The differential adsorption heats of oxygen and NO, as well as catalytic oxidation behavior during NO oxidation and NO2 dissociation reactions over supported Pt-catalysts, were investigated by microcalorimetric measurements. The average heat of adsorption (Delta H) of oxygen ranged from 310 kJ/mol at 200 degrees C to 289 kJ/mol at 400 degrees C. Over this temperature range formation of platinum oxides and coverage dependence caused variations in the apparent heat of adsorption. NO heat of adsorption from 50 to 150 degrees C was near constant with an average value of 202 kJ/mol over the temperature range.
Polycyclic aromatic hydrocarbons (PAHs) are widespread in various ecosystems and are pollutants of great concern due to their potential toxicity, mutagenecity and carcinogenicity. Surfactant has become a hot topic for its wide application in the bioremediation of PAHs. The aim of this work is to explore a microcalorimetric method to determine the toxic effect of pyrene on Bacillus subtilis (B. subtilis) and the PAH-degrading bacteria Burkholderia cepacia (B. cepacia) and to evaluate the effect of Tween 80 on biodegradation of pyrene. Power-time curves were studied and calorimetric parameters including the growth rate constant (k), half inhibitory concentration (IC50), and total thermal effect (QT) were determined. B. subtilis, B. cepacia and B. cepacia with Tween 80 were completely inhibited when the concentration of pyrene were 200, 800 and 1600μgmL-1, respectively. B. cepacia shows better tolerance to pyrene than B. subtilis. Tween 80 significantly improves the biodegradation of pyrene by increasing
The thermodynamics of a monoclonal antibody (mAb)-peptide interaction have been characterized by isothermal titration microcalorimetry. GCC:B10 mAb, generated against human guanylyl cyclase C, a membrane-associated receptor and a potential marker for metastatic colon cancer, recognizes the cognate peptide epitope HIPPENIFPLE and its two contiguous mimotopes, HIPPEN and ENIFPLE, specifically and reversibly. The exothermic binding reactions between 6.4 and 42 degreeC are driven by dominant favorable enthalpic contributions between 20 and 42 degreeC, with a large negative heat capacity (DELTACp) of -421 +- 27 cal mol-1 K-1. The unfavorable negative value of entropy (DELTASb0) at 25 degreeC, an unusual feature among protein-protein interactions, becomes a positive one below an inversion temperature of 20.5 degreeC. Enthalpy-entropy compensation due to solvent reorganization accounts for an essentially unchanged free energy of interaction (DELTADELTAGb0 simeq 0). The role of water molecules in the ...
Binding of enzymatic E colicins to the vitamin B12 receptor, BtuB, is the first stage in a cascade of events that culminate in the translocation of the cytotoxic nuclease into the Escherichia coli cytoplasm and release of its tightly bound immunity protein. A dogma of colicin biology is that the toxin coiled-coil connecting its functional domains must unfold or unfurl to span the periplasm, with recent reports claiming this reaction is initiated by receptor binding. We report isothermal titration calorimetry data of BtuB binding the endonuclease toxin ColE9 and a disulfide form (ColE9S-S) where unfolding of the coiled-coil is prevented and, as a consequence, the toxin is biologically inactive. Contrary to expectation, the thermodynamics of receptor binding, characterized by large negative values for TDeltaS, are identical for the two colicins, arguing against any form of BtuB-induced unfolding. We go on to delineate key features of the colicin translocon that assembles at the cell surface after BtuB
Cooperative binding pervades Nature. This review discusses the use of isothermal titration calorimetry (ITC) in the identification and characterisation of cooperativity in biological interactions. ITC has broad scope in the analysis of cooperativity as it determines binding stiochiometries, affinities and thermodynamic parameters, including enthalpy and entropy in a single experiment. Examples from the literature are used to demonstrate the applicability of ITC in the characterisation of cooperative systems.
Integral membrane proteins, including G protein-coupled receptors (GPCR) and ion channels, mediate diverse biological functions that are crucial to all aspects of life. The knowledge of the molecular mechanisms, and in particular, the thermodynamic basis of the binding interactions of the extracellular ligands and intracellular effector proteins is essential to understand the workings of these remarkable nanomachines. In this review, we describe how isothermal titration calorimetry (ITC) can be effectively used to gain valuable insights into the thermodynamic signatures (enthalpy, entropy, affinity, and stoichiometry), which would be most useful for drug discovery studies, considering that more than 30% of the current drugs target membrane proteins. This article is part of a Special Issue entitled: Structural and biophysical characterisation of membrane protein-ligand binding.
