Synthesis of "Nereid," a new phenol-free detergent to replace Triton X-100 in virus inactivation.

In the 1980s, virus inactivation steps were implemented into the manufacturing of biopharmaceuticals in response to earlier unforeseen virus transmissions. The most effective inactivation process for lipid-enveloped viruses is the treatment by a combination of detergents, often including Triton X-100 (TX-100). Based on recent environmental concerns, the use of TX-100 in Europe will be ultimately banned, which forces the pharmaceutical industry, among others, to switch to an environmentally friendly alternative detergent with fully equivalent virus inactivation performance such as TX-100. In this study, a structure-activity relationship study was conducted that ultimately led to the synthesis of several new detergents. One of them, named "Nereid," displayed inactivation activity fully equivalent to TX-100. The synthesis of this replacement candidate has been optimized to allow for the production of several kg of detergent at lab scale, to enable the required feasibility and comparison virus inactivation studies needed to support a potential future transition. The 3-step, chromatography-free synthesis process described herein uses inexpensive starting materials, has a robust and simple work-up, and allows production in a standard organic laboratory to deliver batches of several hundred grams with >99% purity.

Steroid-Based Amphiphiles for Membrane Protein Study: The Importance of Alkyl Spacers for Protein Stability.

Membrane proteins allow effective communication between cells and organelles and their external environments. Maintaining membrane protein stability in a non-native environment is the major bottleneck to their structural study. Detergents are widely used to extract membrane proteins from the membrane and to keep the extracted protein in a stable state for downstream characterisation. In this study, three sets of steroid-based amphiphiles-glyco-diosgenin analogues (GDNs) and steroid-based pentasaccharides either lacking a linker (SPSs) or containing a linker (SPS-Ls)-have been developed as new chemical tools for membrane protein research. These detergents were tested with three membrane proteins in order to characterise their ability to extract membrane proteins from the membrane and to stabilise membrane proteins long-term. Some of the detergents, particularly the SPS-Ls, displayed favourable behaviour with the tested membrane proteins. This result indicates the potential utility of these detergents as chemical tools for membrane protein structural study and a critical role of the simple alkyl spacer in determining detergent efficacy.

A comparative study of branched and linear mannitol-based amphiphiles on membrane protein stability.

The study of membrane proteins is extremely challenging, mainly because of the incompatibility of the hydrophobic surfaces of membrane proteins with an aqueous medium. Detergents are essential agents used to maintain membrane protein stability in non-native environments. However, conventional detergents fail to stabilize the native structures of many membrane proteins. Development of new amphipathic agents with enhanced efficacy for membrane protein stabilization is necessary to address this important problem. We have designed and synthesized linear and branched mannitol-based amphiphiles (MNAs), and comparative studies showed that most of the branched MNAs had advantages over the linear agents in terms of membrane protein stability. In addition, a couple of the new MNAs displayed favorable behaviors compared to n-dodecyl-ß-d-maltoside and the previously developed MNAs in maintaining the native protein structures, indicating potential utility of these new agents in membrane protein study.

Dodecyl-ß-melibioside Detergent Micelles as a Medium for Membrane Proteins.

There remains a need for new non-ionic detergents that are suitable for use in biochemical and biophysical studies of membrane proteins. Here we explore the properties of n-dodecyl-ß-melibioside (ß-DDMB) micelles as a medium for membrane proteins. Melibiose is d-galactose-α(1→6)-d-glucose. Light scattering showed the ß-DDMB micelle to be roughly 30 kDa smaller than micelles formed by the commonly used n-dodecyl-ß-maltoside (ß-DDM). ß-DDMB stabilized diacylglycerol kinase (DAGK) against thermal inactivation. Moreover, activity assays conducted using aliquots of DAGK purified into ß-DDMB yielded activities that were 40% higher than those of DAGK purified into ß-DDM. ß-DDMB yielded similar or better TROSY-HSQC NMR spectra for two single-pass membrane proteins and the tetraspan membrane protein peripheral myelin protein 22. ß-DDMB appears be a useful addition to the toolbox of non-ionic detergents available for membrane protein research.

Highly Branched Pentasaccharide-Bearing Amphiphiles for Membrane Protein Studies.

