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Protein denaturation

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https://www.readbyqxmd.com/read/28453980/effect-of-ultimate-ph-and-ageing-on-thermal-denaturation-of-bovine-muscle-proteins
#1
Juan D Rios-Mera, Jair Sebastião da Silva Pinto, Carmen J Contreras-Castillo
The thermal denaturation of proteins was evaluated in the natural state of bovine muscle using differential scanning calorimetry (DSC). The Longissimus lumborum muscle was selected according to ultimate pH (pHu) values classified into two groups: low pHu with values between 5.4 and 5.8, and intermediate pHu with values between 5.81 and 6.19. The muscles were cut and aged at 2°C up to 21d post mortem. The three maximum temperatures of denaturation (Tmax1, Tmax2, Tmax3) found in muscle were evaluated, showing higher thermal stability in the intermediate pHu group, which could be an indicator of protection of proteins against aggregation or enzymatic activity...
April 20, 2017: Meat Science
https://www.readbyqxmd.com/read/28448574/fusion-expression-of-occludin-extracellular-loops-and-an-%C3%AE-helical-bundle-a-new-research-model-for-tight-junction
#2
Xiaojing Chi, Xia Zhao, Wei Wang, Yuqiang Niu, Min Cheng, Xiuying Liu, Sheng Cui, Wei Yang
Tight junctions (TJs) are the outermost structures of intercellular junctions and are highly specialized membrane domains involved in many important cellular processes. However, most TJ proteins are four-time transmembrane proteins and are difficult to express in their correct soluble form, which limits their functional study and therapeutic application. Human occludin (OCLN) is a major component of TJs and an essential co-receptor for hepatitis C virus (HCV) cell entry. To explore expression strategy for recombinant TJ proteins possessing integrated and functional extracellular loops, OCLN was here used as a model molecule, and several prokaryotic fusion constructs were designed by docking OCLN extracellular loops (ECLs) to HIV-1 gp41 NHR and CHR six-helical bundle (6HV1); then their biophysical features and anti-HCV activity were evaluated...
2017: PloS One
https://www.readbyqxmd.com/read/28447708/protein-collapse-is-encoded-in-the-folded-state-architecture
#3
Himadri S Samanta, Pavel I Zhuravlev, Michael Hinczewski, Naoto Hori, Shaon Chakrabarti, D Thirumalai
Folded states of single domain globular proteins are compact with high packing density. The radius of gyration, Rg, of both the folded and unfolded states increase as N(ν) where N is the number of amino acids in the protein. The values of the Flory exponent ν are, respectively, ≈⅓ and ≈0.6 in the folded and unfolded states, coinciding with those for homopolymers. However, the extent of compaction of the unfolded state of a protein under low denaturant concentration (collapsibility), conditions favoring the formation of the folded state, is unknown...
April 27, 2017: Soft Matter
https://www.readbyqxmd.com/read/28447293/shielding-of-the-geomagnetic-field-reduces-hydrogen-peroxide-production-in-human-neuroblastoma-cell-and-inhibits-the-activity-of-cuzn-superoxide-dismutase
#4
Hai-Tao Zhang, Zi-Jian Zhang, Wei-Chuan Mo, Ping-Dong Hu, Hai-Min Ding, Ying Liu, Qian Hua, Rong-Qiao He
Accumulative evidence has shown the adverse effects of a geomagnetic field shielded condition, so called a hypomagnetic field (HMF), on the metabolic processes and oxidative stress in animals and cells. However, the underlying mechanism remains unclear. In this study, we evaluate the role of HMF on the regulation of cellular reactive oxygen species (ROS) in human neuroblastoma SH-SY5Y cells. We found that HMF exposure led to ROS decrease, and that restoring the decrease by additional H2O2 rescued the HMF-enhanced cell proliferation...
April 26, 2017: Protein & Cell
https://www.readbyqxmd.com/read/28445752/refolding-of-sds-unfolded-proteins-by-nonionic-surfactants
#5
Jørn Døvling Kaspersen, Anne Søndergaard, Daniel Jhaf Madsen, Daniel E Otzen, Jan Skov Pedersen
The strong and usually denaturing interaction between anionic surfactants (AS) and proteins/enzymes has both benefits and drawbacks: for example, it is put to good use in electrophoretic mass determinations but limits enzyme efficiency in detergent formulations. Therefore, studies of the interactions between proteins and AS as well as nonionic surfactants (NIS) are of both basic and applied relevance. The AS sodium dodecyl sulfate (SDS) denatures and unfolds globular proteins under most conditions. In contrast, NIS such as octaethylene glycol monododecyl ether (C12E8) and dodecyl maltoside (DDM) protect bovine serum albumin (BSA) from unfolding in SDS...
