Search results for: Native Bovine Aprotinin
#27685427 2016/09/29 Save this To Up
Amorphous protein aggregation monitored using fluorescence self-quenching.Biophysical understanding of amorphous protein aggregation can significantly impact diverse area of biotechnology. Here, we report the time dependent salt-induced formation of amorphous aggregation as monitored by fluorescence self-quenching and compare the results with conventional methods for detecting protein aggregation [static light scattering (LS) and dynamic light scattering (DLS)]. As a model protein, we used a bovine pancreatic trypsin inhibitor (BPTI) variant extended by two glycines (C2G) at its C terminus, and three variants where three types of Solubility Controlling Peptide tags (SCP tags) made of five serines (C5S), alanines (C5A) or aspartic acids (C5D) were added to the C terminus of C2G. All variants have a native-like BPTI structure and trypsin inhibitory activity, but different solubilities controlled by the SCP tags. The BPTIs were labeled using NHS-Fluorescein (FAM) conjugated to BPTI's lysines, and we measured the changes in fluorescence intensity occurring upon the addition of NaCl. The fluorescence of all FAM-BPTIs decreased almost immediately, albeit to a different extent, upon addition of salt and became constant after 10 min for 24 h or more. On the other hand, LS and DLS signal changes were dependent on the type of tags. Namely, C2G's LS and DLS signals changed immediately, the signals of C5S and C5A tagged FAM-BPTIs increased slowly from 10 min to 24 h, and those of C5D remained constant. These observations indicated the presence of at least one intermediate step, with increased protein-protein interaction yielding a 'molecular condensation' phase. According to this model, C2G would rapidly turn from 'condensates' to aggregates, whereas C5S and C5A tagged FAM-BPTIs would do so slowly, and the soluble C5D tagged variant would remain in the molecular condensation state.
1403 related Products with: Amorphous protein aggregation monitored using fluorescence self-quenching.Amplite™ Fluorimetric F Green Fluorescence Protei mCherry Fluorescence Prot mCherry Fluorescence Prot Blue Fluorescence Protein Blue Fluorescence Protein Sulforhodamine 101 cadave Myelin Basic Protein Heat Shock Protein 70 (H Heat Shock Protein 70 (H nm23 (NDPK-A Protein); C nm23 (NDPK-A Protein); C
#27523780 2016/09/27 Save this To Up
Structural and functional characterization of complex formation between two Kunitz-type serine protease inhibitors from Russell's Viper venom.Snake venom Kunitz-type serine protease inhibitors (KSPIs) exhibit various biological functions including anticoagulant activity. This study elucidates the occurrence and subunit stoichiometry of a putative complex formed between two KSPIs (Rusvikunin and Rusvikunin-II) purified from the native Rusvikunin complex of Pakistan Russell's Viper (Daboia russelii russelii) venom (RVV). The protein components of the Rusvikunin complex were identified by LC-MS/MS analysis. The non-covalent interaction between two major components of the complex (Rusvikunin and Rusvikunin-II) at 1:2 stoichiometric ratio to form a stable complex was demonstrated by biophysical techniques such as spectrofluorometric, classical gel-filtration, equilibrium gel-filtration, circular dichroism (CD), dynamic light scattering (DLS), RP-HPLC and SDS-PAGE analyses. CD measurement showed that interaction between Rusvikunin and Rusvikunin-II did not change their overall secondary structure; however, the protein complex exhibited enhanced hydrodynamic diameter and anticoagulant activity as compared to the individual components of the complex. This study may lay the foundation for understanding the basis of protein complexes in snake venoms and their role in pathophysiology of snakebite.
1544 related Products with: Structural and functional characterization of complex formation between two Kunitz-type serine protease inhibitors from Russell's Viper venom.Rat Visceral adipose spec Pig thrombin-antithrombin Bovine Androstenedione,AS Homo sapiens,Human,Implan Ecotin (E. coli serine pr Ecotin E. coli serine pro Hamster AntiSerine Protea Hamster AntiSerine Protea MOUSE ANTI APAAP COMPLEX, to FAPβ (Fibroblast Act to FAPβ (Fibroblast Act Protease free heat shock
#27241372 2016/05/31 Save this To Up
Miniature bovine pancreatic trypsin inhibitors (m-BPTIs) of the West Nile virus NS2B-NS3 protease.The mosquito-borne West Nile virus (WNV) causes a wide range of symptoms ranging from fever to the often fatal viral encephalitis. To date, no vaccine or drug therapy is available. The trypsin-like WNV NS2B-NS3 protease is deemed a plausible drug target and was shown to be inhibited by bovine pancreatic trypsin inhibitor (BPTI), a 58-residue protein isolated from bovine lung. Herein, we report a protein truncation study that resulted in a novel 14-residue cyclic peptide with equipotent inhibitory activity to native BPTI. We believe our truncation strategy can be further applied in the development of peptide-based inhibitors targeting trypsin-like proteases.
