pH- and chaotropic anion-induced conformational changes of tertiary amine-containing binary heterografted star molecular bottlebrushes in aqueous solution

2021 ◽  
Author(s):  
Ethan W. Kent ◽  
Evan M. Lewoczko ◽  
Bin Zhao
Keyword(s):  
Aqueous Solution ◽  
Conformational Changes ◽  
Tertiary Amine ◽  
Ph Changes ◽  
Chaotropic Anions ◽  
Shape Transitions

Three-arm star-shaped, tertiary-amine-containing bottlebrushes exhibit star-globule shape transitions in response to pH changes and addition of sufficiently strong chaotropic anions.

scholarly journals Conformational Changes in Wheat Gluten After using Ag-nanoparticles

2014 ◽  
Vol 28 (3) ◽  
pp. 311-317 ◽  
Author(s):  
Agnieszka Nawrocka
Keyword(s):  
Aqueous Solution ◽  
Silver Nanoparticles ◽  
Secondary Structure ◽  
Conformational Changes ◽  
Fungal Infections ◽  
Wheat Gluten ◽  
Control Sample ◽  
Antimicrobial Properties ◽  
Protective Layer ◽  
Trisodium Citrate

Abstract Silver nanoparticles have antimicrobial properties since they can be regarded as an efficient protector against pathogenic microorganisms. Fourier transform infrared spectroscopy was used to examine conformational changes in the secondary structure of wheat gluten washed out from grain treated with an aqueous solution of silver nanoparticles stabilized by tri-sodium citrate. Silver nanoparticles were used as a protective layer on the grain surface against bacterial and fungal infections (antimicrobial agent). Analysis of the amide I band revealed significant changes in the secondary structure after using silver nanoparticles. An increase in the β-sheet content (from 36.2 to 39.2%) was observed at the expense of the α-helix and β-turn content. To find factors causing these changes, the wheat grains were treated by an aqueous solution of trisodium citrate and water. The results obtained indicate that the changes in the gluten structure were connected mainly with the trisodium citrate action due to presence of a small number of free molecules of the stabilizer in the solution of silver nanoparticles. Additionally, the conformational changes in gluten pointed out that gluten flexibility increased (decrease in the αH/βS ratio from 1.40 for the control sample to 1.26 for the silver nanoparticle-treated samples) as well as the solubility of gluten decreased (decrease in the β-turn content from 13.1 to 11.4%).

pH-Regulated surface property and pH-reversible micelle transition of a tertiary amine-based gemini surfactant in aqueous solution

Soft Matter ◽  
2015 ◽  
Vol 11 (47) ◽  
pp. 9135-9143 ◽  
Author(s):  
Hongsheng Lu ◽  
Miao Xue ◽  
Baogang Wang ◽  
Zhiyu Huang
Keyword(s):  
Aqueous Solution ◽  
Tertiary Amine ◽  
Surface Property ◽  
Gemini Surfactant

Conformational changes of proteins in aqueous solution induced by temperature in the pre-melting region

2001 ◽  
Vol 3 (17) ◽  
pp. 3811-3813 ◽  
Author(s):  
A. Bonincontro ◽  
E. Bultrini ◽  
V. Calandrini ◽  
G. Onori
Keyword(s):  
Aqueous Solution ◽  
Conformational Changes ◽  
Melting Region

scholarly journals CO2 Capture by Absorption in Activated Aqueous Solutions of N,N-Diethylethanoloamine

2017 ◽  
Vol 24 (2) ◽  
pp. 239-248 ◽  
Author(s):  
Ewelina Kruszczak ◽  
Hanna Kierzkowska-Pawlak
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Co2 Capture ◽  
Tertiary Amine ◽  
Absorption Rate ◽  
Absorption Process ◽  
Promising Technique ◽  
Gas Streams ◽  
Hindered Amines ◽  
Amine Solutions

Abstract The CO2 absorption process using aqueous amine solutions has been the most promising technique used for the removal of CO2 from gas streams in energy sector. In recent years, many researchers tested solutions which are composed of several compounds: a slow reacting tertiary amine- and a fast amine acting as an activator. In this paper, the CO2 absorption rate in an aqueous solution of N,N-diethylethanoloamine (DEEA) and activated solutions DEEA is investigated experimentally. The activators considered are sterically hindered amines: 2-amino-2-methyl-1-propanol (AMP), 2-amino-2-methyl-1,3-propanediol (AMPD) and N-methyl-1,3-propanediamine (MAPA) from the group of polyamines. The experiments were conducted over the temperature range of 303-333 K and the total amine concentration of 2 M. From the CO2 absorption experiments into mixed aqueous solutions of DEEA and MAPA, it was found that the addition of small amounts of MAPA into aqueous DEEA solutions has a significant effect on the enhancement of the CO2 absorption rate. The application of hindered amines: AMP or AMP as activators resulted in a marginally improvement of the absorption rate of CO2.

scholarly journals Thermally induced conformational changes and protein–protein interactions of bovine serum albumin in aqueous solution under different pH and ionic strengths as revealed by SAXS measurements

2017 ◽  
Vol 19 (26) ◽  
pp. 17143-17155 ◽  
Author(s):  
Dmitry Molodenskiy ◽  
Evgeny Shirshin ◽  
Tatiana Tikhonova ◽  
Andrey Gruzinov ◽  
Georgy Peters ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Conformational Changes ◽  
Interaction Potential ◽  
Protein Interactions ◽  
Bovine Serum ◽  
Protein Protein Interactions ◽  
Thermally Induced ◽  
Before And After

Temperature-induced oligomerization of albumin before and after protein melting was studied using SAXS and interpreted in terms of interaction potential.

