The Solution Structure of Human Coagulation Factor VIIa in Its Complex with Tissue Factor Is Similar to Free Factor VIIa:  A Study of a Heterodimeric Receptor−Ligand Complex by X-ray and Neutron Scattering and Computational Modeling

Biochemistry ◽  
1998 ◽  
Vol 37 (22) ◽  
pp. 8208-8217 ◽  
Author(s):  
Alun W. Ashton ◽  
Mark K. Boehm ◽  
Daniel J. D. Johnson ◽  
Geoffrey Kemball-Cook ◽  
Stephen J. Perkins
Keyword(s):  
Computational Modeling ◽  
Neutron Scattering ◽  
Tissue Factor ◽  
Solution Structure ◽  
Factor Viia ◽  
Coagulation Factor ◽  
Ligand Complex ◽  
Receptor Ligand ◽  
X Ray

scholarly journals The contributions of Ca2+, phospholipids and tissue-factor apoprotein to the activation of human blood-coagulation factor X by activated factor VII

1990 ◽  
Vol 265 (2) ◽  
pp. 327-336 ◽  
Author(s):  
V J J Bom ◽  
R M Bertina
Keyword(s):  
Tissue Factor ◽  
Blood Coagulation ◽  
Reaction Rate ◽  
Factor Viia ◽  
Coagulation Factor ◽  
Fluid Phase ◽  
Fold Increase ◽  
Factor Vii ◽  
Factor X ◽  
Extrinsic Pathway

In the extrinsic pathway of blood coagulation, Factor X is activated by a complex of tissue factor, factor VII(a) and Ca2+ ions. Using purified human coagulation factors and a sensitive spectrophotometric assay for Factor Xa, we could demonstrate activation of Factor X by Factor VIIa in the absence of tissue-factor apoprotein, phospholipids and Ca2+. This finding allowed a kinetic analysis of the contribution of each of the cofactors. Ca2+ stimulated the reaction rate 10-fold at an optimum of 6 mM (Vmax. of 1.1 x 10(-3) min-1) mainly by decreasing the Km of Factor X (to 11.4 microM). In the presence of Ca2+, 25 microM-phospholipid caused a 150-fold decrease of the apparent Km and a 2-fold increase of the apparent Vmax. of the reaction; however, both kinetic parameters increased with increasing phospholipid concentration. Tissue-factor apoprotein contributed to the reaction rate mainly by an increase of the Vmax., in both the presence (40,500-fold) and absence (4900-fold) of phospholipid. The formation of a ternary complex of Factor VIIa with tissue-factor apoprotein and phospholipid was responsible for a 15 million-fold increase in the catalytic efficiency of Factor X activation. The presence of Ca2+ was absolutely required for the stimulatory effects of phospholipid and apoprotein. The data fit a general model in which the Ca2(+)-dependent conformation allows Factor VIIa to bind tissue-factor apoprotein and/or a negatively charged phospholipid surface resulting into a decreased intrinsic Km and an increased Vmax. for the activation of fluid-phase Factor X.

scholarly journals The Eph Tyrosine Kinase Receptors EphB2 and EphA2 Are Novel Proteolytic Substrates of Tissue Factor/Coagulation Factor VIIa

2014 ◽  
Vol 289 (47) ◽  
pp. 32379-32391 ◽  
Author(s):  
Oskar Eriksson ◽  
Margareta Ramström ◽  
Katarina Hörnaeus ◽  
Jonas Bergquist ◽  
Dariush Mokhtari ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Tissue Factor ◽  
Factor Viia ◽  
Coagulation Factor ◽  
Tyrosine Kinase Receptors

Solution structure of phosphorylase kinase studied using small-angle x-ray and neutron scattering

Biochemistry ◽  
1992 ◽  
Vol 31 (2) ◽  
pp. 437-442 ◽  
Author(s):  
S. J. Henderson ◽  
P. Newsholme ◽  
D. B. Heidorn ◽  
R. Mitchell ◽  
P. A. Seeger ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Solution Structure ◽  
Phosphorylase Kinase ◽  
X Ray

scholarly journals Factor VIIa and the extracellular domains of human tissue factor form a compact complex: A study by X-ray and neutron solution scattering

