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DSF protein

Shotaro Honda, Toshiyuki Kunii, Kenta Nohara, Satoshi Wakita, Yasusato Sugahara, Masao Kawakita, Fumitaka Oyama, Masayoshi Sakaguchi
Bacillus thuringiensis is a Gram-positive soil bacterium that is known to be a bacterial biopesticide that produces insecticidal proteins called crystal proteins (Cry). In the insecticidal process, chitinases are suggested to perforate the peritrophic membrane barrier to facilitate the invasion of the Cry proteins into epithelial membranes. A chitinase gene from B. thuringiensis was successfully expressed in a soluble form in Escherichia coli, and the gene product was purified and characterized. The purified recombinant enzyme, BthChi74, hydrolyzed an artificial substrate, 4-nitrophenyl N,N'-diacetyl-β-D-chitobioside [4NP-(GlcNAc)2], and the natural substrates, colloidal chitin and crystalline α-chitin, but it did not hydrolyze cellulose...
December 2017: AMB Express
Yangcheng Ding, Huajun Feng, Dongsheng Shen, Na Li, Meizhen Wang, Yuyang Zhou
This study investigated the effect of organic shock loads on the stability of anaerobic granular sludge (AnGS). At double and triple shock intensity (8 and 12 kg COD/m(3)d organic loading rate (OLR), respectively), the accumulation of volatile fatty acids resulted in the decreasing pH of the reactors. The unstable performances of AnGS also appeared in the macroscopic properties, including the decreasing contents of relative hydrophobicity (RH), granular strength and diameter, and the fluctuation of EPS production...
February 15, 2017: Environmental Technology
Ranjan Bista, David W Lee, Oliver B Pepper, David O Azorsa, Robert J Arceci, Eiman Aleem
BACKGROUND: Children with Down syndrome (DS) have increased risk for developing AML (DS-AMKL), and they usually experience severe therapy-related toxicities compared to non DS-AMKL. Refractory/relapsed disease has very poor outcome, and patients would benefit from novel, less toxic, therapeutic strategies that overcome resistance. Relapse/resistance are linked to cancer stem cells with high aldehyde dehydrogenase (ALDH) activity. The purpose of the present work was to study less toxic alternative therapeutic agents for relapsed/refractory DS-AMKL...
February 1, 2017: Journal of Experimental & Clinical Cancer Research: CR
Neha Sahni, Rajoshi Chaudhuri, John M Hickey, Prakash Manikwar, Ajit D'Souza, Andrew Metters, Sangeeta B Joshi, C Russell Middaugh, David B Volkin
This study describes the physicochemical characterization, stabilization, and formulation design of SM4-AC, an acrylodan-labeled glucose/galactose-binding protein for use in a continuous glucose monitoring device. The physical stability profile of SM4-AC as a function of pH and temperature was monitored using a combination of biophysical techniques and the resulting physical stability profile was visualized using an empirical phase diagram. Forced degradation chemical stability studies (Asn deamidation, Met oxidation) of SM4-AC were performed using a combination of capillary isoelectric focusing, peptide mapping, and reversed-phase HPLC...
January 11, 2017: Journal of Pharmaceutical Sciences
Thaiesha A Wright, Jamie M Stewart, Richard C Page, Dominik Konkolewicz
Thermodynamic properties of protein unfolding have been extensively studied; however, the methods used have typically required significant preparation time and high protein concentrations. Here we present a facile, simple, and parallelized differential scanning fluorimetry (DSF) method that enables thermodynamic parameters of protein unfolding to be extracted. This method assumes a two-state, reversible protein unfolding mechanism and provides the capacity to quickly analyze the biophysical mechanisms of changes in protein stability and to more thoroughly characterize the effect of mutations, additives, inhibitors, or pH...
January 12, 2017: Journal of Physical Chemistry Letters
Aurangazeb Kabir, Satoshi Endo, Naoki Toyooka, Mayuko Fukuoka, Kazuo Kuwata, Yuji O Kamatari
Inhibitors of AKR1B10 belonging to the aldo-keto reductase (AKR) superfamily are considered promising candidates for anti-cancer drugs. AKR1B1, a structurally similar isoform of AKR1B10, is involved in glucose metabolism. Thus, selective inhibition of AKR1B10 is required for the development of anti-cancer drugs. In this study, we first compared correlations between melting temperature and the 50% inhibition concentration obtained from differential scanning fluorimetry (DSF) and an enzyme inhibitory experiment, respectively, and a good correlation was found, except for compounds with low solubility...
December 21, 2016: Journal of Biochemistry
Jon Ashley, Yunus Shukor, Ibtisam E Tothill
The development of molecularly imprinted polymer nanoparticles (MIP-NPs), which specifically bind biomolecules, is of great interest in the area of biosensors, sample purification, therapeutic agents and biotechnology. Polymerisation techniques such as precipitation polymerisation, solid phase synthesis and core shell surface imprinting have allowed for significant improvements to be made in developing MIP-NPs which specifically recognise proteins. However, the development of MIP-NPs for protein templates (targets) still require lengthy optimisation and characterisation using different ratios of monomers in order to control their size, binding affinity and specificity...
