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Uncontrollable growth of Zn dendrites, irreversible dissolution of cathode material and solidification of aqueous electrolyte at low temperatures severely restrict the development of aqueous Zn‐ion batteries. In this work, 2,2,2‐trifluoroethanol (TFEA) with a volume fraction of 50% as a highly compatible polar‐solvent is introduced to 1.3 M Zn(CF3SO3)2 aqueous electrolyte, achieving stable high‐performance Zn‐ion batteries. Massive theoretical calculations and characterization analysis demonstrate that TFEA weakens the tip effect of Zn anode and restrains the growth of Zn dendrites due to electrostatic adsorption and coordinate with H2O to disrupt the hydrogen bonding network in water. Furthermore, TFEA increases the wettability of the cathode and alleviates the dissolution of V2O5, thus improving the capacity of the full battery. Based on those positive effects of TFEA on Zn anode, V2O5 cathode, and aqueous electrolyte, the Zn//Zn symmetric cell delivers a long cycle‐life of 782 h at 5 mA cm−2 and 2 mA h cm−2. The full battery still declares an initial capacity of 116.78 mA h g−1, and persists 87.73% capacity in 2000 cycles at −25 °C. This work presents an effective strategy for fully compatible co‐solvent to promote the stability of Zn anode, V2O5 cathode and aqueous electrolyte for high‐performance Zn‐ion batteries. [ABSTRACT FROM AUTHOR]

Here, An efficient approach to obtaining previously unknown furo[2′,3′:2,3]pyrrolo[2,1-a]isoquinoline derivatives from readily available 1-R-1-ethynyl-2-vinylisoquinolines is described. The reaction features a simple procedure, occurs in hexaflouroisopropanol and does not require elevated temperatures. It has been found that the addition of glacial acetic acid significantly increases the yields of the target spirolactone products. Using trifluoroethanol instead of hexaflouroisopropanol results in the formation of pyrido[2,1-a]isoquinolines. [ABSTRACT FROM AUTHOR]

The cosolvent 2,2,2‐trifluoroethanol (TFE) is often used to mimic protein desiccation. We assessed the effects of TFE on cytosolic abundant heat soluble protein D (CAHS D) from tardigrades. CAHS D is a member of a unique protein class that is necessary and sufficient for tardigrades to survive desiccation. We find that the response of CAHS D to TFE depends on the concentration of both species. Dilute CAHS D remains soluble and, like most proteins exposed to TFE, gains α‐helix. More concentrated solutions of CAHS D in TFE accumulate β‐sheet, driving both gel formation and aggregation. At even higher TFE and CAHS D concentrations, samples phase separate without aggregation or increases in helix. Our observations show the importance of considering protein concentration when using TFE. [ABSTRACT FROM AUTHOR]

Membrane proteins are one of the keystone objects in molecular biology, but their structural studies often require an extensive search for an appropriate membrane-like environment and an efficient refolding protocol for a recombinant protein. Isotropic bicelles are a convenient membrane mimetic used in structural studies of membrane proteins. Helical membrane domains are often transferred into bicelles from trifluoroethanol–water mixtures. However, the protocols for such a refolding are empirical and the process itself is still not understood in detail. In search of the optimal refolding approaches for helical membrane proteins, we studied here how membrane proteins, lipids, and detergents interact with each other at various trifluoroethanol–water ratios. Using high-resolution NMR spectroscopy and dynamic light scattering, we determined the key states of the listed compounds in the trifluoroethanol/water mixture, found the factors that could be critical for the efficiency of refolding, and proposed several most optimal protocols. These protocols were developed on the transmembrane domain of neurotrophin receptor TrkA and tested on two model helical membrane domains—transmembrane of Toll-like receptor TLR9 and voltage-sensing domain of a potassium channel KvAP. [ABSTRACT FROM AUTHOR]

Here, An efficient approach to obtaining previously unknown furo[2′,3′:2,3]pyrrolo[2,1-a]isoquinoline derivatives from readily available 1-R-1-ethynyl-2-vinylisoquinolines is described. The reaction features a simple procedure, occurs in hexaflouroisopropanol and does not require elevated temperatures. It has been found that the addition of glacial acetic acid significantly increases the yields of the target spirolactone products. Using trifluoroethanol instead of hexaflouroisopropanol results in the formation of pyrido[2,1-a]isoquinolines.