With their hydrolytic, optical and magnetic properties, lanthanide ions (Ln3+) are versatile probes for nucleic acids. In addition, nucleotide-coordinated Ln3+ ions form useful nanoparticles. However, the thermodynamic basis of their interaction is still lacking. In this work, isothermal titration calorimetry (ITC) is used to study the binding between nucleotides and 14 different Ln3+ ions. Ln3+ interacts mainly with the phosphate of cytidine and thymidine monophosphate (CMP and TMP), while the nucleobases in adenosine and guanosine monophosphate (AMP and GMP) are also involved. Phosphate binding is fully entropy driven since the reactions absorb heat. Nucleosides alone do not bind Ln3+ and the purines need the phosphate for chelation. With increasing atomic number of Ln3+, the binding reaction with GMP goes from exothermic to endothermic. The entropy contribution starts to increase from Gd3+, explaining the gadolinium break observed in many Ln3+-mediated RNA cleavage reactions. This study ...
Isothermal titration calorimetry profiles of Alba1 binding to various DNA.A-DNA (a), and B-DNA (b) and CT-DNA (c), at 25°C in 50 mM NaH2PO4, pH 7.0.
The binding of a series of low molecular weight ligands towards trypsin and thrombin has been studied by isothermal titration calorimetry and protein crystallography. In a series of congeneric ligands, surprising changes of protonation states occur and are overlaid on the binding process. They result from induced pK(a) shifts depending on the local environment experienced by the ligand and protein functional groups in the complex (induced dielectric fit). They involve additional heat effects that must be corrected before any conclusion on the binding enthalpy (DeltaH) and entropy (DeltaS) can be drawn. After correction, trends in both contributions can be interpreted in structural terms with respect to the hydrogen bond inventory or residual ligand motions. For all inhibitors studied, a strong negative heat capacity change (DeltaC(p)) is detected, thus binding becomes more exothermic and entropically less favourable with increasing temperature. Due to a mutual compensation, Gibbs free energy ...
67 matching references were found. Hernandez de la T.; Romero I., Physical interaction between n-alkanes, Rev. Colomb. Quim., 1987, 14, 71. [all data] Helmig, D.; Revermann, T.; Pollmann, J.; Kaltschmidt, O.; Hernández, A.J.; Bocquet, F.; David, D., Calibration system and analytical considerations for quantitative sesquiterpene measurements in air, J. Chromatogr. A, 2003, 1002, 1-2, 193-211, https://doi.org/10.1016/S0021-9673(03)00619-8 . [all data] Damon, A.A.; Hernández, A.S.; Rojas, J.C., Analysis of the fragrance produced by the epiphytic orchid Anathallis (Pleurothallis) racemiflora (orchidaceae) in the Soconusco region, Chiapas, Mexico, Lindleyana, 2002, 17, 2, 93-97. [all data] Paz Andrade, M.I.; Hernandez, C.; Nunez, L.; Jimenez Cuesta, E., Microcalorimetric study of heats of mixing for the systems benzene + o-, m- , and p-xylene at 50c, J. Chim. Phys. Phys.-Chim. Biol., 1972, 69, 1132-5. [all data] Paz-Andrade, M.E.; Jimenez Cuesta, E.; Hernandez, C., Newassembly for microcalorimetric ...
en] A new microcalorimetric method for recording the kinetic parameters k(cat)/K-m and K-i of alpha-amylases using polysaccharides and oligosaccharides as substrates is described. This method is based on the heat released by glycosidic bond hydrolysis. The method has been developed to study the active site properties of the cold-active alpha-amylase produced by an Antarctic psychrophilic bacterium in comparison with its closest structural homolog from pig pancreas. It is shown that the psychrophilic a-amylase is more active on large macromolecular substrates and that the higher rate constants k(cat) are gained at the expense of a lower affinity for the substrate. The active site is able to accommodate larger inhibitory complexes, resulting in a mixed-type inhibition of starch hydrolysis by maltose. A method for recording the binding enthalpies by isothermal titration calorimetry in a low-affinity system has been developed, allowing analysis of the energetics of weak ligand binding using the ...