Detergents are essential tools for membrane protein manipulation. Micelles formed by detergent molecules have the ability to encapsulate the hydrophobic domains of membrane proteins. The resulting protein-detergent complexes (PDCs) are compatible with the polar environments of aqueous media, making structural and functional analysis feasible. Although a number of novel agents have been developed to overcome the limitations of conventional detergents, most have traditional head groups such as glucoside or maltoside. In this study, we introduce a class of amphiphiles, the PSA/Es with a novel highly branched pentasaccharide hydrophilic group. The PSA/Es conferred markedly increased stability to a diverse range of membrane proteins compared to conventional detergents, indicating a positive role for the new hydrophilic group in maintaining the native protein integrity. In addition, PDCs formed by PSA/Es were smaller and more suitable for electron microscopic analysis than those formed by DDM, indicating that the new agents have significant potential for the structure-function studies of membrane proteins.

Synthesis of uniformly deuterated n-dodecyl-ß-D-maltoside (d39-DDM) for solubilization of membrane proteins in TROSY NMR experiments.

This work reports the first synthesis of uniformly deuterated n-dodecyl-ß-D-maltoside (d39-DDM). DDM is a mild non-ionic detergent often used in the extraction and purification of membrane proteins and for solubilizing them in experimental studies of their structure, dynamics and binding of ligands. We required d39-DDM for solubilizing large α-helical membrane proteins in samples for [(15)N-(1)H]TROSY (transverse relaxation-optimized spectroscopy) NMR experiments to achieve the highest sensitivity and best resolved spectra possible. Our synthesis of d39-DDM used d7-D-glucose and d25-n-dodecanol to introduce deuterium labelling into both the maltoside and dodecyl moieties, respectively. Two glucose molecules, one converted to a glycosyl acceptor with a free C4 hydroxyl group and one converted to a glycosyl donor substituted at C1 with a bromine in the α-configuration, were coupled together with an α(1 → 4) glycosidic bond to give maltose, which was then coupled with n-dodecanol by its substitution of a C1 bromine in the α-configuration to give DDM. (1)H NMR spectra were used to confirm a high level of deuteration in the synthesized d39-DDM and to demonstrate its use in eliminating interfering signals from TROSY NMR spectra of a 52-kDa sugar transport protein solubilized in DDM.

CHOBIMALT: a cholesterol-based detergent.

Cholesterol and its hemisuccinate and sulfate derivatives are widely used in studies of purified membrane proteins but are difficult to solubilize in aqueous solution, even in the presence of detergent micelles. Other cholesterol derivatives do not form conventional micelles and lead to viscous solutions. To address these problems, a cholesterol-based detergent, CHOBIMALT, has been synthesized and characterized. At concentrations above 3−4 µM, CHOBIMALT forms micelles without the need for elevated temperatures or sonic disruption. Diffusion and fluorescence measurements indicated that CHOBIMALT micelles are large (210±30 kDa). The ability to solubilize a functional membrane protein was explored using a G-protein coupled receptor, the human kappa opioid receptor type 1 (hKOR1). While CHOBIMALT alone was not found to be effective as a surfactant for membrane extraction, when added to classical detergent micelles CHOBIMALT was observed to dramatically enhance the thermal stability of solubilized hKOR1.

Identification and characterization of a Triton X-100 replacement for virus inactivation.

Triton X-100 detergent treatment is a robust enveloped virus inactivation unit operation included in biopharmaceutical manufacturing processes. However, the European Commission officially placed Triton X-100 on the Annex XIV authorization list in 2017 because a degradation product of Triton X-100, 4-(1,1,3,3-tetramethylbutyl) phenol (also known as 4-tert-octylphenol), is considered to have harmful endocrine disrupting activities. As a result, the use of Triton X-100 in the European Economic Area (EEA) would not be allowed unless an ECHA issued authorization was granted after the sunset date of January 4, 2021. This has prompted biopharmaceutical manufacturers to search for novel, environment-friendly alternative detergents for enveloped virus inactivation. In this study, we report the identification of such a novel detergent, Simulsol SL 11W. Simulsol SL 11W is an undecyl glycoside surfactant produced from glucose and C11 fatty alcohol. We report here that Simulsol SL 11W was able to effectively inactive enveloped viruses, such as xenotropic murine leukemia virus (XMuLV) and pseudorabies virus (PRV). By using XMuLV as a representative enveloped virus, the influence of various parameters on the effectiveness of virus inactivation was evaluated. Virus inactivation by Simulsol SL 11W was effective across different clarified bioreactor harvests at broad concentrations, pH, and temperature ranges. Simulsol SL 11W concentration, temperature of inactivation, and treatment time were identified as critical process parameters for virus inactivation. Removal of Simulsol SL 11W was readily achieved by Protein A chromatography and product quality was not affected by detergent treatment. Taken together, these results have shown the potential of Simulsol SL 11W as a desirable alternative to Triton X-100 for enveloped virus inactivation that could be readily implemented into biopharmaceutical manufacturing processes.