FEBS Letters ◽  
1995 ◽  
Vol 374 (1) ◽  
pp. 141-146 ◽  
Author(s):  
Alun W. Ashton ◽  
Geoffrey Kemball-Cook ◽  
Daniel J.D. Johnson ◽  
David M.A. Martin ◽  
Donogh P. O'Brien ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Human Tissue ◽  
Factor Viia ◽  
X Ray ◽  
Extracellular Domains ◽  
Factor Form

scholarly journals A candidate activation pathway for coagulation factor VII

2019 ◽  
Vol 476 (19) ◽  
pp. 2909-2926
Author(s):  
Tina M. Misenheimer ◽  
Kraig T. Kumfer ◽  
Barbara E. Bates ◽  
Emily R. Nettesheim ◽  
Bradford S. Schwartz
Keyword(s):  
Tissue Factor ◽  
Blood Coagulation ◽  
Factor Viia ◽  
Coagulation Factor ◽  
Factor Ix ◽  
Factor Vii ◽  
Factor X ◽  
Contact Activation ◽  
Coagulation Factor Vii ◽  
Factor Viiia

Abstract The mechanism of generation of factor VIIa, considered the initiating protease in the tissue factor-initiated extrinsic limb of blood coagulation, is obscure. Decreased levels of plasma VIIa in individuals with congenital factor IX deficiency suggest that generation of VIIa is dependent on an activation product of factor IX. Factor VIIa activates IX to IXa by a two-step removal of the activation peptide with cleavages occurring after R191 and R226. Factor IXaα, however, is IX cleaved only after R226, and not after R191. We tested the hypothesis that IXaα activates VII with mutant IX that could be cleaved only at R226 and thus generate only IXaα upon activation. Factor IXaα demonstrated 1.6% the coagulant activity of IXa in a contact activation-based assay of the intrinsic activation limb and was less efficient than IXa at activating factor X in the presence of factor VIIIa. However, IXaα and IXa had indistinguishable amidolytic activity, and, strikingly, both catalyzed the cleavage required to convert VII to VIIa with indistinguishable kinetic parameters that were augmented by phospholipids, but not by factor VIIIa or tissue factor. We propose that IXa and IXaα participate in a pathway of reciprocal activation of VII and IX that does not require a protein cofactor. Since both VIIa and activated IX are equally plausible as the initiating protease for the extrinsic limb of blood coagulation, it might be appropriate to illustrate this key step of hemostasis as currently being unknown.

scholarly journals Funksionele beskrywing van ’n faktor VIIa inhiberende peptied, IP-7, geselekteer deur faagblootleggingstegnologie

2006 ◽  
Vol 25 (4) ◽  
pp. 209-220
Author(s):  
S.M. Meiring ◽  
C.E. Roets ◽  
P.N. Badenhorst
Keyword(s):  
Phage Display ◽  
Tissue Factor ◽  
Factor Viia ◽  
Coagulation Factor ◽  
Competitive Inhibitor ◽  
Factor Vii ◽  
Antithrombotic Agent ◽  
Phage Display Technology ◽  
Current Form ◽  
Coagulation Factor Vii

Die tegniek van faagblootlegging is gebruik om ’n sikliese heptapeptied te selekteer wat met weefselfaktor(WF) kompeteer vir binding aan stollingsfaktor VIIa. Die aminosuurvolgorde van die peptied is Cys-Ala- Trp-Pro-His-Thr-Pro-Asp-Cys (C-AWPHTPD-C) en dit verleng die protrombientyd (PT) op ’n konsentrasie-afhanklike wyse. Die peptied beperk plaatjieklewing aan beide menslike endoteelsel- en weefselfaktormatrikse in ’n vloeikamermodel onder arteriële vloeitoestande. Die peptied funksioneer as ’n volledig mededingende inhibeerder van faktor VIIa met ’n inhibisiekonstante (Ki) van 123,2 μM. In sy huidige vorm is die peptied waarskynlik nie sterk genoeg om verder as antitrombotiese middel ontwikkel te word nie, maar verskillende strategieë kan gevolg word om die werking daarvan te versterk. AbstractFunctional characterisation of a factor VIIa inhibiting peptide, IP-7 selected by phage display technology By using the technique of phage display, we selected a cyclic heptapeptide sequence Cys-Ala-Trp-Pro-His-Thr-Pro-Asp-Cys (C-AWPHTPD-C) that competes with tissue factor for binding to coagulation factor VII. This peptide prolongs the prothrombin time (PT) in a concentration dependent way. It also reduces platelet adhesion to both human endothelial cell and tissue factor matrixes in a flow chamber under arterial flow conditions. Furthermore, it acts as a full competitive inhibitor of factor VIIa with an inhibition constant (Ki) of 123,2 μM. In its current form the peptide is probably not sufficiently potent for development as an antithrombotic agent, but different strategies could be followed to reinforce its performance.

