title: Identification of a domain in apolipoprotein B-100 that inhibits the procoagulant activity of tissue factor.
abstract: The ability of low-density lipoprotein (LDL) to inhibit the procoagulant activity of tissue factor is mediated by a direct protein-protein interaction involving apolipoprotein (apo) B-100. A lysine-rich sequence within apo B-100 (residues 3121-3217), which we have termed lysine-rich apo B-100-derived (KRAD)-98 peptide, may be responsible for its activity. Within this region, residues 3147-3160 (KRAD-14) contain an exceptionally high proportion of positive amino acids. Both recombinant KRAD-98 and KRAD-14 peptides inhibited the procoagulant activity of tissue factor by preventing the activation of factor VII. KRAD-14 also inhibited the prothrombinase components, factors Xa and V. In comparison with the parent protein (apo B-100), KRAD-14 peptide displayed a 20-fold enhancement in the rate of inhibition, whereas KRAD-98 peptide exhibited a rate closer to that of apo B-100. Mutational analysis of KRAD-14 peptide revealed three adjacent amino acids, alteration of which greatly reduced the inhibitory potential of this peptide. A peptide derived from tissue factor (residues 58-66) was found to act co-operatively with tissue factor itself, but also augmented the inhibition of tissue-factor activity by apo B-100. In conclusion, LDL may be a physiological regulator of haemostatic mechanisms through the interactions of lysine-rich domains of apo B-100 with tissue factor.
authors.affiliation: Department of Biochemistry and Molecular Biology, Royal Free Hospital School of Medicine, Rowland Hill Street, London NW3 2PF, U. K. Camille@RFHCM.AC.UK
authors.forename: C
authors.initials: C
authors.lastname: Ettelaie
authors.forename: N J
authors.initials: NJ
authors.lastname: James
authors.forename: J M
authors.initials: JM
authors.lastname: Adam
authors.forename: K P
authors.initials: KP
authors.lastname: Nicola
authors.forename: B R
authors.initials: BR
authors.lastname: Wilbourn
authors.forename: K R
authors.initials: KR
authors.lastname: Bruckdorfer
mesh_terms: D000595:Amino Acid Sequence; D053299:Apolipoprotein B-100; D001055:Apolipoproteins B / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D003001:Cloning, Molecular; D004926:Escherichia coli; D005165:Factor V / Q000378:metabolism; D005167:Factor VII / Q000378:metabolism; D015942:Factor VIIa / Q000378:metabolism; D005170:Factor X / Q000378:metabolism; D006487:Hemostasis; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism*; D011973:Receptors, LDL / Q000378:metabolism; D013329:Structure-Activity Relationship; D013925:Thromboplastin / Q000037:antagonists & inhibitors*
chemical_list: D053299:Apolipoprotein B-100; D001055:Apolipoproteins B; D009842:Oligopeptides; D010446:Peptide Fragments; D011973:Receptors, LDL; D005165:Factor V; D005167:Factor VII; D005170:Factor X; D013925:Thromboplastin; D015942:Factor VIIa