TWO-DIMENSIONAL IODOPEPTIDE MAPPING DEMONSTRATES THAT ERYTHROCYTE RH D-POLYPEPTIDES, C-POLYPEPTIDES, AND E-POLYPEPTIDES ARE STRUCTURALLY HOMOLOGOUS BUT NONIDENTICAL

  • 1 October 1988
    • journal article
    • research article
    • Vol. 72  (4) , 1424-1427
Abstract
The 32,000 molecular weight (mol wt) erythrocyte Rh D, c, and E polypeptides were separately purified from cDE/cDE erythrocytes by monoclonal immunoprecipitations and compared by two-dimensional iodopeptide mapping. Digestions of the isolated Rh polypeptides with .alpha.-chymotrypsin revealed a high degree of structural homology between c and E (13/14 iodopeptides were identical) and less striking homology between D and c or E (8/19 identical). The iodopeptide maps of Rh proteins purified by a nonimmunologic protocol from cDE/cDE erythrocytes were virtually identical to the composite pattern (D + c + E) deduced from the individual maps of Rh D, c, and E iodopeptides. Digestions of the isolated Rh polypeptides with trypsin revealed an overall homology of approximately 50% between iodopeptides derived from D, c, and E. These data indicate that the erythrocyte Rh D, c, and E antigens are carried by homologous but distinct molecular species; c and E appear more closely related to each other than to D.