Comparative analysis by two-dimensional iodopeptide mapping of the RhD
protein and LW glycoprotein
C Bloy, P Hermand, B Cherif-Zahar, HH Sonneborn and JP Cartron
Unite INSERM U76, Institut National de Transfusion Sanguine Paris, France.
The RhD polypeptide and LW glycoprotein were separately immunopurified with
monoclonal antibodies and compared by two-dimensional (2-D) iodopeptide
mapping after digestion with alpha-chymotrypsin. These proteins have
distinct 2-D maps, as seen after 125I-labeling tyrosine residues
(chloramine-T procedure), and even more strikingly after labeling primary
amine residues (Bolton-Hunter procedure). Of the more than 20 iodopeptides
visualized, only five migrated identically when preparations of RhD and LW
were directly compared, suggesting that RhD and LW are different proteins
that may share some common protein domains. N-glycanase treatment of the
iodopeptides did not modify the 2- D map of the RhD protein but greatly
affected the LW map, further indicating that LW, but not RhD, carries
N-linked carbohydrate chains. After deglycosylation the LW map was
different from the RhD map, confirming that the RhD and LW polypeptides are
different proteins. These findings demonstrate that LW is neither a
glycosylated form of Rh protein nor is Rh a precursor of LW.
Volume 75,
Issue 11,
pp. 2245-2249,
06/01/1990
Copyright © 1990 by The American Society of Hematology