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In the cement industry, the extrusion technique is used to produce flat shapes with improved resistance to compression. Extrusion is a plastic-forming process that consists of forcing a highly viscous plastic mixture through a shaped die. The material should be fluid enough to be mixed and to pass through the die, and on the other hand, the extruded specimen should be stiff enough to be handled without changing in shape or cracking. These characteristics are industrially obtained by adding cellulosic polymers to the mixture. The aim of this work is to understand the action mechanism of these additives on the major pure phases constituting a typical Portland cement: tricalcium silicate (C3S), dicalcium silicate (C2S), tricalcium aluminate (C(3)A), and tetracalcium iron-aluminate (C(4)AF). In particular, a methylhydroxyethyl cellulose (MHEC) was selected from the best-performing polymers for further study. The effect of this additive on the hydration kinetics (rate constants, activation energies, ...
I am a phD Student in Spain and i´m currently starting to work with ITC. What I want is to stablish Kd between my protein and some inhibitors. Actually I´m having quite a lot of problems because i´m not able to establish the optimal concentrations conditions to see the union. Could you explain me, please, how do you to to stablish which are your optimal conditions to work ...
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Introduction. COMPARING THE ENTHALPY CHANGE OF COMBUSTION OF DIFFERENT ALCHOHOLS. Aim The aim of my experiment will be to find out which alcohols have a higher enthalpy change of combustion. The comparison of the enthalpy changes of these fuels will then determine the alcohol efficiency and effectiveness. I will experiment on the first 5 consecutive primary alcohols. These are; methanol, ethanol, propan-1-ol, butan-1-ol, pentan-1-ol and hexan-1-ol. The reason why I chose these fuels is because they are the most reliable and accurate fuels to compare within the group; which also have the smallest variable, add one carbon each time, to the aliphatic chain. All combustion reactions are exothermic which is why I am expecting all the values for the enthalpy change of combustion to always be negative. CH3OH + 1.5O2 CO2 + 2H2O METHANOL CH3CH 2OH+ 3O2 2CO2 + 3H2O ETHANOL CH3CH 2 CH 2OH+ 4.5O2 3CO2 + 4H2O PROPAN-1-OL CH3CH 2 CH 2 CH 2OH+ 6O2 4CO2 + 5H2O BUTAN-1-OL CH3CH 2 CH 2 CH 2 CH 2OH+ 7.5O2 5CO2 + ...
Chemokines are peptide ligands that activate G protein-coupled receptors and that bind glycosaminoglycans (GAGs) on the cell surface. Through these two interactions, chemokines participate in leukocyte migration and inflammatory signaling. Although studies of crystals and solution structures indicate that chemokines are dimers, various experiments with monomeric interleukin 8 (IL-8) suggest that the monomer may activate its GPCR, CXCR1. Fernando et al. provide in vitro evidence from isothermal titration calorimetry (ITC) and sedimentation equilibrium studies that IL-8 interacts with the N-terminal domain of CXCR1 (site 1) as a monomer. Sedimentation equilibration experiments showed a 1:1 stoichiometry and suggested that the dimeric IL-8 in solution must dissociate to bind the receptor peptide. ITC experiments supported the conclusion that the ligand dimer dissociated and then IL-8 bound to the receptor as a monomer. The authors propose that the dimeric IL-8 serves as a negative regulator for ...
For Ni/CeZrO catalyst prepared in supercritical isopropanol main features of methane dry reforming reaction mechanism were studied by the pulse microcalorimetric technique. The reaction scheme is described by a step-wise redox mechanism with independent stages of CH4 transformation on Ni/support interface producing syngas with participation of support oxygen bridging species (the rate-limiting stage) and fast reoxidation of support sites by CO2 yielding CO regenerating reactive oxygen species.
Abstract: The formation constant (K) and thermodynamic parameters (ΔC.ΔH.ΔS) in reactions in which complexes of adenosine triphosphate with magnesium ion and calcium ion are formed have been obtained by a microcalorimetric method ...
The paper frankly discusses some of the limits of using enthalpy arrays. For example, since the fragment should be present at a higher concentration than enzyme, very tight binders would require unfeasibly low enzyme concentrations. This limits the practical range of the technique to inhibitors with KIs ranging from ~500 nM to 2 mM. Also, as Morgen G observed in a comment to the last post, this is more of a biochemical assay (monitoring the heat of an enzymatic reaction) rather than what most people think of when you say the word calorimetry (monitoring the heat of binding, as in the case of isothermal titration calorimetry). Still, enthalpy arrays seem pretty cool; hopefully folks will warm to them ...
