sodium-dodecyl-sulfate and hexylene-glycol

The influence of different parameters on the silicification procedure using lysozyme is reported. When polyethoxysiloxane (PEOS), an internally crosslinked silica reservoir, is used, regular structures with a narrow size distribution could be obtained only via introducing the silica precursor in two steps including initial dropping and subsequent addition of residual oil phase in one portion. We found that mixing sequence of mineralizing agents in the presence of a positively charged surfactant plays a key role in terms of silica precipitation when tetraethoxyorthosilicate (TEOS) is the oil phase. In contrast, well-mineralized crumpled features with high specific surface area could be synthesized in the presence of PEOS as a silica precursor polymer, regardless of mixing sequence. Moreover, introducing sodium dodecyl sulfate (SDS) as a negatively charged surfactant resulted in regular silica sphere formation only in combination with hexylene glycol (MPD) as a specific co-solvent. Finally, it is demonstrated that by inclusion of different nanoparticles even more sophisticated hybrid materials can be generated.

Topics: Adsorption; Animals; Cetrimonium; Cetrimonium Compounds; Chemistry Techniques, Synthetic; Chickens; Glycols; Muramidase; Nanoparticles; Particle Size; Silicon Dioxide; Siloxanes; Sodium Dodecyl Sulfate; Surface Properties; Surface-Active Agents

The development of efficient protein refolding techniques remains a challenge in biotechnology. In that context, it has recently been reported that the addition of 2-methyl-2, 4-pentanediol (MPD) to sodium dodecyl sulfate (SDS) allows the renaturation of both soluble and membrane proteins. The present work combines experimental (dynamic light scattering; DLS) and theoretical (molecular dynamics) approaches to study the molecular basis of the association between SDS and MPD, in order to understand its relevance in the refolding process. DLS shows the micelle dissociation in the presence of molar concentrations of MPD, and simulations reveal that this process results from a screening of the negative charge on the SDS headgroup and a minimization of the solvent (water) accessibility of the detergent tail. This suggests a mechanism whereby the combination of these effects leads to the shift from a "harsh" to a "gentle" detergent behavior, which in turn promotes a productive refolding of the protein.

Topics: Glycols; Hydrogen Bonding; Light; Micelles; Molecular Dynamics Simulation; Scattering, Radiation; Sodium Dodecyl Sulfate; Time Factors

Currently, the investigation of protein refolding processes involves several time-consuming stages that require large amounts of protein and costly chemicals. Consequently, there is great interest in developing new approaches to the study of protein renaturation that are more technically and economically feasible. It has recently been reported that certain cosolvents are able to modulate the denaturing properties of sodium dodecyl sulfate (SDS) and induce the refolding of proteins. This unit presents a protocol to study and follow the renaturation of a protein (membrane or soluble) starting from a native or SDS-unfolded state using a variety of candidate cosolvents and osmolytes.

Topics: Detergents; Enzyme Assays; Glycols; Muramidase; Osmolar Concentration; Protein Denaturation; Protein Renaturation; Proteins; Sodium Dodecyl Sulfate; Solutions; Solvents

Glutathione S-transferase (GST) is widely used to prepare and purify GSTtagged fusion proteins. Although GST improves protein solubility, detergents must often be used to achieve protein solubilization from bacterial lysates. However, purification of GST by affinity chromatography cannot be achieved in the presence of even low concentrations of the detergent sodium dodecyl sulfate (SDS). Here we show that 2-methyl-2,4-pentanediol (MPD) can prevent SDS from interfering with purification of GST, thus enabling purification of proteins that require SDS to improve their solubility.

Topics: Chromatography, Affinity; Escherichia coli; Glutathione Transferase; Glycols; Recombinant Fusion Proteins; Sodium Dodecyl Sulfate; Solubility

Enzymatic reactions involving bilayer lipids occur in an environment with strict physical and topological constraints. The integral membrane enzyme PagP transfers a palmitoyl group from a phospholipid to lipid A in order to assist Escherichia coli in evading host immune defenses during infection. PagP measures the palmitoyl group with an internal hydrocarbon ruler that is formed in the interior of the eight-stranded antiparallel β barrel. The access and egress of the palmitoyl group is thought to take a lateral route from the bilayer phase to the barrel interior. Molecular dynamics, mutagenesis, and a 1.4 A crystal structure of PagP in an SDS / 2-methyl-2,4-pentanediol (MPD) cosolvent system reveal that phospholipid access occurs at the crenel present between strands F and G of PagP. In this way, the phospholipid head group can remain exposed to the cell exterior while the lipid acyl chain remains in a predominantly hydrophobic environment as it translocates to the protein interior.