Thermo-reversible gel of myofibrillar protein (MP) can be made by tactics of elaborate deamidation using protein-glutaminase (PG), and this work aimed to disclose the link between thermally reversible gelation of MP and the coiled-coil (CC). Enzymatic deamidation fragmented myofibril filaments and triggered structural reassembly to create small-sized aggregates. The coiling and dissociation of CC structure in the myosin tails is the fundamental structural basis of the PG deamidated MP (DMP) in the dynamic evolution of reversible gelation. After specific inhibition of CC assembly by trifluoroethanol (TFE), the thermo-reversible gel ability of DMP was impaired, which confirmed that the dynamic assembly of CC with temperature response played a key role in the thermo-reversible gelation of DMP. The findings may broaden the molecular basis of natural CC reversible gelation and foster advances for the development of new muscle protein products.

Alpha-Synuclein is a presynaptic neuronal protein whose masses are involved in Parkinson's disease, a chronic and progressive neurodegenerative disorder of the central nervous system. It has been observed that upon exposure to anionic surfactants, fluorinated alcohols and membranes in vitro, α -synuclein adopts alpha helix structure and can be fibrillated, while in aqueous solution, the protein is intrinsically disordered and the fibrillation is undesirable. Solvent is one of the most critical environmental parameters in biological studies as well as computer simulations. In this paper, we have investigated the effect of solvent composition on the conformation of α -synuclein protein using molecular dynamics (MD) simulations. For this purpose, the effect of different combinations of water and trifluoroethanol (TFE) solvents on the secondary structure of a fragment of α -synuclein was investigated. Moreover, thermodynamic calculations were performed through a coarse-grained (CG) model of solutions with different concentrations of α -synuclein in the aqueous phase and in TFE medium. The potential of mean force (PMF) calculations was performed as a function of separation distance between the centers of masses of two peptides. The results indicated that in the presence of TFE, the secondary structures have a regular arrangement of amino acids stabilized by hydrogen bonding patterns. In addition, decreasing the TFE concentration reduces the stability of α -helix structures of the protein. It seems that in diluted TFE solutions, high concentrations of water in the medium lead to the breakage of peptide–TFE hydrogen bonds. However, the hydrophobic nature of TFE and α -synuclein molecules prevents further aggregation in the concentrated solutions. The α-synuclein can be fibrillated in the presence of Trifluoroethanol (TFE). Stability of α-helix structure of peptide reduces as TFE concentration decreases. Hydrophobic nature of TFE and α-synuclein molecules prevents further aggregation. [ABSTRACT FROM AUTHOR]

An approach based on experimental and theoretical methods was used to compare the self‐assembly [i.e., determination of the critical micelle concentration (CMC), degree of ionization (α) and counterion binding (β)] of sodium dodecyl sulfate (SDS) and didodecyl dimethyl ammonium bromide (DDAB) in deionized water and 10 mM NaCl and 10 (vol) % trifluoroethanol solutions. Experimental methods consisted of electrical conductometry, tensiometry, fluorimetry, and determination of Krafft temperature. A critical analysis of the thermodynamics of self‐assembly by the Gibbs–Helmholtz equation and the van't‐Hoff rationale provided values of several parameters, such as the change of Gibbs free energy and enthalpy change of micellization (ΔGm0 and ΔHm0, respectively) and the Gibbs free energy of surfactant tail groups (∆G0trans). Interfacial properties, aggregation number (Nagg), micropolarity (I1/I3), microviscosity (η), packing parameter (P), dielectric constant (D), anisotropy (r), and Stern–Volmer binding constant (KSV) for SDS and DDAB in different temperatures and different systems were determined. [ABSTRACT FROM AUTHOR]

An efficient decarboxylative addition reaction of β‐ketoacids with miscellaneous electrophiles in 2,2,2‐trifluoroethanol (TFE) is reported. The reaction proceeds smoothly without any base and metal catalysts, affording a broad range of diarylmethanes, β‐hydroxy ketones and 3,3‐disubstituted oxindoles with moderate to excellent yields under essentially neutral conditions. [ABSTRACT FROM AUTHOR]

Viperin, an antiviral protein, has been shown to contain a CX(3)CX(2)C motif, which is conserved in the radical S-adenosyl-methionine (SAM) enzyme family. A triple mutant which replaces these three cysteines with alanines has been shown to have severe deficiency in antiviral activity. Since the crystal structure of Viperin is not available, we have used a combination of computational methods including multi-template homology modeling and molecular dynamics simulation to develop a low-resolution predicted structure. The results show that Viperin is an α-β protein containing iron-sulfur cluster at the center pocket. The calculations suggest that the removal of iron-sulfur cluster would lead to collapse of the protein tertiary structure. To verify these predictions, we have prepared, expressed and purified four mutant proteins. In three mutants individual cysteine residues were replaced by alanine residues while in the fourth all the cysteines were replaced by alanines. Conformational analyses using circular dichroism and steady state fluorescence spectroscopy indicate that the mutant proteins are partially unfolded, conformationally unstable and aggregation prone. The lack of conformational stability of the mutant proteins may have direct relevance to the absence of their antiviral activity.