When extremely low temperature calorimetry measurements are not necessary, BT2.15 can be equipped with a high performance chiller adapted to the users temperature range. -10 to 195 °C, -30 to 165 °C and -50 to 115 °C are already available. More can be made available on request.. High pressure cell ...
No binding heat in Substrate and Enzyme ITC - posted in Molecular Biology: Dear all, I did the ITC (isothermal titration calorimetry) between an enzyme with its known substrate on Microcal ITC200. The concentartion of the ligand (substarte) is 1mM; and the concentration of the enzyme is 100 uM; 1.8 ul/injection X 22 injection; However, there is no heat of binding observed in the raw data (isotherms). (dilution of substrate(substrate to buffer control) seems to consume some heat; dilution o...
Microcalorimetry and UV-vis spectroscopy were used to conduct thermodynamic and kinetic investigations of the scission of calf thymus DNA catalyzed by bleomycin A5 (BLM-A5) in the presence of ferrous ion and oxygen. The molar reaction enthalpy for the cleavage, the Michaelis- Menten constant for calf thymus DNA and the turnover number of BLM-A5 were calculated by a novel thermokinetic method for an enzyme-catalyzed reaction to be )577 ± 19 kJÆmol)1, 20.4 ± 3.8 lM and 2.28 ± 0.49 · 10)2 s)1, respectively, at 37.0 °C. This DNA cleavage was a largely exothermic reaction.... ...
Reaction calorimeters uncover potential safety issues and provide process information under using real time heat flow or heat flux calorimetry.
In the new paper, the researchers tried merging compound 1 with another fragment, compound 2, which also binds at two positions within the protein. Several merging strategies were attempted, and although they all stabilized the protein against thermal denaturation and could be characterized crystallographically bound to the protein, most were no better at blocking DNA binding than the original fragments. Compound 5, however, did show enhanced activity, and was the subject of additional SAR. This led to compound 15, which showed low micromolar binding by isothermal titration calorimetry (ITC) and functional activity. (Oddly, compound 1 appeared to bind considerably more tightly by ITC than suggested by its functional activity, perhaps a result of having two binding sites.) The crystal structure of the optimized, merged compound bound to EthR revealed that compound 15 binds as expected (gray), overlaying with one copy each of compound 2 (magenta) and compound 1 (cyan ...
Characterizing the interactions and stability of biomolecules. Microcalorimetry is used to study reactions involving biomolecules, including interactions
Characterizing the interactions and stability of biomolecules. Microcalorimetry is used to study reactions involving biomolecules, including interactions
Ectodomain shedding of glycoprotein (GP) Ibα is thought to mediate the clearance of activated, aged or damaged platelets. A monoclonal antibody, 5G6, has been developed recently to specifically bind to the GPIbα shedding cleavage site and to inhibit its shedding. However, the molecular mechanism underlying antigen recognition and inhibitory specificity is not clear. To elucidate the structural basis for 5G6 binding to GPIbα, we determined the crystal structure of 5G6 Fab fragment in complex with its epitope peptide KL10 (GPIbα residues 461-470, KLRGVLQGHL), to 2.4-Å resolution. Key residues in both 5G6 and KL10 were mutated to validate their effects in antibody binding by using isothermal titration calorimetry. The 5G6 Fab-KL10 peptide complex structure confirmed the direct association of 5G6 with its target GPIbα residues and elucidated the molecular basis underlying its binding specificity and high affinity. The similar binding properties of 5G6 Fab fragment to GPIbα on human platelets ...
The project will start with the design and ordering of CooA (wild type/mutants) and its response element (wild type/mutants) sequences. CooA mutants were reported to have higher affinity for CO. They were included in our order to shorten CO response time if needed. Two promoters, PCOOF and PCOOM, were previously reported as strong and weak promoters of CooA. We will also design several PCOOF promoter mutants (point mutations). These mutants are expected to have changed affinity for CooA. Binding affinity of CooA and mutated promoters will be determined as a part of characterization work package which includes Isothermal Titration Calorimetry (ITC), Electrophoretic Mobility Shift Assay (EMSA) and Intrinsic Tryptophan Fluorescence (ITF). Following this, promoters with different CooA affinities will be coupled and constructs will be prepared for in-vivo cell sensor experiments ...