April 25, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28445649/high-serum-stability-of-collagen-hybridizing-peptides-and-their-fluorophore-conjugates
#6
Lucas L Bennink, Daniel J Smith, Catherine A Foss, Martin G Pomper, Yang Li, S Michael Yu
Collagen hybridizing peptides (CHPs) have a great potential for use in targeted drug delivery, diagnostics, and regenerative medicine due to their ability to specifically bind to denatured collagens associated with many pathologic conditions. Since peptides generally suffer from poor enzymatic stability resulting in rapid degradation and elimination in vivo, CHP's serum stability is a critical parameter that may dictate its pharmacokinetic behavior. Here, we report the serum stability of a series of monomeric CHP derivatives and establish how peptide length, amino acid composition, terminal modification, and linker chemistry influence their availability in serum...
April 26, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/28439287/rattlesnake-crotalus-molossus-nigrescens-venom-induces-oxidative-stress-on-human-erythrocytes
#7
David Meléndez-Martínez, Juan Manuel Muñoz, Guillermo Barraza-Garza, Martha Sandra Cruz-Peréz, Ana Gatica-Colima, Emilio Alvarez-Parrilla, Luis Fernando Plenge-Tellechea
BACKGROUND: Globally, snake envenomation is a well-known cause of death and morbidity. In many cases of snakebite, myonecrosis, dermonecrosis, hemorrhage and neurotoxicity are present. Some of these symptoms may be provoked by the envenomation itself, but others are secondary effects of the produced oxidative stress that enhances the damage produced by the venom toxins. The only oxidative stress effect known in blood is the change in oxidation number of Fe (from ferrous to ferric) in hemoglobin, generating methemoglobin but not in other macromolecules...
2017: Journal of Venomous Animals and Toxins Including Tropical Diseases
https://www.readbyqxmd.com/read/28438316/multiple-modes-of-capillary-electrophoresis-applied-in-peptide-nucleic-acid-related-study
#8
Xiaoqian Wang, Youhao Hu, Feng Qu, Rizwan Ullah Khan
Peptide Nucleic Acid (PNA) is a nucleic acid analogue, whose neutrally charged and hydrophobic backbone makes it more stable in vivo, so it might act as a potentially better protein probe as compared to aptamer. Currently the investigation of PNA and protein interaction is scarce. In this research, multiple modes of capillary electrophoresis were established and applied for PNA characterization and its interaction with ssDNA and protein. A 15-mer PNA having the same nucleobase sequence as 15-mer anti-thrombin DNA aptamer was chosen as PNA model for this study, its pI (7...
April 17, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28438083/supplemental-feeding-of-a-gut-microbial-metabolite-of-linoleic-acid-10-hydroxy-cis-12-octadecenoic-acid-alleviates-spontaneous-atopic-dermatitis-and-modulates-intestinal-microbiota-in-nc-nga-mice
#9
Hiroko Kaikiri, Junki Miyamoto, Takahiro Kawakami, Si-Bum Park, Nahoko Kitamura, Shigenobu Kishino, Yasunori Yonejima, Keiko Hisa, Jun Watanabe, Tasuku Ogita, Jun Ogawa, Soichi Tanabe, Takuya Suzuki
The present study investigated the antiallergic and anti-inflammatory effects of 10-hydroxy-cis-12-octadecenoic acid (HYA), a novel gut microbial metabolite of linoleic acid, in NC/Nga mice, a model of atopic dermatitis (AD). Feeding HYA decreased the plasma immunoglobulin E level and skin infiltration of mast cells with a concomitant decrease in dermatitis score. HYA feeding decreased TNF-α and increased claudin-1, a tight junction protein, levels in the mouse skin. Cytokine expression levels in the skin and intestinal Peyer's patches cells suggested that HYA improved the Th1/Th2 balance in mice...