Structure at 2.5 A of a designed peptide that maintains solubility of membrane proteins.

A 24-amino acid peptide designed to solubilize integral membrane proteins has been synthesized. The design was for an amphipathic alpha helix with a "flat" hydrophobic surface that would interact with a transmembrane protein as a detergent. When mixed with peptide, 85 percent of bacteriorhodopsin and 60 percent of rhodopsin remained in solution over a period of 2 days in their native forms. The crystal structure of peptide alone showed it to form an antiparallel four-helix bundle in which monomers interact, flat surface to flat surface, as predicted.

Conformationally Restricted Monosaccharide-Cored Glycoside Amphiphiles: The Effect of Detergent Headgroup Variation on Membrane Protein Stability.

Detergents are widely used to isolate membrane proteins from lipid bilayers, but many proteins solubilized in conventional detergents are structurally unstable. Thus, there is major interest in the development of novel amphiphiles to facilitate membrane protein research. In this study, we have designed and synthesized novel amphiphiles with a rigid scyllo-inositol core, designated scyllo-inositol glycosides (SIGs). Varying the headgroup structure allowed the preparation of three sets of SIGs that were evaluated for their effects on membrane protein stability. When tested with a few model membrane proteins, representative SIGs conferred enhanced stability to the membrane proteins compared to a gold standard conventional detergent (DDM). Of the novel amphiphiles, a SIG designated STM-12 was most effective at preserving the stability of the multiple membrane proteins tested here. In addition, a comparative study of the three sets suggests that several factors, including micelle size and alkyl chain length, need to be considered in the development of novel detergents for membrane protein research. Thus, this study not only describes new detergent tools that are potentially useful for membrane protein structural study but also introduces plausible correlations between the chemical properties of detergents and membrane protein stabilization efficacy.

Lipopeptide detergents designed for the structural study of membrane proteins.

The structural study of membrane proteins requires detergents that can effectively mimic lipid bilayers, and the choice of detergent is often a compromise between detergents that promote protein stability and detergents that form small micelles. We describe lipopeptide detergents (LPDs), a new class of amphiphile consisting of a peptide scaffold that supports two alkyl chains, one anchored to each end of an alpha-helix. The goal was to design a molecule that could self-assemble into a cylindrical micelle with a rigid outer hydrophilic shell surrounding an inner lipidic core. Consistent with this design, LPDs self-assemble into small micelles, can disperse phospholipid membranes, and are gentle, nondenaturing detergents that preserve the structure of the membrane proteins in solution for extended periods of time. The LPD design allows for a membrane-like packing of the alkyl chains in the core of the molecular assemblies, possibly explaining their superior properties relative to traditional detergents in stabilizing membrane protein structures.

Preparation of benzalkonium salts differing in the length of a side alkyl chain.

Benzalkonium salts are widely used as disinfectants, biocides and detergents,among a variety of other applications. The cationic surface-activity of these salts determines their potential to act as a biocide on both target and non-target organisms. In this study, a quick synthesis of a complete set of the benzalkonium salts differing in the length of an alkylating chain (from C(2) to C(20)) is described. Moreover, their (1)H-NMR, HPLC-MS, TLC and HPLC analysis were recorded.

Usability of an Alcohol Disinfectant Containing Organic Acids and Metal Salt for Environmental Surfaces.