The project will start with the design and ordering of CooA (wild type/mutants) and its response element (wild type/mutants) sequences. CooA mutants were reported to have higher affinity for CO. They were included in our order to shorten CO response time if needed. Two promoters, PCOOF and PCOOM, were previously reported as strong and weak promoters of CooA. We will also design several PCOOF promoter mutants (point mutations). These mutants are expected to have changed affinity for CooA. Binding affinity of CooA and mutated promoters will be determined as a part of characterization work package which includes Isothermal Titration Calorimetry (ITC), Electrophoretic Mobility Shift Assay (EMSA) and Intrinsic Tryptophan Fluorescence (ITF). Following this, promoters with different CooA affinities will be coupled and constructs will be prepared for in-vivo cell sensor experiments ...
Isothermal titration calorimetry (ITC) characterizes the thermodynamic driving forces of critical molecular interactions and defines molecular stabilities, being an essential tool in the design of effective biomedical and pharmaceutical treatments. This analysis is based on the accurate measurement of the rate of heat absorbed or evolved when the biomolecule of interest interacts specifically or non-specifically with another macromolecule or ligand. ...
Bauer-Brandl, A. (2009). Characterisation of the Ion Exchange Reaction Between Propranolol-H+ or K+ with AmberliteTM IRP 69 Resin by Both, Isothermal Titration Calorimetry and (Flame) Photometric Equilibrium Analysis. Open Drug Delivery Journal, 3, 10-18. http://doi.org/10.2174/1874126600903010010 ...
Microcalorimetry enables detailed investigation of the interactions between and thermodynamics of molecules/biomolecules and is particularly widely used
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Imagine now, though, that you were running an experiment where sometimes there was a large positive deviation and sometimes a large negative one. If you were to look at the sum of the Z-scores in this case, the positive values and the negative values would tend to cancel each other out and you would come out with a rather small and unimpressive "total Z score", even though the large deviations should not be there according to the null hypothesis. We would then have a case with a small mean but a lot of variance (i.e., a lot more extreme variation around the mean than expected). One way to create a single number which might detect this is to sum, not the Z scores themselves, but their squares. Large negatives and large positives would both show up as positive additions so that a lot of variance would show up as an exceptionally large sum of squares. Of course, the sum would always be non-negative, so a positive deviation does not mean that something is there. We need to know the distribution of ...
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The MicroCal PEAQ-ITC is a highly sensitive, low volume isothermal titration calorimeter for the label-free in solution study of biomolecular interactions. It delivers direct measurement of all binding parameters in a single experiment and can analyze weak to high affinity binders, using as little as 10µg sample. Semi-automated maintenance minimizes operator intervention and the system is upgradable to the fully automated MicroCal PEAQ-ITC Automated, making it ideal for laboratories where speed, sensitivity and the ability to accommodate higher workloads in the future are paramount.. ...
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Complexing between soy proteins (SP) and gum arabic (GA) was achieved by mutual titration of soy protein and gum arabic and was characterized using isothermal titration calorimetry (ITC), turbidity, sedimentation and ternary phase boundaries. In the first section, SP were titrated into GA (SP-to-GA titration) under salt-free condition (no added NaCl) at pH 3.0 and pH 5.6, respectively. ITC experiments displayed exothermic processes at both pH status, but the enthalpy changes (ΔH) at pH 3.0 was −0.70 ± 0.02 cal/g as compared to −0.10 ± 0.01 cal/g at pH 5.6. For SP-to-GA titration at pH 3.0, a sudden turbidity increase was observed at the critical SP/GA mass ratio (rφ) of 0.42, which was approximately equal to the charge density ratio of GA and SP (0.36), indicating the charge compensation was achieved at phase separation point. In the second part, GA was titrated into SP (GA-to-SP titration) under salt-free condition at pH 3.0. An immediate turbidity increase was observed when GA was ...