Measurements of Nonlinear Electrical Impedances by Virtue of Induced Conformational Changes in DNAs

2010 ◽  
Vol 22 (5) ◽  
pp. 601-607 ◽  
Author(s):  
Takatoki Yamamoto ◽  
◽  
Sangwook Lee ◽  
Teruo Fujii ◽  
Keyword(s):  
Aqueous Solution ◽  
Conformational Changes ◽  
Electrical Impedance ◽  
Dna Analysis ◽  
Electrical Impedance Spectroscopy ◽  
Label Free ◽  
Impedance Sensing ◽  
Fully Integrated ◽  
Impedance Response ◽  
Strength Dependence

A method for label-free electrical impedance sensing of DNA is proposed, and experimentally demonstrated using a micro Electrical Impedance Spectroscopy (µ- EIS) device. The method features not only the detection of DNA without any labelling, but also the control of the conformation that would enhance the electrical impedance signal. In order to conduct semiautomated measurements controlled by an external PC, a microfluidic chip made of a silicone elastomer of polydimethylsiloxane (PDMS), a measurement chip embedded with micro-electrodes, and a micropump chip are fully integrated in the µ-EIS device. The µ-EIS device is capable of detecting DNA concentrations of a few nM in aqueous solution of a few pL in volume by virtue of the conformation-enhanced nonlinear impedance response. As a first demonstration of conformational-change-induced DNA analysis, the frequency and the electric field strength dependence of various lengths of DNA are evaluated.

THE DISSOCIATION OF α- AND β-LIPOVITELLIN IN AQUEOUS SOLUTION: PART II. INFLUENCE OF PROTEIN PHOSPHATE GROUPS, SULPHYDRYL GROUPS, AND RELATED FACTORS

1962 ◽  
Vol 40 (3) ◽  
pp. 373-379 ◽  
Author(s):  
R. W. Burley ◽  
W. H. Cook
Keyword(s):  
Aqueous Solution ◽  
Complex Formation ◽  
Calcium Ions ◽  
Chromatographic Behavior ◽  
Related Factors ◽  
Sulphydryl Group ◽  
Ph Changes ◽  
Ph Values ◽  
Sulphydryl Groups ◽  
Phosphate Groups

Removal of protein phosphate groups from α- and β-lipovitellin by means of a phosphatase has shown that these groups do not take part in the dissociation–association process. They appear, however, to be responsible for a difference in their ease of complex formation with calcium ions, and also for their different chromatographic behavior on columns of hydroxyapatite.Both lipovitellins contain about 26 μmoles/g of sulphydryl groups. Sulphydryl group reagents had no effect on the dissociation of α-lipovitellin but markedly changed the behavior of β-lipovitellin. N-Ethylmaleimide and p-chloromercuribenzoate displaced the equilibrium towards the associated form at all pH values below pH 10, but iodoacetamide tended to stabilize the dissociated form against pH changes. The different behavior of these reagents indicates that the sulphydryl groups are not directly involved in the dissociation but their substitution probably causes other changes in β-lipovitellin that affect its dissociation.

scholarly journals Microwave Assisted Sol-Gel Synthesis of Silica-Spider Silk Composites

Molecules ◽  
2019 ◽  
Vol 24 (14) ◽  
pp. 2521
Author(s):  
Abul Bashar Mohammad Giasuddin ◽  
David W. Britt
Keyword(s):  
Aqueous Solution ◽  
Infrared Spectroscopy ◽  
Conformational Changes ◽  
Protein Interactions ◽  
Spider Silk ◽  
Sol Gel ◽  
Silk Protein ◽  
Acidic Aqueous Solution ◽  
Silica Nanocomposites ◽  
Spider Silk Protein

This study introduces a simple and environmentally friendly method to synthesize silica-protein nanocomposite materials using microwave energy to solubilize hydrophobic protein in an aqueous solution of pre-hydrolyzed organo- or fluoro-silane. Sol-gel functionality can be enhanced through biomacromolecule incorporation to tune mechanical properties, surface energy, and biocompatibility. Here, synthetic spider silk protein and organo- and fluoro-silane precursors were dissolved and mixed in weakly acidic aqueous solution using microwave technology. Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) images revealed the formation of spherical nanoparticles with sizes ranging from 100 to 500 nm depending, in part, on silane fluoro- or organo-side chain chemistry. The silane-protein interaction in the nanocomposite was assessed through infrared spectroscopy. Deconvoluted ATR-FTIR (Attenuated total reflectance Fourier-transform infrared spectroscopy) spectra revealed silane chemistry-specific conformational changes in the protein-silane nanocomposites. Relative to microwave-solubilized spider silk protein, the β structure content increased by 14% in the spider silk-organo-silica nanocomposites, but decreased by a net 20% in the spider silk-fluoro-silica nanocomposites. Methods of tuning the secondary structures, and in particular β-sheets that are the cross-linking moieties in spider silks and other self-assembling fibrillar proteins, may provide a unique means to promote protein interactions, favor subsequent epitaxial growth process, and enhance the properties of the protein-silane nanocomposites.

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