Read by QxMD icon Read

Protein denaturation

Alexander Tischer, Venkata R Machha, Jörg Rösgen, Matthew Auton
Protein phase diagrams have a unique potential to identify the presence of additional thermodynamic states even when non-2-state character is not readily apparent from the experimental observables used to follow protein unfolding transitions. Two-state analysis of the von Willebrand factor A3 domain has previously revealed a discrepancy in the calorimetric enthalpy obtained from thermal unfolding transitions as compared with Gibbs-Helmholtz analysis of free energies obtained from the Linear Extrapolation Method (Tischer and Auton, Prot Sci 2013; 22(9):1147-60)...
February 19, 2018: Biopolymers
Sho Imoto, Harald Forbert, Dominik Marx
Solvation of trimethylamine-N-oxide (TMAO) by water is of great fundamental interest because this small molecule has both strongly hydrophilic and large hydrophobic groups at its opposite ends and, furthermore, stabilizes proteins against temperature and pressure denaturation. Since hydrophilic and hydrophobic groups affect the structural dynamics of the respective solvation water molecules in vastly different ways, we dissect their distinct influences on the THz spectrum of TMAO(aq) by using ab initio molecular dynamics simulations...
February 19, 2018: Physical Chemistry Chemical Physics: PCCP
Longfa Jiang, Shengjun Wu
This study aims to investigate the effect of pullulan on the denaturation of the myofibrillar protein of grass carp (Ctenopharyngodon idella) during frozen storage at -18 °C for 30 days. Pullulan or commercial cryoprotectant (1 g dry weight) were added to 100 g of the myofibrillar protein of grass carp (C. idella), respectively, which was frozenly stored at -18 °C for 30 days, and the changes in the state of unfrozen of water, solubility, Ca 2+ -adenylpyrophosphatase (ATP ase ) activity, and sulfhydryl content of myofibrils were monitored during frozen storage...
February 14, 2018: International Journal of Biological Macromolecules
Fabrice Rose, Kasper Karlsen, Pernille Rønde Jensen, Rasmus Uffe Jakobsen, Grith Krøyer Wood, Kasper Dyrberg Rand, Helene Godiksen, Peter Andersen, Frank Follmann, Camilla Foged
Sexually transmitted Chlamydia trachomatis (Ct) infects more than 100 million people annually, and untreated chlamydia infections can cause severe complications. Therefore, there is an urgent need for a chlamydia vaccine. The Ct major outer membrane protein (MOMP) is highly immunogenic but is a challenging vaccine candidate by being an integral membrane protein, and the immunogenicity depends on a correctly folded structure. We investigated the biophysical properties of the recombinant MOMP-based fusion antigen CTH522, which is tested in early human clinical trials...
February 13, 2018: Journal of Pharmaceutical Sciences
Dan F Smelter, Willem J De Lange, Wenxuan Cai, Ying Ge, John C Ralphe
Cardiac myosin binding protein-C (cMyBP-C) is a functional sarcomeric protein that regulates contractility in response to contractile demand, and many mutations in cMyBP-C lead to hypertrophic cardiomyopathy (HCM). To gain insight into the effects of disease-causing cMyBP-C missense mutations on contractile function, we expressed the pathogenic W792R mutation in mouse cardiomyocytes lacking endogenous cMyBP-C and studied the functional effects using three-dimensional engineered cardiac tissue (mECT) constructs...
February 16, 2018: American Journal of Physiology. Heart and Circulatory Physiology
Vijay Kumar Reddy Surasani, Tanaji Kudre, Rajashekhar V Ballari
Study was conducted to recover proteins from pangas (Pangasius pangasius) processing waste (fillet frames) using pH shift method and to characterize the recovered isolates. pH 2.0 from acidic range and pH 13.0 from alkaline range were found to have maximum protein recovery (p < 0.05). During the recovery process, acidic pH (pH 2.0) was found to have minimal effect on proteins resulting in more stable isolates and strong protein gels. Alkaline pH (pH 13.0) caused protein denaturation resulting in less stable proteins and poor gel network...
February 15, 2018: Environmental Science and Pollution Research International
Paul Grassein, Patrice Delarue, Harold Abraham Scheraga, Gia G Maisuradze, Patrick Senet
Protein folding/unfolding can be analysed experimentally at a local scale by monitoring the physical properties of local probes as a function of the temperature, as for example the distance between fluorophores or the values of chemical shifts of backbone atoms. Here, the analytical Lifson-Roig model for the helix-coil transition is modified to analyse local thermal unfolding of the fast-folder W protein of bacteriophage lambda (gpW) simulated by all-atom molecular dynamics (MD) simulations in explicit solvent at fifteen different temperatures...