The general belief that chemical structure determines the biological effect of drugs has led to several techniques to establish structure-activity relationships (SAR) that is useful in the development of more active compounds. Predicting toxic effects based on SAR, one can obtain toxicological data with a low cost-benefit ratio. Chlorophenols that represent a class of toxic agents frequently used in industrial processes are not satisfactorily described in the literature in relation to their toxicity. The main objective of this work is to relate the microbial activities of phenol, anisole and their chlorinated derivatives on Chromobacterium violaceum respiration with their physicochemical properties. Anisole and its chlorinated derivatives were used to evaluate the influence of phenol acidity on biological activity. The calculations were carried out at the semi-empirical AM1 and ab initio DFT levels employing the basis sets CEP-31G, CEP-31+Ge CEP-31G** that were parameterized using the ...
Retroviral genome recognition is mediated by the nucleocapsid (NC) domain of the virally encoded Gag polyprotein, which interacts with cognate RNA packaging elements that typically reside within the 5-untranslated region (5-UTR) of the genome. Recent studies suggest that the packaging signal of Bovine Leukemia Virus (BLV), a member of the human T-cell leukemia virus (HTLV)/BLV family and a non-primate animal model for HTLV-induced leukemogenesis, comprises elements that reside within both the 5-UTR and gag open reading frame. The recombinant BLV NC protein has been prepared and purified. Electrophoretic mobility shift and isothermal titration calorimetry studies with RNA fragments corresponding to these proposed packaging elements have been conducted. The gag-derived RNAs did not exhibit significant affinity for NC, suggesting an alternate role in packaging. However, an 83-nucleotide fragment of the 5-UTR that resides just upstream of the gag start codon binds NC stoichiometrically and with ...
In: XXII International Conference on Raman Spectroscopy. American Institute of Physics, Melville, USA, pp. 839-840. ISBN 9780735408180 ISSN 0094-243X (doi:10.1063/1.3482842) Vine, G.J., Chowdhry, B.Z. and Mitchell, J.C. (2005) Antimicrobial properties of surface-active agents by flow calorimetry. Journal of Pharmacy and Pharmacology, 57 (S1). S107-S107. ISSN 0022-3573 (Print), 2042-7158 (Online) (doi:10.1211/002235705778248406) Seidel, J., Pinkrah, V.T., Mitchell, J.C., Chowdhry, B.Z. and Snowden, M.J. (2004) Isothermal titration calorimetric studies of the acid-base properties of poly (N-isopropylacrylamide-co-4-vinylpyridine) cationic polyelectrolyte colloidal microgels. Thermochimica Acta, 414 (1). pp. 47-52. ISSN 0040-6031 (doi:10.1016/j.tca.2003.11.012) Pinkrah, V.T., Snowden, M.J., Mitchell, J.C., Seidel, J., Chowdhry, B.Z. and Fern, G.R. (2003) Physicochemical properties of poly(N-isopropylacrylamide-co-4-vinylpyridine) cationic polyelectrolyte colloidal microgels. Langmuir, 19 (3). pp. ...
A novel method for the determination of the point of micellar saturation has been developed. To exemplify the theory a model system was considered, this being the saturation of two aqueous micellar solvents with dimethyl phthalate ester (DMP). Upon addition of a hydrophobic compound to an aqueous micellar system partitioning will occur. On further addition, the inner hydrophobic regions will eventually be unable to accommodate any more DMP and, at this specific concentration, the micelle is saturated. With a comparatively large enthalpy change upon partitioning the point of saturation can be determined by a corresponding significant reduction in enthalpy change.. ...
TY - JOUR. T1 - Recognition of septanose carbohydrates by concanavalin A. AU - Castro, Steve. AU - Duff, Michael. AU - Snyder, Nicole L.. AU - Morton, Martha D. AU - Kumar, C. V.. AU - Peczuh, Mark W.. PY - 2005/11/7. Y1 - 2005/11/7. N2 - The ability of the jack bean lectin concanavalin A (ConA) to bind seven membered ring (septanose) monosaccharides has been investigated by isothermal titration calorimetry (ITC) and saturation transfer difference (STD) NMR spectroscopy.. AB - The ability of the jack bean lectin concanavalin A (ConA) to bind seven membered ring (septanose) monosaccharides has been investigated by isothermal titration calorimetry (ITC) and saturation transfer difference (STD) NMR spectroscopy.. UR - http://www.scopus.com/inward/record.url?scp=27844440774&partnerID=8YFLogxK. UR - http://www.scopus.com/inward/citedby.url?scp=27844440774&partnerID=8YFLogxK. U2 - 10.1039/b509243d. DO - 10.1039/b509243d. M3 - Article. VL - 3. SP - 3869. EP - 3872. JO - Organic and Biomolecular ...
