Anticoagulant mechanism of factor IX/factor X-binding protein isolated from the venom of Trimeresurus flavoviridis.

Anticoagulant mechanism of the coagulation factor IX/factor X-binding protein (IX/X-bp) isolated from the venom of Trimeresurus flavoviridis was investigated. IX/X-bp had no effect on the amidase activity of factor Xa measured with a synthetic peptide substrate Boc-Leu-Gly-Arg-pNA. Prothrombin activation by factor Xa without cofactors, such as factor Va and phospholipids, was only slightly influenced by IX/X-bp.

Adenovirus serotype 5 hexon mediates liver gene transfer.

Adenoviruses are used extensively as gene transfer agents, both experimentally and clinically. However, targeting of liver cells by adenoviruses compromises their potential efficacy. In cell culture, the adenovirus serotype 5 fiber protein engages the coxsackievirus and adenovirus receptor (CAR) to bind cells.

Characterization of a monoclonal antibody B1 that recognizes phosphorylated Ser-158 in the activation peptide region of human coagulation factor IX.

Blood coagulation factor IX (FIX) undergoes various post-translational modifications such as gamma-carboxylation and glycosylation. Non-phosphorylated recombinant FIX has been reported to rapidly disappear from plasma, indicating that phosphorylation of FIX plays an important role in the physiological activity of this coagulation factor. In this study, we characterized the human FIX activation peptide (AP) using a monoclonal antibody that recognizes phosphorylated Ser-158 in the AP region.

Snake venom vascular endothelial growth factors (VEGFs) exhibit potent activity through their specific recognition of KDR (VEGF receptor 2).

Vascular endothelial growth factor (VEGF165) exhibits multiple effects via the activation of two distinct endothelial receptor tyrosine kinases: Flt-1 (fms-like tyrosine kinase-1) and KDR (kinase insert domain-containing receptor). KDR shows strong ligand-dependent tyrosine phosphorylation in comparison with Flt-1 and mainly mediates the mitogenic, angiogenic, and permeability-enhancing effects of VEGF165. Here we show the isolation of two VEGFs from viper venoms and the characterization of their unique biological properties.

Calcium-binding analysis and molecular modeling reveal echis coagulation factor IX/factor X-binding protein has the Ca-binding properties and Ca ion-independent folding of other C-type lectin-like proteins.

Many biologically active heterodimeric proteins of snake venom consist of two C-type lectin-like subunits. One of these proteins, habu IX/X-bp, is a Gla domain-binding protein whose subunits both bind to a Ca2+ ion, with a total of two Ca2+-binding sites. The molecular modeling and Ca2+-binding analysis of echis IX/X-bp revealed that it lacks one of two Ca2+-binding sites, though the folding of this subunit is conserved.

Crystal structure of an anticoagulant protein in complex with the Gla domain of factor X.

The gamma-carboxyglutamic acid (Gla) domain of blood coagulation factors is responsible for Ca2+-dependent phospholipid membrane binding. Factor X-binding protein (X-bp), an anticoagulant protein from snake venom, specifically binds to the Gla domain of factor X. The crystal structure of X-bp in complex with the Gla domain peptide of factor X at 2.

Purification, cDNA cloning and characterization of the vascular apoptosis-inducing protein, HV1, from Trimeresurus flavoviridis.

Hemorrhagic snake venom induces apoptosis in vascular endothelial cells (VEC). In previous reports, we described the purification and cDNA cloning from Crotalus atrox of a vascular apoptosis-inducing protein (VAP1) that specifically induces apoptosis in vascular endothelial cells. We report here the purification and cDNA cloning of another vascular apoptosis-inducing protein, HV1, from crude venom of Trimeresurus flavoviridis.

Genetic and molecular mechanisms of age regulation (homeostasis) of blood coagulation.

Blood coagulation plays a critical role not only in hemostasis but also in many physiological and pathological conditions. Epidemiological studies have shown that blood coagulation capacity in humans increases with age. Towards understanding the underlying mechanisms, the age regulation of factor IX, a key blood coagulation factor, was extensively studied.

Crystal structure of flavocetin-A, a platelet glycoprotein Ib-binding protein, reveals a novel cyclic tetramer of C-type lectin-like heterodimers.

