A5036209779- Blood Coagulation and Thrombosis Mechanisms
- Hemophilia Treatment and Research
- Coagulation, Bradykinin, Polyphosphates, and Angioedema
- Protease and Inhibitor Mechanisms
- Venomous Animal Envenomation and Studies
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Platelet Disorders and Treatments
- Vitamin K Research Studies
- Enzyme Production and Characterization
- Peptidase Inhibition and Analysis
- Hemoglobin structure and function
- Atrial Fibrillation Management and Outcomes
- Enzyme Structure and Function
- Heparin-Induced Thrombocytopenia and Thrombosis
- Lipid Membrane Structure and Behavior
- Venous Thromboembolism Diagnosis and Management
- Protein Interaction Studies and Fluorescence Analysis
- Cancer-related gene regulation
- Radioactive contamination and transfer
- RNA and protein synthesis mechanisms
- Blood properties and coagulation
- Plant Virus Research Studies
- Signaling Pathways in Disease
- RNA modifications and cancer
Children's Hospital of Philadelphia
2014-2024
University of Pennsylvania
2014-2024
Uppsala University
2024
University of San Diego
2024
Pennsylvania Hospital
2024
Philadelphia University
2002-2023
Society for Classical Studies
2020
Weston Solutions (United States)
2013
Institute of Molecular Biology and Biophysics
2013
California University of Pennsylvania
2009
The crystal structure of the binary complex tRNA Asp -aspartyl synthetase from yeast was solved with use multiple isomorphous replacement to 3 angstrom resolution. dimeric synthetase, a member class II aminoacyl synthetases (aaRS's) exhibits characteristic signature motifs conserved in eight aaRS's. These three sequence are contained catalytic site domain, built around an antiparallel β sheet, and flanked by α helices that form pocket which adenosine triphosphate (ATP) CCA end bind. molecule...
The kinetics of the activation human prothrombin catalyzed by prothrombinase was studied using fluorescent alpha-thrombin inhibitor dansylarginine-N-(3-ethyl-1,5-pentanediyl)amide (DAPA). Prothrombinase proteolytically activates to cleavages at Arg273-Thr274 (bond A) and Arg322-Ile323 B). differential fluorescence properties DAPA complexed with intermediates products were exploited study individual bond in zymogen. When catalyst composed (human factor Xa, Va, synthetic phospholipid vesicles,...
Tissue factor (TF) pathway inhibitor (TFPI) regulates X activation through the sequential inhibition of Xa and VIIa·TF complex. Factor formation was studied in a purified, reconstituted system, at plasma concentrations TFPI, saturating VIIa, increasing TF into phosphatidylcholine:phosphatidylserine membranes (TF/PCPS) or PC (TF/PC). The initial rate equivalent presence absence 2.4 nm TFPI. However, reaction extent small (<20%) relative to that observed implying rapid during activation....
The binding to human rhinovirus 14 of a series eight antiviral agents that inhibit picornaviral uncoating after entry into host cells has been characterized crystallographically. All these bind the same hydrophobic pocket within viral protein VP1 beta-barrel structure, although orientation and position each compound was found differ. compounds cause shell be less flexible, thereby inhibiting disassembly. Although potency varies by 120-fold, they all induce conformational changes on virion....
The kinetics of the assembly prothrombinase complex was studied using factor Xa modified with active site-directed fluorophore dansylglutamylglycylarginyl chloromethyl ester (DEGR.Xa) as a reporter for process. Stopped-flow kinetic studies were undertaken at saturating concentrations calcium ion, vesicles composed phosphatidylcholine and phosphatidylserine (PCPS), Va, DEGR.Xa. rate formation, under pseudo first-order conditions, depended on premixing protocol used to initiate most rapid when...
Arg274-Thr275, and the other at Arg323-11e324 (2-5).The peptide comprising residues 1 through 274 has a molecular weight of 34,000 is known as prothrombin fragment 1.2.The remaining two peptides are disulfide-linked, have combined
Coagulation factor X is activated by the extrinsic Xase complex composed of VIIa associated with integral membrane protein tissue factor. The kinetics human activation was studied following reconstitution this reaction system using purified proteins and synthetic phospholipid vesicles phosphatidylcholine phosphatidylserine (PCPS) or alone (PC). Factor evaluated discontinuous measurements amidolytic activity product, Xa, continuously monitored fluorescent serine protease inhibitor...
Equilibrium binding studies of prothrombinase complex formation were undertaken using phospholipid vesicles composed phosphatidylcholine and phosphatidylserine (PCPS), factor Va, Xa modified with dansyl glutamylglycinylarginyl chloromethyl ketone (DEGR.Xa). The interaction between the Va.PCPS DEGR.Xa.PCPS binary complexes was experimentally isolated saturating concentrations PCPS. Fluorescence titrations indicated that membrane-bound proteins interact tightly (Kd approximately 10(-9) M) a...
The analysis of free sulfhydryl groups in factor Va using dithiobis-(nitrobenzoic acid) (DTNB) indicated the presence one accessible thiol each two subunits cofactor. Intact contained readily group under native conditions and approximately such after denaturation. A comparison rate modification to those observed with isolated that present component D cofactor was reaction DTNB. Factor reacted sulfhydryl-directed fluorophore N-(1-pyrene)maleimide, resulting concomitant loss no detectable...
Proteolytic processing of von Willebrand factor (VWF) by ADAMTS13 metalloproteinase is crucial for normal hemostasis. In vitro, cleavage VWF slow even at high shear stress and typically studied in the presence denaturants. We now show that, under physiological pH ionic strength, coagulation VIII (FVIII) accelerates, a approximately 10, rate specific Tyr(1605)-Met(1606) bond VWF. Multimer analysis reveals that FVIII preferentially accelerates high-molecular-weight multimers. This enhancement...
Activated protein C has been derivatized with the active site-directed fluorophore 2-(dimethylamino)-6-naphthalenesulfonylglutamylglycylarginyl chloromethyl ketone (2,6-DEGR-APC). Covalently modified activated used to investigate binding interactions of factors V and Va in presence phospholipid vesicles. The fluorescence polarization 6-dimethylaminonaphthalene-2-sulfonyl moiety increased saturably increasing concentrations or absence factor Va. Differences limiting values indicated...
Glutamylglycinylarginyl chloromethyl ketone, tyrosylglycinylarginyl and phenylalanylprolylarginyl ketone have been labeled at their amino termini using fluorescein, rhodamine-X, lissamine-rhodamine, pyrene, the 1,5-, 2,5-, 2,6-dimethylaminonaphthalene-1-sulfonyl moieties. These peptidyl ketones also modified by incorporation of biotin epsilon-amino caproyl biotin. The ability these various to be incorporated into a collection zymogen-enzyme pairs has evaluated variety coagulation...
Abstract Potent and selective inhibition of the structurally homologous proteases coagulation poses challenges for drug development. Hematophagous organisms frequently accomplish this by fashioning peptide inhibitors combining exosite active site binding motifs. Inspired biological strategy, we create several EXACT targeting thrombin factor Xa de novo linking EXosite-binding aptamers with small molecule ACTive inhibitors. The aptamer component within inhibitor (1) synergizes enhances potency...