MICR 3230 Chapter 8: Chapter 8 notes
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Anigen presening molecules (classical mhc do, nonclassical do not) 3 external domains: 1 2 and 3 (90aa each) 1 and 2 form pepide closed ended binding groove (loor or sheets and walls of chains), holds 8-10aa pepides (shorter than class 2) Present on all nucleated cells in the body. Hydrophobic anchor residues on both ends of pepide, causing middle to arch out (to interact with tcr); these are conserved so muliple pepides can bind same mhc1. 1 and 1 form open ended binding groove, holds 8-13aa pepides (longer than class 1) Conserved residues distributed evenly along pepide (doesn"t arch outward) Polycistronic mrna (locus encodes 3 classes mhc genes) Class 3 genes encode complement and inlammaion proteins which do not present anigens. Organizaion of mhc genes difers between mice and humans. Mhc is highly polymorphic with many alleles; a set of alleles is a haplotype. Polymorphism has funcional relevance: diferences clustered in binding groove.