A facile sol-gel method was proposed to prepare fluorine-containing hydrophobic SiO2 coating using trifluoroethanol (TFE) as the dispersant and hydrophobic modifier simultaneously. FTIR and XPS analysis indicated that CF3 groups were incorporated onto the surface of SiO2 particles. The resultant SiO2 coating possessed excellent hydrophobicity with a water contact angle (WCA) of 145°. This provides a new method for the preparation of fluorine-containing sol-gel SiO2 coating without the expensive long-chain alkyl fluorosilane.

Lactams are essential compounds in medicinal chemistry and key intermediates in the synthesis of natural products. The Castagnoli–Cushman reaction (CCR) of homophthalic anhydride with imines is an exciting method for accessing cyclic densely substituted lactam products. Most CCRs need to be catalyzed or heated. Herein, we report a new, efficient, metal and catalyst-free CCR for the synthesis of poly-substituted 3,4-lactams utilizing the unique properties of trifluoroethanol (TFE). This procedure provides high-speed and smooth access to a broad range of densely substituted 3,4-lactams in good yields and a 100% atom-economical fashion.

The ability of antibodies to switch between specific and nonspecific recognition of antigens under various factors is the key issue. Here we demonstrate that 2,2,2-trifluoroethanol (TFE) is one of these factors influencing the ability of monoclonal antibodies to react specifically with corresponding antigen (ovalbumin) and transforming them into polyreactive immunoglobulins (PRIGs) that are strong but nonspecific binders with various antigens. Such switching of antibody reactivity is nonlinear and even nonmonotonous function of TFE concentration and depends strongly on incubation time and temperature. At room temperatures (25 °C) the specific antibodies under 30% TFE action are transformed into PRIGs. However, at 0 °C the variation of antibody reactivity is complicated. TFE is known as the alcohol with one of the strongest proton-donor abilities in hydrogen bonding and its effect is probably in binding to specific sites that switch the antibody recognition ability.

Fluorinated alcohols have been widely used in the synthetic organic chemistry over the past decades. The unique properties such as the strong hydrogen‐bonding donor ability and low nucleophilicity allow them to promote organic reactions in the absence of any catalyst. These approaches have distinct advantages in terms of operational simplicity, practicability and environmental friendliness. Reactions promoted by fluorinated alcohols, including nucleophilic substitution reactions, annulation reactions, electrophilic reactions, dearomatization reactions, functionalization of multiple bond, epoxidation reactions and miscellaneous reactions have been summarized in this account. [ABSTRACT FROM AUTHOR]

Amyloid beta-protein (Abeta) fibril assembly is a defining characteristic of Alzheimer's disease. Fibril formation is a complex nucleation-dependent polymerization process characterized in vitro by an initial lag phase. To a significant degree, this phase is a consequence of the energy barrier that must be overcome in order for Abeta monomers to fold and oligomerize into fibril nuclei. Here we show that low concentrations of 2,2,2-trifluoroethanol (TFE) convert predominately unstructured Abeta monomers into partially ordered, quasistable conformers. Surprisingly, this results in a temporal decrease in the lag phase for fibril formation and a significant increase in the rate of fibril elongation. The TFE effect is concentration dependent and is maximal at approximately 20% (v/v). In the presence of low concentrations of TFE, fibril formation is observed in Abeta samples at nanomolar concentration, well below the critical concentration for Abeta fibril formation in the absence of TFE. As the amount of TFE is increased above 20%, helix content progressively rises to approximately 80%, a change paralleled first by a decrease in elongation rate and then by a complete cessation of fibril growth. These findings are consistent with the hypothesis that a partially folded helix-containing conformer is an intermediate in Abeta fibril assembly. The requirement that Abeta partially folds in order to assemble into fibrils contrasts with the mechanism of amyloidogenesis of natively folded proteins such as transthyretin and lysozyme, in which partial unfolding is a prerequisite. Our results suggest that in vivo, factors that affect helix formation and stability will have significant effects on the kinetics of Abeta fibril formation.

