Thromb Haemost 1997; 78(06): 1510-1515
DOI: 10.1055/s-0038-1665443
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Peptide-specific Antibodies as Pro\bes of the Topography of the Ca2+-binding Motifs in αIIbβ3 [*]

Jolanta Niewiarowska
1   The Department of Biophysics, Medical University in Lodz, Poland
,
Mariola Świderska
1   The Department of Biophysics, Medical University in Lodz, Poland
,
Tadeusz Majewski
2   Department of Chemistry, University of Warsaw, Poland
,
Czesław S Cierniewski
1   The Department of Biophysics, Medical University in Lodz, Poland
3   Center for Microbiology and Virology, Poland
4   Polish Academy of Sciences, Lodz, Poland
› Institutsangaben
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Publikationsverlauf

Received 05. 1997

Accepted after resubmission 04. August 1997

Publikationsdatum:
12. Juli 2018 (online)

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Summary

Antibodies against synthetic peptides corresponding to four Ca2+- binding motifs of the αIIb subunit have been obtained and used as molecular probes to analyze the topography of the αIIbβ3 complex. The specificity of the antibodies has been characterized by ELISA and Western immunoblotting in terms of binding capacity and affinity to the isolated αIIbβ3 and its αIIb subunit. Our data suggest that: (a) all four Ca2+-binding motifs of the αIIb are partially exposed on the surface of the intact molecule and accessible to antipeptide antibodies. However, they are not in close vicinity to the ligand recognition domain since the antibodies do not produce complete inhibition of platelet aggregation, (b) The conformation of amino acid stretches which form the second Ca2+-binding motif of αIIb is particularly dependent upon the presence of cation, and this region undergoes significant conformational alterations upon Ca2+ expulsion.

*This work was supported in part by the grant PAN/HHS-96-242 from the US-Polish Maria Sklodowska-Curie Joint Fund II, the grant 15195-543001 from Howard Hughes Medical Institute, and PECO project ERBCIPDCT 940247