scholarly journals Effective electrostatic charge of coagulation factor X in solution and on phospholipid membranes: implications for activation mechanisms and structure–function relationships of the Gla domain

1998 ◽  
Vol 330 (1) ◽  
pp. 533-539 ◽  
Author(s):  
P. Maria McGEE ◽  
Hoa TEUSCHLER ◽  
Jie LIANG
Keyword(s):  
Ionic Strength ◽  
Electrostatic Interactions ◽  
Specific Interaction ◽  
Geometric Analysis ◽  
Factor Xa ◽  
Coagulation Factor ◽  
Reaction Rates ◽  
Phase Cell ◽  
Factor X ◽  
Gla Domain

Electrostatic interactions during activation of coagulation factor X were analysed by comparing effects of ionic strength on reaction rates with predictions of classical electrostatic theory. Geometrical correlations were investigated using alpha-shape-based computations on the crystal structure of Ca-fragment 1 of prothrombin. The ionic strength of the reaction environment was controlled with different univalent salts including NaCl, KCl, CsCl, LiCl, NaI, NaBr and KI. Reactions were assembled in three different environments: aqueous phase, cell membranes and synthetic TF/PS/PC (tissue factor relipidated in 30% phosphatidylserine, 70% phosphatidylcholine) vesicles. Reaction rates were measured at pH 7.2, 4 mM CaCl2 and 33 °C, using chromogenic substrate to follow factor Xa generation. Rates decreased with increasing concentration of univalent salt, and the magnitude of the decrease was independent of salt type. On the basis of electrostatic relationships on PS/PC vesicles, the effective charge on factor X was +1.5, and the PS/factor X stoichiometry was 2.28. Structural analysis of the γ-carboxyglutamic acid (Gla) domain revealed three surface pockets, forming potential sites for Ca2+ binding, with distinct spatial orientations. Interpreted together, the results of the geometric analysis and the measured effective charges suggest an efficient electrostatic mechanism for capture and retention of substrates by procoagulant membranes. Non-specific and delocalized interaction between the membrane and each one of the charged facets of the Gla domain can increase the probability of substrate binding, while allowing rotational and translational mobility of substrate for specific interaction with the enzyme.

Activation of Human Coagulation Factor VIII by Activated Factor X, the Common Product of the Intrinsic and the Extrinsic Pathway of Blood Coagulation

1982 ◽  
Vol 47 (02) ◽  
pp. 096-100 ◽  
Author(s):  
K Mertens ◽  
R M Bertina
Keyword(s):  
Factor Viii ◽  
Human Factor ◽  
Intrinsic Factor ◽  
Factor Xa ◽  
Coagulation Factor ◽  
Factor X ◽  
Extrinsic Factor ◽  
Extrinsic Pathway ◽  
Factor Ixa ◽  
The Common

SummaryThe intrinsic activation of human factor X has been studied in a system consisting of purified factors and in plasma. In both these systems factor Xa stimulated the activation of factor X by factor IXa plus factor VIII This is due to the activation of factor VIII by factor Xa. When this factor Xa is formed via the extrinsic pathway, the extrinsic factor X activator functions as a stimulator of the intrinsic factor X activator.

Coagulation Factor X-Binding Protein fromDeinagkistrodon acutusVenom Is a Gla Domain-Binding Protein†

Biochemistry ◽  
1998 ◽  
Vol 37 (50) ◽  
pp. 17361-17370 ◽  
Author(s):  
Hideko Atoda ◽  
Midori Ishikawa ◽  
Hiroshi Mizuno ◽  
Takashi Morita
Keyword(s):  
Binding Protein ◽  
Coagulation Factor ◽  
Factor X ◽  
Gla Domain

Two parallel prothrombin activator systems in Australian rough-scaled snake, Tropidechis carinatus

2005 ◽  
Vol 93 (01) ◽  
pp. 40-47 ◽  
Author(s):  
Md. Abu Reza ◽  
Sanjay Swarup ◽  
Manjunatha Kini
Keyword(s):  
Blood Coagulation ◽  
Blood Clotting ◽  
Cdna Sequence ◽  
Factor Xa ◽  
Coagulation Factor ◽  
Venom Gland ◽  
Factor X ◽  
Specific Expression ◽  
Life Saving ◽  
Sequence Encoding