Environmental cleaning and disinfection plays an important role as a part of the standard precautions to prevent healthcare-associated infections, whereas hand hygiene is one of the most important strategies for breaking the chain of transmission. Cleaning and disinfection of high-touch areas in a health-care facility is emphasized. And wiping with an alcohol-saturated cloth which has features such as low corrosion and a wide range of antimicrobial activity is performed commonly for this purpose. Although alcohol provides immediate activity against enveloped viruses, its virucidal activity against certain non-enveloped viruses, including norovirus, is insufficient. We created a novel alcohol-based hand rub, MR06B7, which is safe for the skin, and is active against an extended spectrum of microorganisms including non-enveloped viruses. For environmental surface disinfection, a novel disinfectant MR13B15, which is based on MR06B7, has been developed. In vitro antimicrobial activity against a variety of pathogens, material compatibility, and simulated surface disinfection and decontamination efficacy of MR13B15 were investigated. According to the results, MR13B15 demonstrated potent bactericidal, fungicidal, mycobactericidal, and virucidal activity within a short contact time in addition to superior efficacy against non-enveloped viruses compared to ethanol for disinfection. Moreover, MR13B15 showed better material compatibility. Two simulation tests conducted for evaluating the disinfection and decontamination potency on environmental surfaces against feline calicivirus, a surrogate for norovirus, indicated that MR13B15 had superior efficacy for surface treatment compared to ethanol. These findings suggest that MR13B15, which satisfies most requirements of an environmental surface disinfectant, may contribute to accomplishing advanced standard precautions in preventing infections.

Synthesis of phospholipid-based detergents and their effects on the Ca(2+)-ATPase of sarcoplasmic reticulum.

Phospholipid molecules containing a cholate or hemisuccinylcholate moiety at the 2-position were synthesized as possible detergents for solubilization of membrane proteins. 1-Myristoleoyl-2-cholyl-sn-glycero-3- phosphatidylcholine ((C14:1,cholyl)PC) was found to solubilize sarcoplasmic reticulum vesicles at concentrations above its cmc of ca. 4 micrograms/ml. Effects of (C14:1,cholyl)PC on the activity of the Ca(2+)-ATPase of sarcoplasmic reticulum were complex, as for other detergents. High concentrations (0.2 mg/ml) of (C14:1,cholyl)PC were able to displace phospholipids from the lipid/protein interface of the ATPase. Although under these conditions the activity of the ATPase was low, the ATPase was not denatured since activity could be regained by displacement of (C14:1,cholyl)PC with the detergent C12E8. 1-oleoyl-2-cholyl-sn-glycero-3-phosphatidylcholine ((C18:1,cholyl)PC) was found to have a very low water solubility, but this could be increased by the introduction of a hemisuccinyl group to give 1-oleoyl-2-(3 alpha-hemisuccinyl)cholyl-sn-glycero-3-phosphatidylcholine ((C18:1,cholylCOOH)PC). This was able to solubilize and delipidate the Ca(2+)-ATPase; the ATPase was stable in (C18:1,cholylCOOH)PC for long periods of time.

The use of octyl beta-D-glucoside as detergent for hog kidney brush border membrane.

Octyl beta-D-glucoside was synthetized from alpha-acetobromoglucose with an improved method yielding a very pure product with a sharp melting point (108-109 degrees C) and free of intermediate products as judged by IR and NMR spectra. The yield of the synthesis is 66% when referred to alpha-acetobromoglucose. The potency of this compound as a detergent on hog kidney brush border membranes was compared to the action of Triton X-100. Octyl glucoside preferentially extracts aminopeptidase M and gamma-glutamyltranspeptidase in a concentration-dependent manner. The more deeply imbedded membrane enzyme, alkaline phosphatase, was relatively resistent to the action of octyl glucoside. In contrast, Triton X-100 extracted all membrane proteins to about the same extent. Additionally it was found that octyl glucoside can be removed from membrane extracts by Biobead SM 2. The capacity of the beads is about 170 mg detergent/g of dry Biobead SM 2. Thus octyl glucoside seems to be a useful tool for solubilization and purification of brush border membranes proteins.

CHAPSTEROL. A novel cholesterol-based detergent.