April 24, 2017: International Journal of Food Sciences and Nutrition
https://www.readbyqxmd.com/read/28436442/thermal-stability-storage-and-release-of-proteins-with-tailored-fit-in-silica
#10
Yun-Chu Chen, Tristan Smith, Robert H Hicks, Aswin Doekhie, Francoise Koumanov, Stephen A Wells, Karen J Edler, Jean van den Elsen, Geoffrey D Holman, Kevin J Marchbank, Asel Sartbaeva
Biological substances based on proteins, including vaccines, antibodies, and enzymes, typically degrade at room temperature over time due to denaturation, as proteins unfold with loss of secondary and tertiary structure. Their storage and distribution therefore relies on a "cold chain" of continuous refrigeration; this is costly and not always effective, as any break in the chain leads to rapid loss of effectiveness and potency. Efforts have been made to make vaccines thermally stable using treatments including freeze-drying (lyophilisation), biomineralisation, and encapsulation in sugar glass and organic polymers...
April 24, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28432913/spontaneously-formed-redox-and-ph-sensitive-polymersomes-by-mpeg-based-cytocompatible-random-copolymers
#11
Partha Laskar, Joykrishna Dey, Sudip Kumar Ghosh
Stimuli-sensitive polymersomes are one of the important vehicles and have been extensively studied as smart drug delivery system. Polymersomes have added advantage over the micelles because of having the ability to carry not only hydrophobic but also hydrophilic guest in their aqueous core. Among various stimuli, the change of pH and redox reaction is very important for drug delivery purpose especially for anticancer drug. Therefore, in this work, two poly(ethylene glycol) methyl ether methacrylate (mPEG) containing hydrophilic random anionic copolymers, poly[(2-hydroxyethyl methacrylate-3,3'-dithiodipropanoic acid)x-co-(poly(ethylene glycol) methyl ether methacrylate)y], poly[(HEMA-DTDPA)x-co-mPEGy] with different copolymer ratios were designed and synthesized...
April 12, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28432656/collisional-cross-sections-with-t-wave-ion-mobility-spectrometry-without-experimental-calibration
#12
Daniel N Mortensen, Anna C Susa, Evan R Williams
A method for relating traveling-wave ion mobility spectrometry (TWIMS) drift times with collisional cross-sections using computational simulations is presented. This method is developed using SIMION modeling of the TWIMS potential wave and equations that describe the velocity of ions in gases induced by electric fields. The accuracy of this method is assessed by comparing the collisional cross-sections of 70 different reference ions obtained using this method with those obtained from static drift tube ion mobility measurements...
April 21, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28431324/achievable-separation-performance-and-analysis-time-in-current-liquid-chromatographic-practice-for-monoclonal-antibody-separations
#13
Szabolcs Fekete, Jean-Luc Veuthey, Davy Guillarme
The separation performance of a chromatographic system is often described in terms of column efficiency and peak capacity. Thanks to the new developments in column technology over the past few years, the achievable peak capacity drastically improved and the analysis time can be significantly shortened. Indeed, highly efficient wide-pore reversed-phase (RPLC) materials packed with small fully porous and superficially porous particles can be successfully used for the analytical characterization of therapeutic proteins...
April 12, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28430241/probing-the-germination-kinetics-of-ethanol-treated-bacillus-thuringiensis-spores
#14
Guiwen Wang, Huanjun Chen, Xiaochun Wang, Lixin Peng, Yuan Peng, Yong-Qing Li
Bacillus thuringiensis (Bt) is the most widely used microbial insecticide. To clarify the mechanism of bacterial resistance to ethanol toxicity, the present study investigated the effects of 70% (v/v) ethanol at a moderate temperature (65°C) on Bt spore germination by single-cell Raman spectroscopy and differential interference contrast microscopy. We found that over 80% of Bt spores were inviable after 30 min of treatment. Moreover, ethanol treatment affected spore germination; the time for initiation of rapid calcium dipicolinate (CaDPA) release (i...
April 20, 2017: Applied Optics
https://www.readbyqxmd.com/read/28429932/thermodynamics-of-the-thermal-denaturation-of-acid-molten-globule-state-of-cytochrome-c-indicate-a-reversible-high-temperature-oligomerization-process
#15
Shigeyoshi Nakamura, Tomonori Saotome, Akiko Nakazawa, Masao Fukuda, Yutaka Kuroda, Shun-Ichi Kidokoro
In this study, we performed differential scanning calorimetry (DSC) and pressure perturbation calorimetry (PPC) analysis of the thermal transition of cytochrome c from an acidic molten globule (MG) state with the protein concentrations of 0.5-18.2 mg/mL. DSC profiles were highly reversible and showed clear protein-concentration dependence, indicating that reversible oligomerization occurred accompanying the thermal transition from the MG state. The DSC and PPC data required at least a six-state model including three new oligomeric states: dimer (I2), trimer (I3), and tetramer (I4) in addition to the three monomeric states previously characterized...
