Binding of glycoprotein IIIa-derived peptide 217–231 to fibrinogen and von Willebrand factors and its inhibition by platelet glycoprotein IIb/IIIa complex

doi:10.1016/0167-4838(92)90219-4

Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology

Volume 1119, Issue 3, 12 March 1992, Pages 312-321

Biochimica et Biophy...

https://doi.org/10.1016/0167-4838(92)90219-4 Get rights and content

Abstract

Based on previous reports in the literature and the high homology between platelet glycoprotein (GP) IIIa 217–231 and similar portions of other β subunits of integrin receptors, we hypothesized that this region may participate in ligand binding. Using a polyclonal antibody against GPIIIa 217–231(YC), we tested the interaction of a synthetic peptide representing this region with fibrinogen (Fg), in the enzyme-linked immunosorbent assay (ELISA) system. Results show a calcium-independent, dose-related, direct interaction between GPIIIa 217–231(Y) and immobilized Fg. This peptide also bound to von Willebrand Factor (vWF) and fibronectin (Fn), but did not attach to a 50 kDa Fn fragment which is deficient in the cell attachment site. In addition, purified GPIIb/IIIa displaced GPIIIa 217–231(Y) from Fg and vWF. Binding of ¹²⁵I-GPIIIa 217–231(Y) to Fg coated tubes was inhibited by soluble Fg and by the GPIIb/IIIa complex. We synthesized this peptide with several alterations; similar peptides with Pro-219 replaced with an Ala showed significantly reduced binding to Fg and vWF. The decreased binding of the peptides with Pro-219 substitutes suggests that the confirmation of GPIIIa 217–230 is important for its ability to bind to adhesive ligands. In conclusion, the amino acid rresidues between 217 and 231 of GPIIIa appear to be involved in ligand binding and Pro-219 probably plays a significant role in this interaction.

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^*: Present address: Rhône-Poulenc Rorer Central Research, King of Prussia, PA, U.S.A.

^**: On leave of absence from the Department of Pharmacology, Nicolaus Copernicus Medical School, Cracow, Poland.

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Binding of glycoprotein IIIa-derived peptide 217–231 to fibrinogen and von Willebrand factors and its inhibition by platelet glycoprotein IIb/IIIa complex

Abstract

Blood

Cell

J. Biol. Chem.

Biochim. Biophys. Acta

Cell

J. Biol. Chem.

Anal. Biochem.

J. Biol. Chem.

Cell

J. Biol. Chem.

J. Biol. Chem.

J. Biol. Chem.

J. Biol. Chem.

J. Biol. Chem.

J. Biol. Chem.

J. Biol. Chem.

Science