Abstract Steady state and time resolved spectral properties of 7,8-benzoquinoline (7,8-BQ) have been reinvestigated in a series of organic solvents of different proticity, polarity and wide range of pH. The salient features of this work are the effect of hydrogen bonding in protonation reaction which is explored through its behaviour in water and strong hydrogen bond donating solvent (trifluoroethanol). Quantum yield and rates (radiative, non-radiative and excited state protonation) have been calculated and discussed. Irreversible diffusion controlled excited state proton transfer in water and faster excited state protonation in trifluoroethanol is observed. Graphical abstract Graphical abstract indicating protonation of 7,8-BQ in water. Image 1017 Highlights • Steady state and time resolved properties of 7,8-benzoquinoline are reinvestigated. • Depending on media and pH, neutral and protonated species are present in the ground and excited states. • Irreversible diffusion controlled excited state proton transfer is observed in water. • Much faster excited state protonation is observed in trifluoroethanol. • Results indicate evidence of promoting of protonation by hydrogen bonding. [ABSTRACT FROM AUTHOR]

The synthesis of a molecularly diverse library of tetrasubstituted alkenes containing a barbiturate motif is described. Base-induced condensation of N1-substituted pyrimidine-2,4,6(1H,3H,5H)-triones with 5-(bis(methylthio)methylene)-2,2-dimethyl-1,3-dioxane-4,6-dione gave 3-substituted 5-(methylthio)-2H-pyrano[2,3-d]pyrimidine-2,4,7(1H,3H)-triones (‘pyranopyrimidinones’), regioselectively. A sequence of reactions involving ring-opening of the pyran moiety, displacement of the methylthio group with an amine, re-formation of the pyran ring, and after its final cleavage with an amine, gave tetrasubstituted alkenes (3-amino-3-(2,4,6-trioxotetrahydropyrimidin-5(2H)-ylidene)propanamides) with a diversity of substituents. Cleavage of the pyranopyrimidinones with an aniline was facilitated in 2,2,2-trifluoroethanol under microwave irradiation. Compounds were tested against Escherichia coli, Staphylococcus aureus, the yeast Schizosaccharomyces pombe, and the pathogenic fungus Candida albicans. No compounds exhibited activity against E. coli, whilst one compound was weakly active against S. aureus. Three compounds were strongly active against S. pombe, but none was active against C. albicans.

An angular displacement-enhanced heterodyne polarimeter has been employed to investigate the interplay between trifluoroethanol (TFE) and glycerol on the thermal denaturation of type I collagen. The concentration of the collagen solution was fixed at 0.341 (mg/mL), and was heated from 25 °C to 55 °C. TFE solutions with concentrations of 5%, 10%, 15%, 20%, 40% and 80% (v/v) were prepared and the phase change was recorded for the determination of thermal denaturation. It was observed that the thermal denaturation temperature (Td) is decreased with increasing TFE concentration due to the partial cleavage of the triple-helical structure. With TFE concentration higher than 20% (v/v), the degree of optical rotation appears to be nearly the same, reflecting that the collagen triple helices have been completely destructed. Moreover, the addition of glycerol in inhibiting the thermal denaturation of collagen is investigated. It has been shown that glycerol can improve the thermal denaturation of both collagen and TFE-mixed collagen. Experimental results show that, in the presence of 2 M glycerol, the Td of collagen remained at around 41.9 °C, meanwhile the Td of 20% (v/v) TFE-mixed collagen is significantly restored to 32.8 °C.