November 14, 2016: Analyst
Jamie A Abbott, Nathan M Livingston, Shawn B Egri, Ethan Guth, Christopher S Francklyn
Differential scanning fluorimetry (DSF) is a fluorescence-based assay to evaluate protein stability by determining protein melting temperatures. Here, we describe the application of DSF to investigate aminoacyl-tRNA synthetase (AARS) stability and interaction with ligands. Employing three bacterial AARS enzymes as model systems, methods are presented here for the use of DSF to measure the apparent temperatures at which AARSs undergo melting transitions, and the effect of AARS substrates and inhibitors. One important observation is that the extent of temperature stability realized by an AARS in response to a particular bound ligand cannot be predicted a priori...
January 15, 2017: Methods: a Companion to Methods in Enzymology
Aida Llauró, Pablo Guerra, Ravi Kant, Brian Bothner, Núria Verdaguer, Pedro J de Pablo
Vault particles are naturally occurring proteinaceous cages with promising application as molecular containers. The use of vaults as functional transporters requires a profound understanding of their structural stability to guarantee the protection and controlled payload delivery. Previous results performed with bulk techniques or at non-physiological conditions have suggested pH as a parameter to control vault dynamics. Here we use Atomic Force Microscopy (AFM) to monitor the structural evolution of individual vault particles while changing the pH in real time...
October 14, 2016: Scientific Reports
Jifeng Zhang, Vadim Frey, Marta Corcoran, Jian Zhang-van Enk, J Anand Subramony
Thermal stability of the CH2 domain for an IgG1 monoclonal antibody and its aggregation kinetics were systematically studied at pH 4.8, below its pI of 8.8 in individual solutions of arginine salts with acetate, glutamate (Glu(-)), chloride, and sulfate as the anion, in comparison to sodium chloride and sodium sulfate. Thermal unfolding temperature, Tm, an indicator of thermal stability, was measured by both differential scanning calorimetry (DSC) and differential scanning fluorimetry (DSF). The aggregation kinetics was determined by assessing reversibility for the CH2 domain in the DSC repetitive scans and then cross-examined by the isothermal aggregation study measured by size exclusion chromatography...
October 3, 2016: Molecular Pharmaceutics
Zhiqiang Chen, Chao Huang, Naresh Chennamsetty, Xuankuo Xu, Zheng Jian Li
Cation-exchange chromatography (CEX) of a structurally unstable Fc-fusion protein exhibited multi-peak elution profile upon a salt-step elution due to protein aggregation during intra-column buffer transition where low pH and high salt coexisted. The protein exhibited a single-peak elution behavior during a pH-step elution; nevertheless, the levels of soluble aggregates (i.e. high molecular weight species, HMW) in the CEX eluate were still found up to 12-fold higher than that for the load material. The amount of the aggregates formed upon the pH-step elution was dependent on column loading with maximum HMW achieved at intermediate loading levels, supporting the hypothesis that the aggregation was the result of both the conformational changes of the bound protein and the solution concentration of the aggregation-susceptible proteins during elution...
August 19, 2016: Journal of Chromatography. A
Dominic P Byrne, Matthias Vonderach, Samantha Ferries, Philip J Brownridge, Claire E Eyers, Patrick A Eyers
cAMP-dependent protein kinase (PKA) is an archetypal biological signaling module and a model for understanding the regulation of protein kinases. In the present study, we combine biochemistry with differential scanning fluorimetry (DSF) and ion mobility-mass spectrometry (IM-MS) to evaluate effects of phosphorylation and structure on the ligand binding, dynamics and stability of components of heteromeric PKA protein complexes in vitro We uncover dynamic, conformationally distinct populations of the PKA catalytic subunit with distinct structural stability and susceptibility to the physiological protein inhibitor PKI...
October 1, 2016: Biochemical Journal
Christoph Giese, Jonathan Eras, Anne Kern, Martin A Schärer, Guido Capitani, Rudi Glockshuber
The complex between the bacterial type 1 pilus subunit FimG and the peptide corresponding to the N-terminal extension (termed donor strand, Ds) of the partner subunit FimF (DsF) shows the strongest reported noncovalent molecular interaction, with a dissociation constant (KD ) of 1.5×10(-20)  m. However, the complex only exhibits a slow association rate of 330 m(-1)  s(-1) that limits technical applications, such as its use in affinity purification. Herein, a structure-based approach was used to design pairs of FimGt (a FimG variant lacking its own N-terminal extension) and DsF variants with enhanced electrostatic surface complementarity...