2541 related Products with: Miniature bovine pancreatic trypsin inhibitors (m-BPTIs) of the West Nile virus NS2B-NS3 protease.West Nile Virus Envelope West Nile Virus Pre M rec Bovine Serum Albumin (BSA West Nile virus Real Time West Nile virus Real Time West Nile virus Real Time West Nile Virus E Prot. R West Nile Virus (Pre-M), Viral antibodies, anti-R anti Rotavirus p42 IgG2a Recombinant Tick-Borne En Recombinant Tick-Borne En
#26866996 2016/03/08 Save this To Up
Demonstrating an Order-of-Magnitude Sampling Enhancement in Molecular Dynamics Simulations of Complex Protein Systems.Molecular dynamics (MD) simulations can describe protein motions in atomic detail, but transitions between protein conformational states sometimes take place on time scales that are infeasible or very expensive to reach by direct simulation. Enhanced sampling methods, the aim of which is to increase the sampling efficiency of MD simulations, have thus been extensively employed. The effectiveness of such methods when applied to complex biological systems like proteins, however, has been difficult to establish because even enhanced sampling simulations of such systems do not typically reach time scales at which convergence is extensive enough to reliably quantify sampling efficiency. Here, we obtain sufficiently converged simulations of three proteins to evaluate the performance of simulated tempering, a member of a widely used class of enhanced sampling methods that use elevated temperature to accelerate sampling. Simulated tempering simulations with individual lengths of up to 100 μs were compared to (previously published) conventional MD simulations with individual lengths of up to 1 ms. With two proteins, BPTI and ubiquitin, we evaluated the efficiency of sampling of conformational states near the native state, and for the third, the villin headpiece, we examined the rate of folding and unfolding. Our comparisons demonstrate that simulated tempering can consistently achieve a substantial sampling speedup of an order of magnitude or more relative to conventional MD.
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#26780557 2016/01/28 Save this To Up
Telomeric G-quadruplex-forming DNA fragments induce TLR9-mediated and LL-37-regulated invasion in breast cancer cells in vitro.Toll-like receptor 9 (TLR9) is a cellular DNA-receptor widely expressed in cancers. We previously showed that synthetic and self-derived DNA fragments induce TLR9-mediated breast cancer cell invasion in vitro. We investigated here the invasive effects of two nuclease-resistant DNA fragments, a 9-mer hairpin, and a G-quadruplex DNA based on the human telomere sequence, both having native phosphodiester backbone. Cellular uptake of DNAs was investigated with immunofluorescence, invasion was studied with Matrigel-assays, and mRNA and protein expression were studied with qPCR and Western blotting and protease activity with zymograms. TLR9 expression was suppressed through siRNA. Although both DNAs induced TLR9-mediated changes in pro-invasive mRNA expression, only the telomeric G-quadruplex DNA significantly increased cellular invasion. This was inhibited with GM6001 and aprotinin, suggesting MMP- and serine protease mediation. Furthermore, complexing with LL-37, a cathelicidin-peptide present in breast cancers, increased 9-mer hairpin and G-quadruplex DNA uptake into the cancer cells. However, DNA/LL-37 complexes decreased invasion, as compared with DNA-treatment alone. Invasion studies were conducted also with DNA fragments isolated from neoadjuvant chemotherapy-treated breast tumors. Also such DNA induced breast cancer cell invasion in vitro. As with the synthetic DNAs, this invasive effect was reduced by complexing the neoadjuvant tumor-derived DNAs with LL-37. We conclude that 9-mer hairpin and G-quadruplex DNA fragments are nuclease-resistant DNA structures that can act as invasion-inducing TLR9 ligands. Their cellular uptake and the invasive effects are regulated via LL-37. Although such structures may be present in chemotherapy-treated tumors, the clinical significance of this finding requires further studying.