scholarly journals Structural Studies of Overlapping Dinucleosomes in Solution

2019 ◽  
Author(s):  
A. Matsumoto ◽  
M. Sugiyama ◽  
Z. Li ◽  
A. Martel ◽  
L. Porcar ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Neutron Scattering ◽  
Small Angle ◽  
Solution Structure ◽  
Scattering Data ◽  
Mode Analysis ◽  
Conformational Ensemble ◽  
Histone Tails ◽  
Nucleosome Remodeling ◽  
X Ray

AbstractAn overlapping dinucleosome (OLDN) is a structure composed of one hexasome and one octasome and appears to be formed through nucleosome collision promoted by nucleosome remodeling factor(s). In the present study, the solution structure of the OLDN was investigated through integration of small-angle X-ray and neutron scattering (SAXS and SANS, respectively), computer modeling, and molecular dynamics simulations. Starting from the crystal structure, we generated a conformational ensemble based on normal mode analysis, and searched for the conformations that well reproduced the SAXS and SANS scattering curves. We found that inclusion of histone tails, which are not observed in the crystal structure, greatly improved model quality. The obtained structural models suggest that OLDNs adopt a variety of conformations stabilized by histone tails situated at the interface between the hexasome and octasome, simultaneously binding to both the hexasomal and octasomal DNA. In addition, our models define a possible direction for the conformational changes or dynamics, which may provide important information that furthers our understanding of the role of chromatin dynamics in gene regulation.Statement of SignificanceOverlapping dinucleosomes (OLDNs) are intermediate structures formed through nucleosome collision promoted by nucleosome remodeling factor(s). To study the solution structure of OLDNs, a structural library containing a wide variety of conformations was prepared though simulations, and the structures that well reproduced the small angle X-ray and neutron scattering data were selected from the library. Simultaneous evaluation of the conformational variation in the global OLDN structures and in the histone tails is difficult using conventional MD simulations. We overcame this problem by combining multiple simulation techniques, and showed the importance of the histone tails for stabilizing the structures of OLDNs in solution.

scholarly journals The Location of the Active Site of Blood Coagulation Factor VIIa above the Membrane Surface and Its Reorientation upon Association with Tissue Factor

1996 ◽  
Vol 271 (45) ◽  
pp. 28168-28175 ◽  
Author(s):  
Christine D. McCallum ◽  
Raymond C. Hapak ◽  
Pierre F. Neuenschwander ◽  
James H. Morrissey ◽  
Arthur E. Johnson
Keyword(s):  
Tissue Factor ◽  
Blood Coagulation ◽  
Active Site ◽  
Factor Viia ◽  
Membrane Surface ◽  
Coagulation Factor

Aptamer ARC19499 mediates a procoagulant hemostatic effect by inhibiting tissue factor pathway inhibitor

Blood ◽  
2011 ◽  
Vol 117 (20) ◽  
pp. 5514-5522 ◽  
Author(s):  
Emily K. Waters ◽  
Ryan M. Genga ◽  
Michael C. Schwartz ◽  
Jennifer A. Nelson ◽  
Robert G. Schaub ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Tissue Factor Pathway Inhibitor ◽  
Hemophilia A ◽  
Factor Viia ◽  
Factor Xa ◽  
Coagulation Factor ◽  
Factor Ix ◽  
Intrinsic Pathway ◽  
Extrinsic Pathway ◽  
Tissue Factor Pathway

Abstract Hemophilia A and B are caused by deficiencies in coagulation factor VIII (FVIII) and factor IX, respectively, resulting in deficient blood coagulation via the intrinsic pathway. The extrinsic coagulation pathway, mediated by factor VIIa and tissue factor (TF), remains intact but is negatively regulated by tissue factor pathway inhibitor (TFPI), which inhibits both factor VIIa and its product, factor Xa. This inhibition limits clot initiation via the extrinsic pathway, whereas factor deficiency in hemophilia limits clot propagation via the intrinsic pathway. ARC19499 is an aptamer that inhibits TFPI, thereby enabling clot initiation and propagation via the extrinsic pathway. The core aptamer binds tightly and specifically to TFPI. ARC19499 blocks TFPI inhibition of both factor Xa and the TF/factor VIIa complex. ARC19499 corrects thrombin generation in hemophilia A and B plasma and restores clotting in FVIII-neutralized whole blood. In the present study, using a monkey model of hemophilia, FVIII neutralization resulted in prolonged clotting times as measured by thromboelastography and prolonged saphenous-vein bleeding times, which are consistent with FVIII deficiency. ARC19499 restored thromboelastography clotting times to baseline levels and corrected bleeding times. These results demonstrate that ARC19499 inhibition of TFPI may be an effective alternative to current treatments of bleeding associated with hemophilia.

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