scholarly journals An amino acid polymorphism within the RGD binding domain of platelet membrane glycoprotein IIIa is responsible for the formation of the Pena/Penb alloantigen system.

1992 ◽  
Vol 90 (5) ◽  
pp. 2038-2043 ◽  
Author(s):  
R Wang ◽  
K Furihata ◽  
J G McFarland ◽  
K Friedman ◽  
R H Aster ◽  
...  
Keyword(s):  
Amino Acid ◽  
Binding Domain ◽  
Platelet Membrane ◽  
Membrane Glycoprotein ◽  
Amino Acid Polymorphism ◽  
Platelet Membrane Glycoprotein ◽  
Glycoprotein Iiia

CHARACTERIZATION OF THE VON WILLEBRAND FACTOR-BINDING DOMAIN OF PLATELET MEMBRANE GLYCOPROTEIN Ib

1987 ◽  
Author(s):  
M Handa ◽  
K Titani ◽  
K Takio ◽  
Z M Ruggeri
Keyword(s):  
Von Willebrand Factor ◽  
Binding Domain ◽  
Platelet Membrane ◽  
Membrane Glycoprotein ◽  
Tryptic Fragment ◽  
Amino Terminal ◽  
Platelet Membrane Glycoprotein ◽  
Limited Digestion ◽  
Von Willebrand ◽  
Willebrand Factor

We have previously obtained immunochemical evidence that the von Willebrand factor (vWF)-binding domain of the platelet membrane glycoprotein (GP) Ib is located near the amino terminus of the a subunit (Journal of Biological Chemistry 261: 12579-12585, 1986). We have now determined the complete amino acid sequence of the 45 kDa tryptic fragment of glycocalicin that contains this domain. Purified glycocalicin was subjected to limited digestion with trypsin and the proteolytic fragments were separated by size-exclusion high-pressure liquid chromatography. Two fragments of 45 kDa and 84 kDa, respectively, were obtained under nonreducing conditions. After reduction and S-carboxymethylation, the 84 kDa fragment was unchanged, while the 45 kDa fragment yielded two new fragments, one of 35 kDa and the other of 7 kDa. This finding proves the existence of a trypsin cleavage site within a disulfide loop. Two primary sets of overlapping fragments were obtained by cleavage of the carboxymethylated protein at methionyl and lysyl bonds following treatment with cyanogen bromide and Achromobacter protease I, respectively. Additional fragments were obtained by treatment of glycocalicin with Staphylococcus aureus V8 protease and Serratia marcescens protease. Analysis of all these fragments provided data that allowed determination of the sequence of the amino terminal 299 residues of the GP Ib a-chain. This includes the 45 kDa tryptic fragment containing the vWF-binding domain. This 299-residue sequence, corresponding approximately to two thirds of the α-chain polypeptide, is largely hydrophobic and contains only two N-linked and one O-linked carbohydrate chains. A hydrophilic region exists between residues 215-299, with a cluster of ten negatively charged residues at 269-287. This area is likely to attract positively charged molecules. The hydrophilic, highly glycosylated (at Ser/Thr residues) region corresponding to the previously described "macroglycopeptide" begins at residue 292. The determined sequence of glycocalicin contains a region with seven repeats, indicative of gene duplication, and is highly homologous to human leucine-rich α2-glycoprotein.

An additional HpaII polymorphism in exon 2 of the human platelet membrane glycoprotein IIIa gene

1994 ◽  
Vol 93 (3) ◽  
pp. 353-354 ◽  
Author(s):  
Bruno Perichon ◽  
Sylvie Clemenceau ◽  
Alain Romand ◽  
Jacques Elion ◽  
Cecile Kaplan ◽  
...  
Keyword(s):  
Human Platelet ◽  
Platelet Membrane ◽  
Membrane Glycoprotein ◽  
Exon 2 ◽  
Platelet Membrane Glycoprotein ◽  
Glycoprotein Iiia

scholarly journals Thrombin-induced platelet membrane glycoprotein IIb and IIIa complex formation. An electron microscope study.

1981 ◽  
Vol 154 (4) ◽  
pp. 1058-1068 ◽  
Author(s):  
M J Polley ◽  
L L Leung ◽  
F Y Clark ◽  
R L Nachman
Keyword(s):  
Complex Formation ◽  
Keyhole Limpet Hemocyanin ◽  
Human Platelets ◽  
Platelet Membrane ◽  
Macromolecular Complex ◽  
Membrane Glycoprotein ◽  
Platelet Surface ◽  
Platelet Membrane Glycoprotein ◽  
Normal Platelet ◽  
Glycoprotein Iiia

The topographic relationships of platelet membrane glycoprotein IIb and glycoprotein IIIa have been studied in stimulated and unstimulated human platelets using immunoelectron microscopy. An indirect approach with ferritin-conjugated goat anti-rabbit gamma-globulin was used to localize the rabbit antibody to glycoprotein IIIa. The second ultrastructural label was keyhole limpet hemocyanin conjugated directly to antibody to glycoprotein IIb. Using the double labels, it was demonstrated that glycoprotein IIb and glycoprotein IIIa were distributed randomly in the unstimulated platelet membrane. After platelet stimulation with thrombin, large clusters of glycoprotein IIb-glycoprotein IIIa complexes were formed. No complex formation between glycoprotein Ib and glycoprotein IIb was observed in control experiments. These observations suggest that thrombin stimulation initiates the specific glycoprotein IIb-glycoprotein IIIa macromolecular complex formation on the platelet surface, which may act as the active fibrinogen-binding site required for normal platelet aggregation.

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