2275 related Products with: Telomeric G-quadruplex-forming DNA fragments induce TLR9-mediated and LL-37-regulated invasion in breast cancer cells in vitro.Cultrex In Vitro Angiogen Breast cancer tissue arra Breast cancer (IDC) tissu Breast cancer and adjacen Breast cancer tissue arra Breast cancer tissue arra Breast cancer tissue arra Breast cancer and matched Breast cancer and matched Tissue microarray of brea Breast cancer and matched Breast cancer tissue arra
#26765584 2016/02/09 Save this To Up
Convergence of Molecular Dynamics Simulation of Protein Native States: Feasibility vs Self-Consistency Dilemma.All-atom molecular dynamics simulations need convergence tests to evaluate the quality of data. The notion of "true" convergence is elusive, and one can only hope to satisfy self-consistency checks (SCC). There are multiple SCC criteria, and their assessment of all-atom simulations of the native state for real globular proteins is sparse. Here, we present a systematic study of different SCC algorithms, both in terms of their ability to detect the lack of self-consistency and their computational demand, for the all-atom native state simulations of four globular proteins (CSP, CheA, CheW, and BPTI). Somewhat surprisingly, we notice some of the most stringent SCC criteria, e.g., the criteria demanding similarity of the cluster probability distribution between the first and the second halves of the trajectory or the comparison of fluctuations between different blocks using covariance overlap measure, can require tens of microseconds of simulation even for proteins with less than 100 amino acids. We notice such long simulation times can sometimes be associated with traps, but these traps cannot be detected by some of the common SCC methods. We suggest an additional, and simple, SCC algorithm to quickly detect such traps by monitoring the constancy of the cluster entropy (CCE). CCE is a necessary but not sufficient criteria, and additional SCC algorithms must be combined with it. Furthermore, as seen in the explicit solvent simulation of 1 ms long trajectory of BPTI,1 passing self-consistency checks at an earlier stage may be misleading due to conformational changes taking place later in the simulation, resulting in different, but segregated regions of SCC. Although there is a hierarchy of complex SCC algorithms, caution must be exercised in their application with the knowledge of their limitations and computational expense.
1656 related Products with: Convergence of Molecular Dynamics Simulation of Protein Native States: Feasibility vs Self-Consistency Dilemma.Native Human AMBP Protein Native Human AMBP Protein Native Human A2M Proteins Native Human A2M Proteins Native Human A2M Proteins Native Human SERPINA3 Pro Native Human SERPINA3 Pro Native Human SERPINA3 Pro Native Human AFP Proteins Native Human AFP Proteins Native Human AFP Proteins Native Bovine ALPI CIAP P
#26729044 2016/02/02 Save this To Up
Online Hydrophobic Interaction Chromatography-Mass Spectrometry for Top-Down Proteomics.Recent progress in top-down proteomics has led to a demand for mass spectrometry (MS)-compatible chromatography techniques to separate intact proteins using volatile mobile phases. Conventional hydrophobic interaction chromatography (HIC) provides high-resolution separation of proteins under nondenaturing conditions but requires high concentrations of nonvolatile salts. Herein, we introduce a series of more-hydrophobic HIC materials that can retain proteins using MS-compatible concentrations of ammonium acetate. The new HIC materials appear to function as a hybrid form of conventional HIC and reverse phase chromatography. The function of the salt seems to be preserving protein structure rather than promoting retention. Online HIC-MS is feasible for both qualitative and quantitative analysis. This is demonstrated with standard proteins and a complex cell lysate. The mass spectra of proteins from the online HIC-MS exhibit low charge-state distributions, consistent with those commonly observed in native MS. Furthermore, HIC-MS can chromatographically separate proteoforms differing by minor modifications. Hence, this new HIC-MS combination is promising for top-down proteomics.