Design, synthesis and characterization of CHAPSTEROL, a novel cholesterol-based detergent developed for functional solubilization of cholesterol-dependent membrane proteins are described. To validate CHAPSTEROL, we employed the oxytocin receptor, a G protein-coupled receptor requiring cholesterol for its high-affinity binding state. Using the photoactivatable cholesterol analogue [3H]6,6-azocholestan-3beta-ol[3alphaH], we demonstrate that solubilization by CHAPSTEROL leads to an enrichment of cholesterol-binding proteins whereas the widely used bile acid derivative CHAPSO leads to a significant depletion of cholesterol-binding proteins. Similar to Triton X-100 and CHAPS, CHAPSTEROL maintains the localization of caveolin as well as cholesterol and sphingomyelin to lipid rafts, i.e. detergent-insoluble microdomains of the plasma membrane. The data suggest that CHAPSTEROL is an appropriate detergent for the solubilization of cholesterol-dependent membrane proteins and isolation of rafts.

Nonacid cleavable detergents applied to MALDI mass spectrometry profiling of whole cells.

Although cleavable detergents were first synthesized a number of years ago, they have only recently been successfully applied to problems involving biological molecules. Recent reports have demonstrated that these compounds are useful for applications involving both 2D PAGE and mass spectrometry. However, most cleavable surfactants have utilized acid-labile functional groups to affect cleavage. In applications where extreme pH is required, acid cleavable detergents have limited usefulness. We report the synthesis of fluoride cleavable silane compounds and photolabile cinnamate esters as cleavable detergents having alternative cleavage chemistries than previously reported cleavable detergents. These compounds were applied to whole cell analysis using MALDI mass spectrometry, and it was demonstrated that their use results in an increase in the number of proteins analyzed by increasing protein solubility.

Integrated synthesis of zeolites 4A and Na-P1 using coal fly ash for application in the formulation of detergents and swine wastewater treatment.

Several researchers have reported zeolite synthesis using coal ash for a wide range of applications. However, little attention has been given to green processes, including moderate synthesis conditions, using waste as raw material and effluent reuse or reduction. In this study, Brazilian coal fly ashes were used for integrated synthesis of zeolites 4A and Na-P1 by two different routes and under moderate operating conditions (temperature and pressure). Both procedures produced zeolites with similar conversions (zeolite 4A at 82% purity and zeolite Na-P1 at 57-61%) and high CEC values (zeolites 4A: 4.5meqCa(2+)g(-1) and zeolites Na-P1: 2.6-2.8meqNH4(+)g(-1)). However, process 1 generated less effluent for the zeolite mass produced (7mLg(-1)), with low residual Si and Al levels and 74% of the Si available in the coal fly ash incorporated into the zeolite, while only 55% is used in process 2. For use as a builder in detergents, synthetic zeolite 4A exhibited conformity parameters equal to or greater than those of the commercial zeolite adopted as reference. Treatment of swine wastewater with zeolite Na-P1 resulted in a high removal capacity for total ammoniacal nitrogen (31mgg(-1)).

Advances in protease engineering for laundry detergents.

Proteases are essential ingredients in modern laundry detergents. Over the past 30 years, subtilisin proteases employed in the laundry detergent industry have been engineered by directed evolution and rational design to tailor their properties towards industrial demands. This comprehensive review discusses recent success stories in subtilisin protease engineering. Advances in protease engineering for laundry detergents comprise simultaneous improvement of thermal resistance and activity at low temperatures, a rational strategy to modulate pH profiles, and a general hypothesis for how to increase promiscuous activity towards the production of peroxycarboxylic acids as mild bleaching agents. The three protease engineering campaigns presented provide in-depth analysis of protease properties and have identified principles that can be applied to improve or generate enzyme variants for industrial applications beyond laundry detergents.

Are Lipases Still Important Biocatalysts? A Study of Scientific Publications and Patents for Technological Forecasting.

The great potential of lipases is known since 1930 when the work of J. B. S. Haldane was published. After eighty-five years of studies and developments, are lipases still important biocatalysts? For answering this question the present work investigated the technological development of four important industrial sectors where lipases are applied: production of detergent formulations; organic synthesis, focusing on kinetic resolution, production of biodiesel, and production of food and feed products. The analysis was made based on research publications and patent applications, working as scientific and technological indicators, respectively. Their evolution, interaction, the major players of each sector and the main subject matters disclosed in patent documents were discussed. Applying the concept of technology life cycle, S-curves were built by plotting cumulative patent data over time to monitor the attractiveness of each technology for investment. The results lead to a conclusion that the use of lipases as biocatalysts is still a relevant topic for the industrial sector, but developments are still needed for lipase biocatalysis to reach its full potential, which are expected to be achieved within the third, and present, wave of biocatalysis.