April 21, 2017: Biochemistry
https://www.readbyqxmd.com/read/28429809/successful-pegylation-of-hollow-encapsulin-nanoparticles-from-rhodococcus-erythropolis-n771-without-affecting-their-disassembly-and-reassembly-properties
#16
Seiichi Sonotaki, Taku Takami, Keiichi Noguchi, Masafumi Odaka, Masafumi Yohda, Yoshihiko Murakami
We developed a hollow PEGylated encapsulin nanoparticle from Rhodococcus erythropolis N771. The hollow engineered encapsulin nanoparticles with His-Tag and Lys residues on the surface were constructed by means of genetic recombination. The Lys residues on the particle surface were successfully PEGylated with a PEG derivative, methoxy-PEG-SCM. Consequently, we demonstrated that the hollow PEGylated engineered encapsulin nanoparticle could successfully disassemble or reassemble even after PEGylation in the presence or absence of a protein denaturing agent...
April 21, 2017: Biomaterials Science
https://www.readbyqxmd.com/read/28427288/cigarette-smokers-develop-altered-erythrocyte-membrane-composition-an-investigation-unmasking-the-role-of-membrane-bound-integral-protein-glut-1
#17
Jyotirmoy Sikdar, Paromita Seal, Amartya Roy, Rajen Haldar
Erythrocytes in cigarette smokers are prone to oxidative damage. Here we sought to elucidate the facts behind modifications and possible defense system developed in erythrocyte of cigarette smokers. We observed significant increase in stomatocytes and spherocytes, and osmotic fragility of erythrocyte, along with reduced level of protein thiol and increased fluorescence anisotropy in isolated membrane. Denaturing gel electrophoresis indicated alterations in band 3, band 4.2 and band 4.5. Among those, Glut 1 (i...
April 20, 2017: Free Radical Research
https://www.readbyqxmd.com/read/28427262/melting-proteins-evidence-for-multiple-stable-structures-upon-thermal-denaturation-of-native-ubiquitin-from-ion-mobility-spectrometry-mass-spectrometry-measurements
#18
Tarick J El-Baba, Daniel W Woodall, Shannon A Raab, Daniel R Fuller, Arthur Laganowsky, David H Russell, David E Clemmer
Ion mobility and mass spectrometry techniques are coupled with a temperature-controlled electrospray ionization source to follow the structural transitions of ubiquitin in aqueous solution (pH = 3) at elevated solution temperatures (T = 26-96 °C). Changes in the charge state distribution are consistent with a two-state, cooperative unfolding transition having a melting temperature of Tm = 71 ± 2 °C, in agreement with prior measurements [ Wintrode , P. L. ; Makhatadze , G. I. ; Privalov , P. L. Proteins , 1994 , 18 , 246 - 253 ]...
April 26, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28426809/denaturation-of-proteins-by-surfactants-studied-by-the-taylor-dispersion-analysis
#19
Aldona Jelińska, Anna Zagożdżon, Marcin Górecki, Agnieszka Wisniewska, Jadwiga Frelek, Robert Holyst
We showed that the Taylor Dispersion Analysis (TDA) is a fast and easy to use method for the study of denaturation proteins. We applied TDA to study denaturation of β-lactoglobulin, transferrin, and human insulin by anionic surfactant sodium dodecyl sulfate (SDS). A series of measurements at constant protein concentration (for transferrin was 1.9 x 10-5 M, for β- lactoglobulin was 7.6 x 10-5 M, and for insulin was 1.2 x 10-4 M) and varying SDS concentrations were carried out in the phosphate-buffered saline (PBS)...
2017: PloS One
https://www.readbyqxmd.com/read/28425008/reversible-activation-of-halophilic-%C3%AE-lactamase-from-methanol-induced-inactive-form-contrast-to-irreversible-inactivation-of-non-halophilic-counterpart
#20
Hiroko Tokunaga, Junpei Maeda, Tsutomu Arakawa, Masao Tokunaga
Effects of a water-miscible organic solvent, methanol, on the structure and activity of halophilic β-lactamase derived from Chromohalobacter sp.560 (HaBla), were investigated by means of circular dichroism (CD) measurement and enzymatic activity determination. Beta-lactamase activity was enhanced about 1.2-fold in the presence of 10-20% methanol. CD measurement of HaBla revealed different structures depending on the methanol concentration: native-like active form (Form I) in 10-20% methanol and methanol-induced inactive form at higher concentration (Form II in 40-60% and Form III in 75-80% methanol)...
April 20, 2017: Protein Journal
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