February 15, 2018: Journal of Physical Chemistry. B
Héctor Capella-Monsonís, João Q Coentro, Valeria Graceffa, Zhuning Wu, Dimitrios I Zeugolis
Collagen type I is the most abundant extracellular matrix protein, and collagen type I supramolecular assemblies (e.g., tissue grafts, biomaterials and cell-assembled systems) are used extensively in tissue engineering and regenerative medicine. Many studies, for convenience or economic reasons, do not accurately determine collagen type I purity, concentration, solubility and extent of cross-linking in biological specimens, frequently resulting in erroneous conclusions. In this protocol, we describe solubility; normal, reduced and delayed (interrupted) SDS-PAGE; hydroxyproline; Sircol collagen and Pierce BCA protein; denaturation temperature; ninhydrin/trinitrobenzene sulfonic acid; and collagenase assays and assess them in a diverse range of biological samples (e...
March 2018: Nature Protocols
S Hamidreza Arabi, Behdad Aghelnejad, Christian Schwieger, Annette Meister, Andreas Kerth, Dariush Hinderberger
We report extended pH- and temperature-induced preparation procedures and explore the materials and molecular properties of different types of hydrogels made from human and bovine serum albumin, the major transport protein in the blood of mammals. We describe the diverse range of properties of these hydrogels at three levels: (1) their viscoelastic (macroscopic) behavior, (2) protein secondary structure changes during the gelation process (via ATR-FTIR spectroscopy), and (3) the hydrogel fatty acid (FA) binding capacity and derive from this the generalized tertiary structure through CW EPR spectroscopy...
February 15, 2018: Biomaterials Science
Xiangyu Gu, Jiaxin Peng
Graphene oxide nanosheets was prepared, modification with 3-aminopropyltriethoxysilane and used as the carrier for immobilization of NADH oxidase (NOX) from Streptococcus mutans. The prepared nanosheets were characterized with FTIR. A high immobilization yield of 92% and activity recovery of 91% were achieved at pH 7.0 and 25 °C. The thermostability of the immobilized NOX was improved about 60% compared with the free enzyme. And the immobilized NOX preserved about 92% of its initial activity after 500 h storage at 4 °C, while free NOX was totally denatured after 200 h at the same conditions...
June 1, 2018: Journal of Nanoscience and Nanotechnology
S Jóhannsdóttir, P Saokham, A Magnúsdóttir, T Loftsson
Cyclosporine A (CyA) is a lipophilic oligopeptide that has a very limited solubility in water of only 0.008 mg/ml at ambient temperature. It has the ability to form inclusion complexes with cyclodextrin (CD) whose complexes can self-assemble to form aggregates. We have previously developed eye drops with CyA/CD aggregates. Our aim was to study cyclodextrin complexes of lysozyme, a small polar globular protein, and to compare the results with those obtained for CyA. We also wanted to test the stabilizing effect of CDs on lysozyme...
October 1, 2017: Die Pharmazie
Ana Paula Black, Juliana S Anjos, Ludmila Cardozo, Flávia L Carmo, Carla J Dolenga, Lia S Nakao, Dennis de Carvalho Ferreira, Alexandre Rosado, José Carlos Carraro Eduardo, Denise Mafra
OBJECTIVES: To evaluate the effects of low-protein diet (LPD) on uremic toxins and the gut microbiota profile in nondialysis chronic kidney disease (CKD) patients. DESIGN AND METHODS: Longitudinal study with 30 nondialysis CKD patients (stage 3-4) undergoing LPD for 6 months. Adherence to the diet was evaluated based on the calculation of protein equivalent of nitrogen appearance from the 24-hour urine analysis. Good adherence to LPD was considered when protein intake was from 90% to 110% of the prescribed amount (0...
February 10, 2018: Journal of Renal Nutrition
Shosuke Ito, Kazumasa Wakamatsu
-4-(4-hydroxyphenyl)-2-butanol (rhododendrol (RD))-a skin-whitening ingredient-was reported to induce leukoderma in some consumers. We have examined the biochemical basis of the RD-induced leukoderma by elucidating the metabolic fate of RD in the course of tyrosinase-catalyzed oxidation. We found that the oxidation of racemic RD by mushroom tyrosinase rapidly produces RD-quinone, which gives rise to secondary quinone products. Subsequently, we confirmed that human tyrosinase is able to oxidize both enantiomers of RD...
