Title
A congenitally abnormal fibrinogen (Vlissingen) with a 6-base deletion in the gamma-chain gene, causing defective calcium binding and impaired fibrin polymerization
Author
Gaubius Institute TNO
Koopman, J.
Haverkate, F.
Briet, E.
Lord, S.T.
Publication year
1991
Abstract
A congenitally abnormal fibrinogen (Vlissingen) was isolated from the blood of a young woman suffering from massive pulmonary embolism. Fibrinogen Vlissingen showed an abnormal clotting time with both thrombin and Reptilase(TM). The release of the fibrino-peptides A and B by thrombin was normal, but fibrin polymerization was impaired both in the presence and absence of Ca2+ ions. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis performed according to Laemmli the gamma-chain of fibrinogen Vlissingen showed two bands, one normal and one having an apparently lower molecular mass of about 1500 daltons. The previously described protective effect of Ca2+ ions on plasmin degradation of the carboxyl terminus of the gamma-chain of normal fibrinogen was only partially detectable in fibrinogen Vlissingen. In addition the binding of Ca2+ ions was decreased. Fibrinogen Vlissingen bound 2.4 Ca2+ ions per fibrinogen molecule at pH 7.4, whereas normal fibrinogen bound 3.1 Ca2+ ions. At pH 5.8 fibrinogen Vlissingen bound 1.1 Ca2+ ions, whereas normal fibrinogen bound 2.0 Ca2+ ions per molecule fibrinogen in the D-domains, again indicating a structural change in the carboxyl terminus of fibrinogen. The structural defect was determined by sequence analysis of DNA amplified by use of the polymerase chain reaction. Exons VIII, IX, and X of the gamma-chain gene were amplified and the DNA sequence of the amplified fragments was determined. A 6-base deletion was found in 50% of the fragments corresponding to exon VIII, indicating that the patient was heterozygous for the mutation. This deletion codes for amino acids Asn-319 and Asp-320 in the normal fibrinogen gamma-chain. The data indicate that Asn-319 and Asp-320 are crucial for maintaining the integrity of the carboxyl-terminal polymerization sites, the protective effect of Ca2+ ions on plasmin degradation of the carboxyl terminus of the gamma-chain, and the calcium binding domain at the carboxyl terminus of fibrinogen. Chemicals/CAS: Calcium, 7440-70-2; Fibrin, 9001-31-4; fibrinogen Vlissingen; Fibrinogen, 9001-32-5; Fibrinogens, Abnormal; Macromolecular Systems; Oligonucleotide Probes
Subject
Adult
Base Sequence
Calcium
Case Report
Chromosome Deletion
Comparative Study
Fibrin
Fibrinogen
Fibrinogens, Abnormal
Gene Amplification
Human
Kinetics
Macromolecular Systems
Molecular Sequence Data
Mutation
Oligonucleotide Probes
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TNO identifier
280654
ISSN
0021-9258
Source
Journal of Biological Chemistry, 266 (266), 13456-13461
Document type
article