Thromb Haemost 1996; 76(03): 361-368
DOI: 10.1055/s-0038-1650584
Original Article
Schattauer GmbH Stuttgart

Activation of Factor X by Factor VIIa Complexed with Human-mouse Tissue Factor Chimeras Requires Human Exon 3

Carrie H Fang
1   The Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT
,
T-C Lin
1   The Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT
,
Arabinda Guha
2   Th Departments of Medicine and Biochemistry, Mount Sinai School of Medicine, City University of New York, New York, NY, USA
,
Yale Nemerson
2   Th Departments of Medicine and Biochemistry, Mount Sinai School of Medicine, City University of New York, New York, NY, USA
,
William H Konigsberg
1   The Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT
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Publikationsverlauf

Received 03. Juli 1995

Accepted after resubmission 26. April 1996

Publikationsdatum:
26. Juli 2018 (online)

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Summary

In an attempt to define sequence elements in human and mouse tissue factor (TF) that are responsible for the species specificity observed in their interaction with human factor VIIa (HVIIa), we constructed human-mouse chimeric TF cDNAs, inserted them into plasmid vectors, and induced their expression in E.coli. Assays for procoagulant activity were carried out with the resulting E. coli lysates using (HVIIa) human and mouse (MVIIa). The ratio of the procoagulant activities, HVIIa/MVIIa, revealed that human TF exon 3 was essential for activity when the TF:VIIa complex was formed with HVIIa. By ligating the maltose binding protein (MBP) gene to TF cDNAs it was possible to construct, express and purify MBP-TF chimeras as well as to estimate their specific activities. With selected MBP-TF chimeras and HVIIa we determined kinetic parameters for the activation of human factor X. Replacement of exon 3 in human TF cDNA with the corresponding exon from mouse TF cDNA resulted in both lower affinity for HVIIa and failure to convert bound HVIIa into a potent protease