AH 3121 Chapter Notes - Chapter 3: Heat Shock Protein, Thymus, Organ Transplantation
Document Summary
Genes of the mhc locus include: class i, class ii, class iii. Codes for complement proteins c4, factor b, etc. Mhc class i molecules: expressed on all nucleated cells, an alpha heavy chain noncovalently attached to a beta-2 microglobulin light chain protein, amino-terminal domains peptide-binding cleft. Cleft can accommodate peptides 8-10 amino acids long. Each alpha domain consists of about 90 amino acids. Mhc class 1 molecules have 1 transmembrane domain: alpha-1 and alpha-2 are highly variable/polymorphic regions, beta-1 and beta-2 highly invariable. Mhc class ii molecules: expressed mainly on professional apcs. Non-professional apcs can present antigens, but can"t activate a t cell: 2 glycoprotein chains. Beta chain: amino terminal alpha-1 and beta-1 domains. Highly variable region: binding cleft can bind (larger) peptides 10-30 amino acids long, invariant beta-2 domain contains binding site for cd4. Only a cd4 positive t cell can respond. 2 transmembrane domains: alpha-1 and alpha-2 are highly variable/polymorphic regions, beta-1 and beta-2 highly invariable.