Snake venom contains a number of the hemostatically active C-type lectin-like proteins, which affect the interaction between von Willebrand factor (vWF) and the platelet glycoprotein (GP) Ib or platelet receptor to inhibit/induce platelet activation. Flavocetin-A (FL-A) is a high-molecular mass C-type lectin-like protein (149 kDa) isolated from the habu snake venom. FL-A binds with high affinity to the platelet GP Ibalpha-subunit and functions as a strong inhibitor of vWF-dependent platelet aggregation.

Crystallization and preliminary x-ray studies of flavocetin-A, a platelet glycoprotein Ib-binding protein from the habu snake venom.

Flavocetin-A (FL-A) is a platelet glycoprotein Ib-binding protein, a high molecular mass oligomer (149 kDa) of C-type lectin-like subunits alpha and beta isolated from the habu snake venom. Purified FL-A crystallized in the tetragonal space group I4 with unit-cell dimensions a = b = 121.0, c = 63.

Crystal structure of coagulation factor IX-binding protein from habu snake venom at 2.6 A: implication of central loop swapping based on deletion in the linker region.

Coagulation factor IX-binding protein (IX-bp) isolated from the venom of the habu snake (Trimeresurus flavoviridis) is a disulfide-linked heterodimer consisting of homologous subunits A and B. The structure of IX-bp has been solved by X-ray crystallography at 2.6 A resolution to a crystallographic R -value of 0.

Coagulation factor X-binding protein from Deinagkistrodon acutus venom is a Gla domain-binding protein.

Factor IX/factor X-binding protein (IX/X-bp) is an anticoagulant isolated from the venom of Trimeresurus flavoviridis (habu snake) and binds predominantly to factor IX. In this study, we isolated IX/X-bp-like proteins from the venom of Deinagkistrodon acutus (hundred pace snake) with binding characteristics different from those of IX/X-bp. The complete amino acid sequence and binding characteristics of the main anticoagulant protein, named X-bp, were investigated.

cDNA cloning of a heterogeneous two-chain anticoagulant protein IX-bp.

IX-bp and IX/X-bp are heterogeneous two-chain anticoagulant proteins isolated from the venom of habu snake, Trimeresurus flavoviridis. The amino acid sequence of one (B chain) of their two chains is identical. We recently reported the cloning of cDNA encoding the B chain and that of the A chain of IX/X-bp.

Structure of coagulation factors IX/X-binding protein, a heterodimer of C-type lectin domains.

Coagulation factors IX/X-binding protein is an intertwined dimer with a central loop projecting into the adjoining subunit. Excluding this loop, each subunit has a fold similar to rat mannose-binding protein.

cDNA cloning of IX/X-BP, a heterogeneous two-chain anticoagulant protein from snake venom.

IX/X-bp is an anticoagulant protein isolated from the venom of the habu snake (Trimeresurus flavoviridis). It is a heterogeneous two-chain protein linked by an interchain S-S bond. We prepared a cDNA library from the venom gland of the habu snake in the vector pSPORT1.

Blood coagulation factor IX-binding protein from the venom of Trimeresurus flavoviridis: purification and characterization.

The coagulation factor IX/factor X-binding protein (IX/X-bp) from the venom of Trimeresurus flavoviridis is a heterogeneous two-chain protein, and the structure of each chain is similar to that of the carbohydrate-recognition domain of C-type lectins, such as asialoglycoprotein receptors, pancreatic stone protein, and the Fc epsilon receptor for immunoglobulin E. Analysis of the binding properties of IX/X-bp revealed that it binds to the gamma-carboxyglutamic acid (Gla)-containing domains of factors IX and X [Atoda, H. et al.

Regulation of the tertiary structure and function of coagulation factor IX by magnesium (II) ions.

The indispensable role of Ca2+ ions in the maintenance of the functional tertiary structures of vitamin K-dependent coagulation factors has been definitively established but the participation of Mg2+ ions, another alkaline-earth metal that is present abundantly in blood plasma, in such a process is not yet understood. We show here that the Ca(2+)-stabilized conformation of coagulation factor IX undergoes a further conformational change upon binding of Mg2+ ions using three independent structural probes. The probes we used were (i) IX/X-bp, a snake venom anticoagulant that recognizes the Gla domains in coagulation factors IX and X, (ii) conformation-specific polyclonal antibodies against bovine factor IX, and (iii) monoclonal antibodies against the Gla domain of human factor IX.

cDNA cloning and deduced amino acid sequence of prothrombin activator (ecarin) from Kenyan Echis carinatus venom.

