A monoclonal antibody recognizing the activation domain of protein C in its calcium‐free conformation

FEBS Letters

Gaussem, Pascale¹  Aiach, Martine¹  Vincenot, Anne¹  Pittet, Jean-Louis² 

[1] INSERM U 428, Faculté de Pharmacie, 4 avenue de l'Observatoire, F-75270 Paris Cedex 06, France;bioMérieux laboratories, Hemostasis Department, F-69280 Marcy-l'Etoile, France

关键词: Protein C;    Monoclonal antibody;    Activation peptide;    Epitope mapping;    Calcium ion;   

DOI  :  10.1016/S0014-5793(98)00802-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

A monoclonal antibody (mAb) binding to protein C (PC) heavy chain but not to activated PC was found to inhibit PC activation by free thrombin, suggesting that epitope involved the activation site. Using a set of overlapping synthetic peptides, we confirmed that this mAb recognizes the sequence encompassing the thrombin cleavage site (¹⁶⁵QVDPRLI¹⁷¹). Surprisingly, epitope was only accessible in the absence of calcium, half-maximal inhibition of mAb binding occurring at 100 μM Ca²⁺. Thus, our antibody provides direct evidence that conformation and/or accessibility of the activation site differ between the apo and Ca²⁺-stabilized conformers of PC.

【 授权许可】

Unknown