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Electrospray ionization mass spectrometry identification of fibrinogen Banks Peninsula (γ280Tyr→Cys): a new variant with defective polymerization
Author(s) -
Fellowes Andrew P.,
Brennan Stephen O.,
Ridgway Hayley J.,
Heaton David C.,
George Peter M.
Publication year - 1998
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1046/j.1365-2141.1998.00663.x
Subject(s) - electrospray ionization , chemistry , fibrin , fibrinogen , thrombin , mass spectrometry , polymerization , microbiology and biotechnology , biochemistry , chromatography , platelet , biology , polymer , immunology , organic chemistry
Fibrinogen Banks Peninsula was identified in the mother of a patient referred for investigation following recurrent epistaxis. Coagulation tests revealed prolonged thrombin and reptilase times and a decreased functional fibrinogen level. Thrombin‐catalysed release of fibrinopeptides A and B was normal, and no abnormalities were detected by DNA sequencing of the regions encoding the thrombin cleavage sites in the Aα and Bβ genes. Reducing SDS‐PAGE and reverse‐phase HPLC analysis of purified fibrinogen chains were normal, as was electrospray ionization mass spectrometry (ESI‐MS) analysis of isolated Aα and Bβ chains. However ESI‐MS revealed a mass of 48 345 D for the isolated γ chains, 31 D less than the measured mass of control chains (48 376 D). Since normal and abnormal γ chains were not resolved, this implies a 60–62 D mass decrease in 50% of the molecules. A 60 D decrease was confirmed when DNA sequencing indicated heterozygosity for a mutation of Tyr→Cys at codon 280 of the γ chain gene. Fibrin monomer polymerization revealed a delayed lag phase and reduced final turbidity and although factor XIIIa crosslinking of fibrinogen was normal, it is likely that this delay is due to impaired D:D self association. Recent crystallographic studies show residues γ280 and γ275 make contact across the D:D interface, suggesting a similar mechanism for the polymerization defects in fibrinogens Banks Peninsula and Tokyo II (γ275Arg→Cys).