SummaryIt is uncommon for similar pathways/systems to be involved in highly divergent functions within single organisms. Earlier, we have shown that trocarin D, a venom prothrombin activator, from the Australian rough-scaled snake Tropidechis carinatus, is structurally and functionally similar to the blood coagulation factor Xa (FXa). The presence of a haemostatic system in these snakes implies that they have two parallel prothrombin activating systems: one in the plasma, that participates in the life saving process of blood clotting and the other in their venom, where it acts as a toxin. Here, we report the complete cDNA sequence encoding the blood coagulation factor X (FX) from the liver of T. carinatus. Deduced T. carinatus FX sequence shows ~80% identity with trocarin D but ~50% identity with the mammalian FX. Our present study confirms the presence of two separate genes – one each for FX and trocarin D, that code for similar proteins in T. carinatus snake. These two genes have different expression sites and divergent uses suggesting that snake venom prothrombin activators have probably evolved by the duplication of the liver FX gene and subsequently marked for tissue-specific expression in the venom gland.

scholarly journals The Low-Density Lipoprotein Receptor-Related Protein (LRP) Mediates Clearance of Coagulation Factor Xa In Vivo

Blood ◽  
1998 ◽  
Vol 91 (2) ◽  
pp. 555-560 ◽  
Author(s):  
Masaaki Narita ◽  
Amy E. Rudolph ◽  
Joseph P. Miletich ◽  
Alan L. Schwartz
Keyword(s):  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Factor Xa ◽  
Coagulation Factor ◽  
Lipoprotein Receptor ◽  
Factor X ◽  
Receptor Associated Protein ◽  
Density Lipoprotein Receptor ◽  
Lipoprotein Receptor Related Protein

Abstract Blood coagulation factor X plays a pivotal role in the clotting cascade. When administered intravenously to mice, the majority of activated factor X (factor Xa) binds to α2-macroglobulin (α2M) and is rapidly cleared from the circulation into liver. We show here that the low-density lipoprotein receptor-related protein (LRP) is responsible for factor Xa catabolism in vivo. Mice overexpressing a 39-kD receptor-associated protein that binds to LRP and inhibits its ligand binding activity displayed dramatically prolonged plasma clearance of 125I-factor Xa. Preadministration of α2M-proteinase complexes (α2M*) also diminished the plasma clearance of125I-factor Xa in a dose-dependent fashion. The clearance of preformed complexes of 125I-factor Xa and α2M was similar to that of 125I-factor Xa alone and was also inhibited by mice overexpressing a 39-kD receptor-associated protein. These results thus suggest that, in vivo, factor Xa is metabolized via LRP after complex formation with α2M.

scholarly journals NMR structure determination of Ixolaris and factor X(a) interaction reveals a noncanonical mechanism of Kunitz inhibition

Blood ◽  
2019 ◽  
Vol 134 (8) ◽  
pp. 699-708 ◽  
Author(s):  
Viviane S. De Paula ◽  
Nikolaos G. Sgourakis ◽  
Ivo M. B. Francischetti ◽  
Fabio C. L. Almeida ◽  
Robson Q. Monteiro ◽  
...  
Keyword(s):  
Factor Xa ◽  
Coagulation Factor ◽  
Structural Basis ◽  
Factor X ◽  
Heparin Binding ◽  
Nmr Structure Determination ◽  
High Resolution Structure ◽  
Function Relationship ◽  
Affinity Interaction ◽  
Relationship Of

Abstract Ixolaris is a potent tick salivary anticoagulant that binds coagulation factor Xa (FXa) and zymogen FX, with formation of a quaternary tissue factor (TF)/FVIIa/ FX(a)/Ixolaris inhibitory complex. Ixolaris blocks TF-induced coagulation and PAR2 signaling and prevents thrombosis, tumor growth, and immune activation. We present a high-resolution structure and dynamics of Ixolaris and describe the structural basis for recognition of FX. Ixolaris consists of 2 Kunitz domains (K1 and K2) in which K2 is strikingly dynamic and encompasses several residues involved in FX binding. This indicates that the backbone plasticity of K2 is critical for Ixolaris biological activity. Notably, a nuclear magnetic resonance–derived model reveals a mechanism for an electrostatically guided, high-affinity interaction between Ixolaris and FX heparin-binding (pro)exosite, resulting in an allosteric switch in the catalytic site. This is the first report revealing the structure-function relationship of an anticoagulant targeting a zymogen serving as a scaffold for TF inhibition.

