Molecular weight diversity among murine class I antigens: Both the mature cell surface forms and the unglycosylated polypeptides vary significantly in molecular weight

The molecular weights of the fully glycosylated cell surface form and the unglycosylated polypeptide of five murine class I antigens (H-2K^b, D^b, TL, Qa-1.1, and Qa-2) were compared by SDS-PAGE. Significant molecular weight diversity was observed for both forms among these molecules. The size of the fully glycosylated forms ranged from approximately 52,000 daltons (H-2D^b) to 41,000 daltons (Qa-2), whereas the unglycosylated polypeptides ranged from 43,000 daltons (H-2K^b and TL) to 33,000 daltons (Qa-2). The magnitude of the size variation observed in the unglycosylated polypeptides implies that there are differences in the gene organization, RNA processing or post-translational modifications of various class I glycoproteins.