August 1, 2016: Angewandte Chemie
Umesh Yadava, Matthew W Vetting, Nawar Al Obaidi, Michael S Carter, John A Gerlt, Steven C Almo
The uptake of exogenous solutes by prokaryotes is mediated by transport systems embedded in the plasma membrane. In many cases, a solute-binding protein (SBP) is utilized to bind ligands with high affinity and deliver them to the membrane-bound components responsible for translocation into the cytoplasm. In the present study, Avi_5305, an Agrobacterium vitis SBP belonging to Pfam13407, was screened by differential scanning fluorimetry (DSF) and found to be stabilized by D-glucosamine and D-galactosamine. Avi_5305 is the first protein from Pfam13407 shown to be specific for amino sugars, and co-crystallization resulted in structures of Avi_5305 bound to D-glucosamine and D-galactosamine...
June 2016: Acta Crystallographica. Section F, Structural Biology Communications
Christine L Childers, Stuart R Green, Neal J Dawson, Kenneth B Storey
The effect of protein stability on kinetic function is monitored with many techniques that often require large amounts of expensive substrates and specialized equipment not universally available. We present differential scanning fluorimetry (DSF), a simple high-throughput assay performed in real-time thermocyclers, as a technique for analysis of protein unfolding. Furthermore, we demonstrate a correlation between the half-maximal rate of protein unfolding (Knd), and protein unfolding by urea (I50). This demonstrates that DSF methods can determine the structural stability of an enzyme's active site and can compare the relative structural stability of homologous enzymes with a high degree of sequence similarity...
September 1, 2016: Analytical Biochemistry
Sujit Suklabaidya, Biswajit Das, Syed Azmal Ali, Sumeet Jain, Sharada Swaminathan, Ashok K Mohanty, Susen K Panda, Pujarini Dash, Subhankar Chakraborty, Surinder K Batra, Shantibhusan Senapati
Desmoplasia in human pancreatic cancer (PC) promotes cancer progression and hinders effective drug delivery. The objectives of this study were to characterize a homologous orthotopic model of PC in Syrian golden hamster and investigate the effect of anti-fibrotic (pirfenidone), antioxidant (N-acetyl cysteine, NAC) and anti-addiction (disulfiram, DSF) drugs on desmoplasia and tumor growth in this model. The HapT1 PC cells when implanted orthotopically into hamsters formed tumors with morphological, cellular and molecular similarities to human PC...
July 5, 2016: Oncotarget
Kara A DeSantis, Jeffrey L Reinking
Identification of small molecules that interact specifically with the ligand-binding domains (LBDs) of nuclear receptors (NRs) can be accomplished using a variety of methodologies. Here, we describe the use of differential scanning fluorimetry to identify these ligands, a technique that requires no modification or derivatization of either the protein or the ligand, and uses an instrument that is becoming increasingly affordable and common in modern molecular biology laboratories, the quantitative, or real-time, PCR machine...
2016: Methods in Molecular Biology
Erik Vernet, Gina Popa, Irina Pozdnyakova, Jakob E Rasmussen, Holger Grohganz, Lise Giehm, Malene H Jensen, Huabing Wang, Bitten Plesner, Hanne M Nielsen, Knud J Jensen, Jens Berthelsen, Michael Sundström, Marco van de Weert
PEGylation is the most widely used method to chemically modify protein biopharmaceuticals, but surprisingly limited public data is available on the biophysical effects of protein PEGylation. Here we report the first large-scale study, with site-specific mono-PEGylation of 15 different proteins and characterization of 61 entities in total using a common set of analytical methods. Predictions of molecular size were typically accurate in comparison with actual size determined by size-exclusion chromatography (SEC) or dynamic light scattering (DLS)...
May 2, 2016: Molecular Pharmaceutics
Wantong Song, Zhaohui Tang, Na Shen, Haiyang Yu, Yanjie Jia, Dawei Zhang, Jian Jiang, Chaoliang He, Huayu Tian, Xuesi Chen
A poly(l-glutamic acid) graft polyethylene glycol-cisplatin complex (PGA-CisPt) performs well in reducing the toxicity of free cisplatin and greatly enhances the accumulation and retention of cisplatin in solid tumors. However, there is a lack of effective treatment options for cisplatin-resistant tumors. A major reason for this is the dense PEG shell, which ensures that the PGA-CisPt maintains a long retention time in the blood that may result in it bypassing the tumor cells or failing to be endocytosed within the tumor microenvironment...
June 10, 2016: Journal of Controlled Release: Official Journal of the Controlled Release Society
Katrin Viigand, Triinu Visnapuu, Karin Mardo, Anneli Aasamets, Tiina Alamäe
Saccharomyces cerevisiae maltases use maltose, maltulose, turanose and maltotriose as substrates, isomaltases use isomaltose, α-methylglucoside and palatinose and both use sucrose. These enzymes are hypothesized to have evolved from a promiscuous α-glucosidase ancMALS through duplication and mutation of the genes. We studied substrate specificity of the maltase protein MAL1 from an earlier diverged yeast, Ogataea polymorpha (Op), in the light of this hypothesis. MAL1 has extended substrate specificity and its properties are strikingly similar to those of resurrected ancMALS...
August 2016: Yeast
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