February 12, 2018: International Journal of Molecular Sciences
Anna Vitlin Gruber, Milena Vugman, Abdussalam Azem, Celeste E Weiss
Chaperonins are large, essential, oligomers that facilitate protein folding in chloroplasts, mitochondria, and eubacteria. Plant chloroplast chaperonins are comprised of multiple homologous subunits that exhibit unique properties. We previously characterized homogeneous, reconstituted, chloroplast-chaperonin oligomers in vitro, each composed of one of three highly homologous beta subunits from A. thaliana. In the current work, we describe alpha-type subunits from the same species and investigate their interaction with β subtypes...
2018: Frontiers in Molecular Biosciences
Mirjam C L Peek, Feng Wu
High-intensity focused ultrasound (HIFU) is a minimally invasive technique that has been used for the treatment of both benign and malignant tumours. With HIFU, an ultrasound (US) beam propagates through soft tissue as a high-frequency pressure wave. The US beam is focused at a small target volume, and due to the energy building up at this site, the temperature rises, causing coagulative necrosis and protein denaturation within a few seconds. HIFU is capable of providing a completely non-invasive treatment without causing damage to the directly adjacent tissues...
2018: Ecancermedicalscience
Willy Yee, Janushree Nanda Kumar, Priya Devi Muthusamy
2-mercaptoethanol (2-ME), alongside polyvinylpyrrolidone is commonly used in plant DNA extractions to deal with polyphenols, which could interfere with extraction and downstream applications. 2-ME is also commonly used to denature proteins and nucleases, especially RNAses. On the contrary, we found that the presence of 2-ME in lysis buffer interfered with DNA extraction from 12 strains of freshwater microalgae, resulting in DNA with poor integrity. We also found that the TNES-urea buffer, commonly used for preservation and DNA extraction from fish, appears as effective as the SDS and CTAB buffer for some microalgae strains...
March 2018: Indian Journal of Microbiology
Adrian O Olivares, Tania A Baker, Robert T Sauer
AAA+ proteolytic machines use energy from ATP hydrolysis to degrade damaged, misfolded, or unneeded proteins. Protein degradation occurs within a barrel-shaped self-compartmentalized peptidase. Before protein substrates can enter this peptidase, they must be unfolded and then translocated through the axial pore of an AAA+ ring hexamer. An unstructured region of the protein substrate is initially engaged in the axial pore, and conformational changes in the ring, powered by ATP hydrolysis, generate a mechanical force that pulls on and denatures the substrate...
February 10, 2018: Annual Review of Physiology
M R Sanders, H E Findlay, P J Booth
α-Helical membrane proteins have eluded investigation of their thermodynamic stability in lipid bilayers. Reversible denaturation curves have enabled some headway in determining unfolding free energies. However, these parameters have been limited to detergent micelles or lipid bicelles, which do not possess the same mechanical properties as lipid bilayers that comprise the basis of natural membranes. We establish reversible unfolding of the membrane transporter LeuT in lipid bilayers, enabling the comparison of apparent unfolding free energies in different lipid compositions...
February 5, 2018: Proceedings of the National Academy of Sciences of the United States of America
Maximilian K G Ehrhardt, Suzanne L Warring, Monica L Gerth
Identifying the ligands sensed by chemoreceptors remains challenging, in part because current screening methods are low-throughput, costly, and/or time-consuming. In contrast, fluorescence thermal shift (FTS) assays provide a fast and inexpensive approach to chemoreceptor-ligand screening. In FTS assays, the temperature at which a protein denatures is measured by monitoring the fluorescence of a dye with affinity for hydrophobic regions of the protein, which are exposed as the protein unfolds. A detectable increase (or "shift") in the melting temperature (T m ) of the protein in the presence of a potential ligand indicates binding...
2018: Methods in Molecular Biology
Liyan Liu, Zerong Lu, Lin Li, Bing Li, Xia Zhang, Ximei Zhang, Zhenbo Xu
OBJECTIVE: This study aimed to investigate the physical relation and mechanism of bactericidal activity on pathogenic E. coli by ultrasonic field with whey protein isolate (WPI). METHODS: Ultrasound treatment was performed under the conditions of intensity at 65 W/cm2, pulse duty ratio at 0.5 for 0-15 min with WPI concentration ranged from 0 to 10%. Viscosity, granularity, surface hydrophobicity, free radical scavenging activity, and thermal denaturation were assessed by rotational viscometer, Malvern Mastersizer 2000 particle size analyzer, fluorescent probe ANS method, DPPH method, and differential scanning calorimetry, respectively...
February 8, 2018: Microbial Pathogenesis
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"