Thermo-reversible gel of myofibrillar protein (MP) can be made by tactics of elaborate deamidation using protein-glutaminase (PG), and this work aimed to disclose the link between thermally reversible gelation of MP and the coiled-coil (CC). Enzymatic deamidation fragmented myofibril filaments and triggered structural reassembly to create small-sized aggregates. The coiling and dissociation of CC structure in the myosin tails is the fundamental structural basis of the PG deamidated MP (DMP) in the dynamic evolution of reversible gelation. After specific inhibition of CC assembly by trifluoroethanol (TFE), the thermo-reversible gel ability of DMP was impaired, which confirmed that the dynamic assembly of CC with temperature response played a key role in the thermo-reversible gelation of DMP. The findings may broaden the molecular basis of natural CC reversible gelation and foster advances for the development of new muscle protein products., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Revised descriptors are determined for fifteen phthalate esters for use in the solvation parameter model and form part of the Wayne State University (WSU) compound descriptor database. For thirteen phthalate esters a comparison is made with the same compounds in the Abraham descriptor database. Gas chromatographic retention factors on poly(methyloctylsiloxane), SPB-Octyl, and poly(cyanopropylphenyldimethylsiloxane), DB-225, stationary phases are used to facilitate an assessment of the contribution of cavity formation and dispersion interactions, L descriptor, and dipole-type interactions, S descriptor, to the experimental retention factors (log k) for the phthalate esters with minimum interference from competing intermolecular interactions. The results indicate a systematic overprediction of the cavity and dispersion interaction term and underprediction of dipole-type interactions for the Abraham descriptors compared with the WSU descriptors for the phthalate esters. The average absolute deviation (AAD) for 13 phthalate esters on SPB-Octyl is 0.039 (WSU descriptors) compared with 0.252 (Abraham descriptors) and for 9 phthalate esters on DB-225 0.030 (WSU descriptors) compared with 0.167 (Abraham descriptors). The results for dipole-type interactions are confirmed and extended to include the hydrogen-bond basicity of the phthalate esters, B descriptor, by evaluation of partition constants in aqueous biphasic systems and the n-heptane-2,2,2-trifluoroethanol biphasic system. Differences in the contribution of the hydrogen-bond basicity of the phthalate esters to the experimental partition constants are largely random with respect to database selection but important for the accurate prediction of the partition constants. The AAD for the partition constant for 15 phthalate esters is 0.063 (WSU descriptors) compared with 0.320 (Abraham descriptors) for the heptane-2,2,2-trifluoroethanol biphasic system and 0.13 (WSU descriptors) compared with 0.25 (Abraham descriptors) for 9 phthalate esters in the octanol-water biphasic system. The WSU descriptors for the phthalate esters exhibit a better fit with the experimental data for separation systems and are free of the extreme values predicted for the Abraham descriptors for several phthalate esters., Competing Interests: Declaration of Competing Interest The author declares that he has no conflicts of interest in connection with this study., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The cosolvent 2,2,2-trifluoroethanol (TFE) is often used to mimic protein desiccation. We assessed the effects of TFE on cytosolic abundant heat soluble protein D (CAHS D) from tardigrades. CAHS D is a member of a unique protein class that is necessary and sufficient for tardigrades to survive desiccation. We find that the response of CAHS D to TFE depends on the concentration of both species. Dilute CAHS D remains soluble and, like most proteins exposed to TFE, gains α-helix. More concentrated solutions of CAHS D in TFE accumulate β-sheet, driving both gel formation and aggregation. At even higher TFE and CAHS D concentrations, samples phase separate without aggregation or increases in helix. Our observations show the importance of considering protein concentration when using TFE., (© 2023 The Protein Society.)

A novel protocol is reported for the N-formylation of amines with formic acid by using the nanoporous zeolitic imidazolate framework ZIF-8 as a heterogeneous catalyst in 2,2,2-trifluoroethanol. [ABSTRACT FROM AUTHOR]

The aza-Michael addition of functionally substituted anilines to enoates is significantly affected by the hydrogen bond donor ability of the solvent. Very polar protic fluorinated alcohols (hexafluoroisopropanol and trifluoroethanol) favor the addition of weak nucleophiles, whereas these solvents are no longer required for anilines bearing additional OH or NH 2 group. [ABSTRACT FROM AUTHOR]

An efficient and versatile mechanochemical route for the synthesis of chromene and isoindolo[2,1-a]quinazoline scaffolds has been developed via a simple mortar and pestle liquid-assisted grinding method using 2,2,2-trifluoroethanol (TFE) as an efficient catalyst. The present protocol is very efficient as it offers reaction in mild reaction condition, cleaner reaction profiles, effortless work-up step with excellent purity, and high yield of the desired products with short reaction time. [ABSTRACT FROM AUTHOR]