The Use of Ideal Amphipathic Helical Peptides To Reduce Hemorrhage In Vivo.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3152-3152
Author(s):  
Sophie Charbonneau ◽  
Jorge G. Ganopolsky ◽  
Henry T. Pang ◽  
Pang N. Shek ◽  
Mark D. Blostein
Keyword(s):  
Factor Xa ◽  
Factor X ◽  
Amphipathic Peptide ◽  
In Vivo Experiments ◽  
Factor Ixa ◽  
Carboxyglutamic Acid ◽  
Direct Binding ◽  
Gla Domain ◽  
Acid Domain

Abstract We have previously demonstrated that a 22 amino acid ideal amphipathic peptide (IAP) of K7L15 composition dramatically accelerates both factor IXa and factor Xa activity. In the present work, we investigate the activity of IAP attached to a surface in view of designing a procoagulant surface to reduce hemorrhage. Our results show that IAP maintains its catalytic enhancing properties for factor IXa and factor Xa when attached to a surface. This enhancement is dependent on the presence of the gamma-carboxyglutamic acid domain of factor X, consistent with the hypothesis that IAP behaves as a phospholipid membrane, providing a surface for the assembly of procoagulant enzymes and substrates. To further confirm this hypothesis, we demonstrate direct binding between surface-bound IAP and the Gla domain of factor X using an ELISA-based binding assay. Based on the aforementioned evidence that immobilized IAP enhances procoagulant activity, we conducted in vivo experiments using an ear-bleeding model in rabbits. We incorporated IAP into DuraSeal, a commercially available sealing agent, and found that the addition of IAP decreases the bleeding time in rabbits by 25% (p=0.0065). In conclusion, the above data provide a rationale for designing procoagulant surfaces in vivo. Further evaluation in larger animal models is warranted.

scholarly journals Pathways in the activation of human coagulation factor X

1980 ◽  
Vol 185 (3) ◽  
pp. 647-658 ◽  
Author(s):  
K Mertens ◽  
R M Bertina
Keyword(s):  
Heavy Chain ◽  
Active Form ◽  
Factor Xa ◽  
Coagulation Factor ◽  
Terminal Region ◽  
Factor Vii ◽  
Factor X ◽  
Catalytically Active ◽  
A Site ◽  
Polypeptide Chains

Purified human Factor X (apparent mol.wt. 72000), which consists of two polypeptide chains (mol.wt. 55000 and 19000), was activated by both Russell's-viper venom and the purified physiological activators (Factor VII/tissue factor and Factor IXa/Factor VIII). They all convert Factor X to catalytically active Factor Xa (mol.wt. 54000) by cleaving the heavy chain at a site on the N-terminal region. In the presence of Ca2+ and phospholipid, the Factor Xa formed catalyses (a) the cleavage of a small peptide (mol.wt. 4000) from the C-terminal region of the heavy chain of Factor Xa, resulting in a second active form (mol.wt. 50000), and (b) the cleavage of a peptide containing the active-site serine residue (mol.wt. 13000) from the C-terminal region of the heavy chain of Factor X, resulting in an inactivatable component (mol.wt. 59000). A nomenclature for the various products is proposed.

scholarly journals Group D prothrombin activators from snake venom are structural homologues of mammalian blood coagulation factor Xa

2003 ◽  
Vol 369 (3) ◽  
pp. 635-642 ◽  
Author(s):  
Veena S. RAO ◽  
Jeremiah S. JOSEPH ◽  
R. Manjunatha KINI
Keyword(s):  
Heavy Chain ◽  
Structural Information ◽  
Factor Xa ◽  
Coagulation Factor ◽  
Serine Proteinase ◽  
Single Step ◽  
Step Method ◽  
Factor Va ◽  
Gla Domain ◽  
Group D

Procoagulant venoms of several Australian elapids contain proteinases that specifically activate prothrombin; among these, Group D activators are functionally similar to coagulation factor Xa (FXa). Structural information on this class of prothrombin activators will contribute significantly towards understanding the mechanism of FXa-mediated prothrombin activation. Here we present the purification of Group D prothrombin activators from three Australian snake venoms (Hoplocephalus stephensi, Notechis scutatus scutatus and Notechis ater niger) using a single-step method, and their N-terminal sequences. The N-terminal sequence of the heavy chain of hopsarin D (H. stephensi) revealed that a fully conserved Cys-7 was substituted with a Ser residue. We therefore determined the complete amino acid sequence of hopsarin D. Hopsarin D shows 70% similarity with FXa and 98% similarity with trocarin D, a Group D prothrombin activator from Tropidechis carinatus. It possesses the characteristic Gla domain, two epidermal growth factor-like domains and a serine proteinase domain. All residues important for catalysis are conserved, as are most regions involved in interactions with factor Va and prothrombin. However, there are some structural differences. Unlike FXa, hopsarin D is glycosylated in both its chains: in light-chain residue 52 and heavy-chain residue 45. The glycosylation on the heavy chain is a large carbohydrate moiety adjacent to the active-site pocket. Overall, hopsarin D is structurally and functionally similar to mammalian coagulation FXa.

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