Structure of C-terminal half of two H-2 antigens from cloned mRNA

The classical cell-surface histocompatibility antigens (H-2 antigens in the mouse), known to have key roles in cell-to-cell recognition¹, are encoded by at least three highly polymorphic genes (H-2D, K and L)². Like their human (HLA) counterparts³, H-2 heavy chains span the cell membrane with a short C-terminal cytoplasmic region and an N-terminal extracellular stretch of about 280 amino acids. HLA antigens seem to be organized in three domains containing β-pleated sheets, with disulphide loops within the second and third domains, but the relative scarcity of material has hampered biochemical studies of the H-2 antigens^4-6. We now report the sequencing of plasmids carrying H-2 cDNA as a means of inferring the amino acid sequence of the antigens, and especially of their previously poorly described C-terminal half.