Major histocompatibility complex class I H-2K^b^ (H-2K^b^)

The Major histocompatibility complex class I H-2K^b^ (H-2K^b^) is a mouse MHC class I molecule composed of a polymorphic heavy α-chain (approximately 350 amino acids) non-covalently associated with the invariant β2-microglobulin light chain (99 amino acids), forming a peptide-binding groove between α1 and α2 domains flanked by α-helices and an eight-stranded β-sheet floor.[1][4][5][8] This groove binds short peptides (typically 8-9 residues) derived from intracellular proteins, such as viral antigens like the vesicular stomatitis virus nucleoprotein (VSV N52-59 octapeptide), positioning them for recognition by cytotoxic CD8+ T-cell receptors (TCRs).[1][2][3][7][9] Crystal structures at 2.8 Å resolution reveal allele-specific architecture that dictates peptide anchor residues and hydrogen bonds, primarily involving main-chain atoms of the peptide with conserved tyrosines (e.g., Tyr-84, Tyr-171) at groove ends, ensuring stable presentation.[1][2][4] H-2K^b^ shares high structural homology with human HLA class I molecules (rms deviation ~1.9 Å for α-chains), supporting conserved functions in adaptive immunity where the peptide-MHC complex interfaces with TCRs for immune surveillance.[1][3][8] In disease contexts, it plays a key role in anti-viral responses and tumor immunosurveillance, though allelic variations influence peptide repertoire and immune evasion in infections or cancer.[1][2][3][8][9] While not a direct small-molecule drug target, its structure informs immunotherapeutic strategies like peptide vaccines or TCR therapies targeting specific alleles.[1][2][5]

Other names

H-2KbMHC class I H-2K^b^