The complete amino acid sequence of ecarin is deduced from the nucleotide sequence of a cDNA clone isolated by screening a venomous gland cDNA library of Kenyan Echis carinatus. The cDNA sequence with 2379 base pairs encodes an open reading frame of 616 amino acids with a remarkable sequence homology to the putative precursor protein of trigramin from Trimeresurus gramineus venom (61% identity) and a large hemorrhagin, jararhagin, from the pit viper Bothrops jararaca venom (62% identity). Thus, ecarin, as well as jararhagin and trigramin, is translated as a precursor protein, which may be processed posttranslationally.

Binding properties of the coagulation factor IX/factor X-binding protein isolated from the venom of Trimeresurus flavoviridis.

The binding properties of the coagulation factor IX/factor X-binding anticoagulant protein (IX/X-bp) isolated from the venom of Trimeresurus flavoviridis (habu snake) were investigated with an enzyme-linked immunosorbent assay. The half-maximal binding and maximal binding of IX/X-bp to both factors IX and X were observed at concentrations of Ca2+ ions of 0.4 mM and 1 mM, respectively.

Isolation and characterization of an anticoagulant protein homologous to botrocetin from the venom of Bothrops jararaca.

We previously isolated a unique anticoagulant protein named IX/X-bp (factor IX/factor X-binding protein) from the venom of the habu snake Trimeresurus flavoviridis. We recently determined its primary structure and found that this protein had a structure homologous to the carbohydrate-recognition domains of C-type lectins. Most interestingly, a high homology was found between this protein and botrocetin, an inducer of platelet agglutination found in the venom of the jararaca snake Bothrops jararaca.

Arrangement of the disulfide bridges in a blood coagulation factor IX/factor X-binding protein from the venom of Trimeresurus flavoviridis.

Blood coagulation factor IX/factor X-binding protein (IX/X-bp) is a two-chain anticoagulant protein that was isolated from the venom of Trimeresurus flavoviridis. The amino acid sequence of IX/X-bp is homologous to the sequences of C-type lectin-like proteins, such as asialoglycoprotein receptor, tetranectin, and the low-affinity Fc epsilon receptor of immunoglobulin E. The amino acid composition and amino acid sequence of cystine-containing peptides, formed as a result of enzymatic digestion of CNBr-generated fragments of IX/X-bp, were analyzed to determine the location of the seven disulfide bridges in the protein.

The primary structure of coagulation factor IX/factor X-binding protein isolated from the venom of Trimeresurus flavoviridis. Homology with asialoglycoprotein receptors, proteoglycan core protein, tetranectin, and lymphocyte Fc epsilon receptor for immunoglobulin E.

An anticoagulant protein, factor IX/factor X-binding protein (IX/X-bp), isolated from the venom of Trimeresurus flavoviridis, binds with factor IX and factor X in the presence of Ca2+ with a 1 to 1 stoichiometry (Atoda, H., and Morita, T. (1989) J.

Crystallization and preliminary X-ray study of blood coagulation factor IX/factor X-binding protein with anticoagulant activity from Habu snake venom.

Crystals of a blood anticoagulant from the venom of the Habu snake, Trimeresurus flavoviridis, have been obtained using ammonium sulfate by the vapor diffusion method. The crystals belong to the orthorhombic space group P2(1)2(1)2 with cell dimensions a = 172 A, b = 86 A, c = 65 A, and diffract to at least 4.0 A resolution.

A novel blood coagulation factor IX/factor X-binding protein with anticoagulant activity from the venom of Trimeresurus flavoviridis (Habu snake): isolation and characterization.

Using affinity chromatography on a column of factor X-Cellulofine, we have isolated a novel blood coagulation factor X-binding protein with anticoagulant activity from the venom of Trimeresurus flavoviridis (Habu snake). This anticoagulant protein was also purified by chromatography on Sephadex G-75 and S-Sepharose Fast Flow. The yield of the purified protein was approximately 16 mg from 400 mg of crude venom.