title: Common variation in the C-terminal region of the fibrinogen beta-chain: effects on fibrin structure, fibrinolysis and clot rigidity.
abstract: Fibrinogen BbetaArg448Lys is a common polymorphism, positioned within the carboxyl terminus of the Bbeta-chain of the molecule. Studies suggest that it is associated with severity of coronary artery disease and development of stroke. The effects of the amino acid substitution on clot structure remains controversial, and the aim of this study was to investigate the effect(s) of this polymorphism on fibrin clot structure using recombinant techniques. Permeation, turbidity, and scanning electron microscopy showed that recombinant Lys448 fibrin had a significantly more compact structure, with thin fibers and small pores, compared with Arg448. Clot stiffness, measured by means of a novel method using magnetic tweezers, was significantly higher for the Lys448 compared with the Arg448 variant. Clots made from recombinant protein variants had similar lysis rates outside the plasma environment, but when added to fibrinogen-depleted plasma, the fibrinolysis rates for Lys448 were significantly slower compared with Arg448. This study demonstrates for the first time that clots made from recombinant BbetaLys448 fibrinogen are characterized by thin fibers and small pores, show increased stiffness, and appear more resistant to fibrinolysis. Fibrinogen BbetaArg448Lys is a primary example of common genetic variation with a significant phenotypic effect at the molecular level.
authors.affiliation: Academic Unit of Molecular Vascular Medicine, Leeds Institute for Genetics, Health and Therapeutics, University of Leeds, UK.
authors.forename: Ramzi
authors.initials: R
authors.lastname: Ajjan
authors.forename: Bernard C B
authors.initials: BC
authors.lastname: Lim
authors.forename: Kristina F
authors.initials: KF
authors.lastname: Standeven
authors.forename: Robert
authors.initials: R
authors.lastname: Harrand
authors.forename: Sarah
authors.initials: S
authors.lastname: Dolling
authors.forename: Fladia
authors.initials: F
authors.lastname: Phoenix
authors.forename: Richard
authors.initials: R
authors.lastname: Greaves
authors.forename: Radwa H
authors.initials: RH
authors.lastname: Abou-Saleh
authors.forename: Simon
authors.initials: S
authors.lastname: Connell
authors.forename: D Alastair M
authors.initials: DA
authors.lastname: Smith
authors.forename: John W
authors.initials: JW
authors.lastname: Weisel
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Grant
authors.forename: Robert A S
authors.initials: RA
authors.lastname: Ariëns
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D003324:Coronary Artery Disease / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D005337:Fibrin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D005340:Fibrinogen / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D005342:Fibrinolysis / Q000235:genetics; D006801:Humans; D008958:Models, Molecular; D011110:Polymorphism, Genetic; D017434:Protein Structure, Tertiary / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020521:Stroke / Q000235:genetics / Q000378:metabolism / Q000473:pathology
chemical_list: C115499:BBeta fibrinogen; D011994:Recombinant Proteins; D005337:Fibrin; D005340:Fibrinogen