombination to produce thousands of mhc molecule variants 3. mhc bind very loosely and transiently to peptide antigens, so a wide variety of peptide antigens can bind any specific mhc molecule 4. a small number of amino acids in the peptide antigen bind specifically to complementary pockets in the mhc molecule binding groove

Answer 1

I think it will be 2 Because the composition of the MHC peptide-binding cleft is highly polymorphic, different allelic variants of MHC molecules bind preferentially to different peptides. Amino acids that are critical for the binding of a peptide to a given MHC molecule (the peptide-binding motif) are called anchor residues.