2309 related Products with: Online Hydrophobic Interaction Chromatography-Mass Spectrometry for Top-Down Proteomics.Cellufine Formyl , 50 ml Cellufine Formyl Media Cellufine Formyl , 500 ml Cellufine Formyl Media Cellufine Formyl Media Fontana-Masson Stain Kit Fontana-Masson Stain Kit Formalin Solution (20%) Formalin Solution (20%) Formalin Solution (20%) Formalin (10% Neutral Bu Formalin (10% Neutral Bu
#26574336 2015/11/17 Save this To Up
Weighted Distance Functions Improve Analysis of High-Dimensional Data: Application to Molecular Dynamics Simulations.Data mining techniques depend strongly on how the data are represented and how distance between samples is measured. High-dimensional data often contain a large number of irrelevant dimensions (features) for a given query. These features act as noise and obfuscate relevant information. Unsupervised approaches to mine such data require distance measures that can account for feature relevance. Molecular dynamics simulations produce high-dimensional data sets describing molecules observed in time. Here, we propose to globally or locally weight simulation features based on effective rates. This emphasizes, in a data-driven manner, slow degrees of freedom that often report on the metastable states sampled by the molecular system. We couple this idea to several unsupervised learning protocols. Our approach unmasks slow side chain dynamics within the native state of a miniprotein and reveals additional metastable conformations of a protein. The approach can be combined with most algorithms for clustering or dimensionality reduction.
1569 related Products with: Weighted Distance Functions Improve Analysis of High-Dimensional Data: Application to Molecular Dynamics Simulations.Cytokeratin, High Molecu Cytokeratin, High Molecu Cytokeratin, High Molecu Cytokeratin, High Molecu Cytokeratin, High Molecu Cytokeratin, High Molecu TOM1-like protein 2 antib TOK-1 alpha antibody Sour TOM1L1 antibody Source Ra Analysis Tool for AAM-BLG Analysis Tool for AAM-BLM Analysis Tool for AAM-ISO
#26497856 2016/03/31 Save this To Up
Immobilization of enzymes using non-ionic colloidal liquid aphrons (CLAs): Activity kinetics, conformation, and energetics.This study seeks to examine the ability of non-ionic/non-polar Colloidial Liquid Aphrons (CLAs) to preserve enzyme functionality upon immobilization and release. CLAs consisting of micron-sized oil droplets surrounded by a thin aqueous layer stabilized by a mixture of surfactants, were formulated by direct addition (pre-manufacture addition) using 1% Tween 80/mineral oil and 1% Tween 20 and the enzymes lipase, aprotinin and α-chymotrypsin. The results of activity assays for both lipase and α-chymotrypsin showed that kinetic activity increased upon immobilization by factors of 7 and 5.5, respectively, while aprotinin retained approximately 85% of its native activity. The conformation of the enzymes released through desorption showed no significant alterations compared to their native state. Changes in pH and temperature showed that optimum conditions did not change after immobilization, while analysis of activation energy for the immobilized enzyme showed an increase in activity at higher temperatures. Furthermore, the effect of bound water within the aphron structure allowed for some degree of enzyme hydration, and this hydration was needed for an active conformation with results showing a decrease in ΔH* for the immobilized system compared to its native counterpart.
2234 related Products with: Immobilization of enzymes using non-ionic colloidal liquid aphrons (CLAs): Activity kinetics, conformation, and energetics.Rapid Microplate Assay K Colloidal Iron Stain Kit Colloidal Iron Stain Kit Colloidal Iron Stock Sol Colloidal Iron Stock Sol Colloidal Iron Stock Sol human G CSF 75 µg Liquid RPMI 1640 without L Gln, RPMI 1640 without L‐Gln Caspase-3 Substrate DEVD- Caspase-3 Substrate DEVD- Caspase-3 Substrate DEVD-
#26341789 2016/03/19 Save this To Up
Applications of pressure perturbation calorimetry to study factors contributing to the volume changes upon protein unfolding.Pressure perturbation calorimetry (PPC) is a biophysical method that allows direct determination of the volume changes upon conformational transitions in macromolecules.
1521 related Products with: Applications of pressure perturbation calorimetry to study factors contributing to the volume changes upon protein unfolding.TOM1-like protein 2 antib Recombinant Human IFN-alp Recombinant Human IFN-alp Native Influenza HA (A To Native Influenza HA (A To Native Influenza HA (A To Recombinant Human TOP1 Pr Recombinant Human TOP1 Pr Recombinant Human TOP1 Pr Total Protein, 4 x 120 ml FDA Standard Frozen Tissu FDA Standard Frozen Tissu
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