Topics: Acyltransferases; Bacterial Outer Membrane Proteins; Binding Sites; Circular Dichroism; Crystallography; Escherichia coli Proteins; Glycols; Lipid A; Models, Molecular; Phospholipids; Protein Conformation; Sodium Dodecyl Sulfate; Solvents

Patients receiving radiation therapy due to oral cancer develop complications such as hyposalivation, mucositis, oral infections, dental hypersensitivity and caries. Mouthrinses can alleviate some of these problems.. To investigate the in vitro antimicrobial properties and cytotoxicity of an experimental mouthrinse.. The mouthrinse contained 30% hexylene glycol (glycerine), 7% potassium nitrate and 0.025% sodium fluoride. The minimal inhibitory concentration (MIC) of these ingredients and the mixture was determined for C. albicans, S. aureus and S. mutans over 24 hours at different concentrations. The MICs of two commercial mouthrinses, Corsodyl and Plax, were also determined using the same organisms. All mouthrinses were then tested to determine the percentage kill over 1, 2, and 3 minutes.. The MICs for hexylene glycol were 10%, 30% and 10% for C. albicans, S. aureus and S. mutons respectively. Potassium nitrate and sodium fluoride had no antimicrobial effects. The MIC of Corsodyl was 0.016 mg/ml for all the test organisms. The MIC for Plax varied from 0.0002 mg/ml to 0.001 mg/ml. The kill rates for all mouthrinses were acceptable, with no statistical differences between them. The experimental mouthrinse was not toxic to human oesophageal SCC cells after 1 minute exposure. At the time of the experiment, the costs of a similar quantity of the experimental mouthrinse, Corsodyl and Plax were R5.24, R30.00 and R10.00 respectively.. The experimental mouthrinse was cost-effective and proved to have an antimicrobial effect and could be used safely to alleviate oral infections, desensitize teeth, improve oral hygiene and control dental caries in cancer patients after radiation therapy.

Topics: Anti-Infective Agents, Local; Benzoates; Candida albicans; Carcinoma, Squamous Cell; Cariostatic Agents; Cell Adhesion; Cell Line, Tumor; Chlorhexidine; Dentin Desensitizing Agents; Dose-Response Relationship, Drug; Esophageal Neoplasms; Glycols; Humans; Lubricants; Materials Testing; Microbial Sensitivity Tests; Mouthwashes; Nitrates; Potassium Compounds; Radiotherapy; Sodium Dodecyl Sulfate; Sodium Fluoride; Staphylococcus aureus; Streptococcus mutans; Time Factors; Triclosan

Recently, we reported a unique approach to preserve the activity of some proteins in the presence of the denaturing agent, Sodium Dodecyl Sulfate (SDS). This was made possible by addition of the amphipathic solvent 2,4-Methyl-2-PentaneDiol (MPD), used as protecting but also as refolding agent for these proteins. Although the persistence of the protein activity in the SDS/MPD mixture was clearly established, preservation of their structure was only speculative until now.. In this paper, a detailed X-ray study addresses the pending question. Crystals of hen egg-white lysozyme were grown for the first time in the presence of MPD and denaturing concentrations of SDS. Depending on crystallization conditions, tetragonal crystals in complex with either SDS or MPD were collected. The conformation of both structures was very similar to the native lysozyme and the obtained complexes of SDS-lysozyme and MPD-lysozyme give some insights in the interplay of protein-SDS and protein-MPD interactions.. This study clearly established the preservation of the enzyme structure in a SDS/MPD mixture. It is hypothesized that high concentrations of MPD would change the properties of SDS and lower or avoid interactions between the denaturant and the protein. These structural data therefore support the hypothesis that MPD avoids disruption of the enzyme structure by SDS and can protect proteins from SDS denaturation.

Topics: Animals; Chickens; Crystallization; Crystallography, X-Ray; Glycols; Muramidase; Protein Conformation; Protein Denaturation; Sodium Dodecyl Sulfate; Solvents; Surface-Active Agents

Sodium dodecyl sulfate (SDS) is a highly effective and widely used protein denaturant. We show that certain amphipathic cosolvents such as 2-methyl-2,4-pentanediol (MPD) can protect proteins from SDS denaturation, and in several cases can refold proteins from the SDS-denatured state. This cosolvent effect is observed with integral membrane proteins and soluble proteins from either the alpha-helical or the beta-sheet structural classes. The SDS/MPD system can be used to study processes involving native protein states, and we demonstrate the reversible thermal denaturation of the outer membrane protein PagP in an SDS/MPD buffer. MPD and related cosolvents can modulate the denaturing properties of SDS, and we describe a simple and effective method to recover refolded, active protein from the SDS-denatured state.

Topics: Acyltransferases; Animals; Bacterial Outer Membrane Proteins; Bacteriorhodopsins; Buffers; Carbonic Anhydrase II; Chickens; Dose-Response Relationship, Drug; Escherichia coli Proteins; Glycols; Halobacterium salinarum; Hot Temperature; Humans; Hydrophobic and Hydrophilic Interactions; Inclusion Bodies; Muramidase; Protein Conformation; Protein Denaturation; Protein Folding; Protein Renaturation; Protein Structure, Secondary; Sodium Dodecyl Sulfate; Solubility; Solvents; Surface-Active Agents