Research Interests: Statistical genetics, data modeling and analysis Research experiences Undergraduate thesis: Study on epigenetical regulator CDYL - Feb 2017 - Jun 2017 Supervisor: Haitao LI, professor at Medical School, Tsinghua University - Cloned and got 8 CDYL point mutants, used isothermal titration to test their binding ability to the ligand Acetyl-CoA. Try to confirm the location of catalytic pocket in the amino acid sequence. - Purified and crystalized the CDYL-Acetyl-CoA compound and used x-ray to get structure information. Enrichment of low-abundance genes by engineered ttAgo - Aug 2015 - Dec 2016 Research student (RA), Supervisor: Haitao LI, professor at Medical School, Tsinghua University - Took charge of the TtAgo experiment, modified the purification of TtAgo; succeeded increasing enriching efficiency of low-abundance long noncoding RNA. - Proved the interaction effectiveness of ttAgo-gDNA-mRNA using negative gel electrophoresis and QPCR. - Summarized the process and results
0056]The system described with reference to FIG. 1 may be generalized to n display screens, as shown in FIG. 4. In this figure, the display system comprises n display screens 10 (where n is an integer number more than 2), each screen being controlled by a corresponding display unit 3. The correction system according to the invention comprises a calorimetric measurement and correction system using the separation line 12 between two adjacent screens. Each rank i measurement and correction system (where i is an integer number between 1 and n-1) includes a sensor 7 positioned facing a separation line 12 between two adjacent screens 10 with ranks i and i+1, this sensor being coupled to a calculation device 5 calculating the rank i calorimetric drift, which is connected to a rank i correction device 6, inserted in the control video system of the rank i+1 display unit 3. Therefore this system includes n-1 calorimetric measurement and correction systems, the rank 2 to n display units 3 being adjusted ...
31 P-NMR and Differential Scanning Calorimetry Studies for Determining Vesicleâ s Drug Physical State and Fraction in Alendronate Liposomes Abstract.
Yes, if youre talking about the simple calorimeters that are used in high school labs, which basically consist of thermometers suspended in a container filled with water. The difference between these calorimeters and bomb calorimeters is that simple calorimeters maintain a constant pressure (since its not completely enclosed, and gases can enter and exit the container), while bomb calorimeters maintain a constant volume (sealed so gases cannot flow between the system and the surroundings ...
CheY, the 129 amino acid chemotactic protein from Escherichia coli, is a good model for studies of folding of parallel alpha/beta proteins. We report here the thermodynamic characterization of the wild-type CheY at different pH values and in different buffers and denaturation conditions. The denaturation of CheY by urea monitored by circular dichroism and fluorescence fits the two-state unfolding model. The stability of the protein is ionic strength dependent, probably due to the presence of three Asp residues in very close proximity in its active site. The presence of a Mg2+ ion, which seems to interact with Asp 13 in the active site, stabilizes the native structure by up to 6.9 kJ mol-1. The CheY maximum stability (31.7 +/- 2.1 kJ mol-1), without magnesium, is reached at pH 5.1. Analysis of scanning calorimetry data has shown that temperature-induced unfolding of CheY is not a two-state process and proceeds through a highly populated intermediate state, corresponding to protein dimers, as was ...
The effect of copper(II) ions (Cu+2) on the structure of β-lactoglobulin (β-lg) was investigated spectroscopically using UV-visible, fluorescence and circular dichroism (CD) and calorimetrically using isothermal titration calorimetry (ITC), at different temperatures. Results of the UV-visible studies showed that adding Cu+2 to β-lg solution caused increasing turbidity, indicative of protein aggregation. It was noticeable that the rate of increasing turbidity was directly proportional to increasing temperature. The far-UV CD studies displayed that the Cu+2 cannot induce any significant changes in the secondary structures of β-lg at different temperatures. Also, the ITC data indicated that the binding process of Cu+2 to β-lg is mainly entropically driven. The results highlight that copper ions cause the tertiary structure of β-lg to change and induce a slightly open structure leading to the formation of supramolecular aggregates in β-lg which may result in the reduced allergenicity of β-lg ...