Which portion of MHC 1 complex forms the component of antigen presenting part :
Antigen Presenting part of MHC
MHC I/HLAI :
Class 1 molecule consists of a three domains of heavy alpha peptide chain (a1 ; a2; a3) which are non-covalently linked to smaller
β2 microglobulin peptide.
The distal domain (alpha 1 and alpha 2) of MCH 1 have highly variable amino acid sequences and are folded to form a cavity or groove.
Protein antigens are bound to this groove for presentation to CD8 T cells. MHC II/HLA II :
MHC II antigens are heterodimer consisting of an alpha and beta chain. Each chain has two domain proximal one is constant and distal one is variable.
The two distal domain (alpha 1, beta 1) constitute the antigen binding site, for recognition by CD4 T cells.
Both class 1 and class 2 are members of immunoglobulin gene super family.
MHC III /HLA III
§ MHC III are heterogenous they include complement components involved in the formation of C3 convertase, heat shock protein and tumor necrosis factor.
Between alpha 1 – beta 2 microglobulin
Distal part of alpha chain
Proximal part of alpha chain
Between aS and b2 microglobulin