Abstract: Alterations in the local dynamics of Cu/Zn Superoxide dismutase (SOD1) due to mutations affect the protein folding, stability, and function leading to misfolding and aggregation seen in amyotrophic lateral sclerosis (ALS). Here, we study the structure and dynamics of the most devastating ALS mutation, A4V SOD1 in aqueous trifluoroethanol (TFE) through experiments and simulation. Far‐UV circular dichroism (CD) studies shows that TFE at intermediate concentrations (∼15% ‐ 30%) induce partially unfolded β‐sheet‐rich extended conformations in A4V SOD1 which subsequently aggregates. Molecular dynamics (MD) simulation results shows that A4V SOD1 increases local dynamics in the active site loops that leads to the destabilization of the β‐barrel and loss of hydrophobic contacts, thus stipulating a basis for aggregation. Free energy landscape (FEL) and essential dynamics (ED) analysis demonstrates the conformational heterogeneity in A4V SOD1. Our results thus shed light on the role of local unfolding and conformational dynamics in aggregation of SOD1. [ABSTRACT FROM AUTHOR]

[Display omitted] An efficient and green synthesis protocol has been developed for construction of triarylmethane scaffold using trifluoroethanol as a recyclable solvent. Significantly, recyclable solvent and product could be separated by filtration. The expected product could be afforded in good to excellent yield under standard conditions. Meanwhile, recyclable trifluoroethanol solvent could be reused directly for a new reaction. Furthermore, trifluoroethanol could be recovered through distillation with excellent yield, which can be used for other reaction. [ABSTRACT FROM AUTHOR]

Cold-regulated (COR) 15A is an intrinsically disordered protein (IDP) from Arabidopsis thaliana important for freezing tolerance. During freezing-induced cellular dehydration, COR15A transitions from a disordered to mostly α-helical structure. We tested whether mutations that increase the helicity of COR15A also increase its protective function. Conserved glycine residues were identified and mutated to alanine. Nuclear magnetic resonance (NMR) spectroscopy was used to identify residue-specific changes in helicity for wildtype (WT) COR15A and the mutants. Circular dichroism (CD) spectroscopy was used to monitor the coil–helix transition in response to increasing concentrations of trifluoroethanol (TFE) and ethylene glycol. The impact of the COR15A mutants on the stability of model membranes during a freeze–thaw cycle was investigated by fluorescence spectroscopy. The results of these experiments showed the mutants had a higher content of α-helical structure and the increased α-helicity improved membrane stabilization during freezing. Comparison of the TFE- and ethylene glycol-induced coil–helix transitions support our conclusion that increasing the transient helicity of COR15A in aqueous solution increases its ability to stabilize membranes during freezing. Altogether, our results suggest the conserved glycine residues are important for maintaining the disordered structure of COR15A but are also compatible with the formation of α-helical structure during freezing induced dehydration.

Asymmetric alkylation is one of the most useful carbon–carbon bond-forming reactions in synthetic organic chemistry. Chiral-amine-catalyzed alkylation reactions often lack regioselectivity owing to multiple reactive centers. In particular, the alkylation of linear 2-enals through dienamine catalysis produces a mixture of regioisomers owing to reactive α- and γ-positions. A few attempts have been made to mask the α-reactive center to achieve γ-selectivity. Controlling the enantioselectivity at the remote γ-position has also been found to be quite challenging. Herein, we achieved the highly regioselective γ-alkylation of linear α, β-unsaturated aldehydes by using trifluoroethanol (TFE) as a cosolvent. Further, we demonstrated in situ kinetic resolution for enantioenrichment of the γ-alkylated products. This method brings together the activation of an electrophile facilitated by TFE and in situ kinetic resolution to achieve excellent selectivity in dienamine catalysis. [ABSTRACT FROM AUTHOR]

Glucoamylase (EC 3.2.1.3) from Aspergillus niger possesses 31% α-helix, 36% β structure and rest aperiodic structure. A transition of glucoamylase structure in the presence of varying concentrations of glyoxal (GO) and trifluoroethanol (TFE) was studied by using multi-methodological approaches. At 20% GO, glucoamylase exists as molten globule state as evident by high tryptophan and ANS fluorescence, retention of secondary structure and loss of native tertiary structure. This state precedes the onset of the aggregation process and maximum is achieved at the highest concentration i.e . at 90% of GO. In parallel study TFE, on increasing concentration up to 25% induces secondary structure transformation leading to accumulation of intermolecular β sheets, altered tryptophan environment, high ANS and ThT fluorescence resulting in the formation of glucoamylase aggregates. Isothermal titration calorimetric curve is sigmoidal, indicating the weak binding of GO/TFE and glucoamylase. TEM studies showed that glucoamylase exists as globular and amorphous aggregates at 90% glyoxal and 25% TFE respectively. Further, TFE at 70% causes inhibition of enzyme aggregates; the majority of secondary structures observed at this concentration are α helices. Alpha helices being the main key player relocates glucoamylase native environment as evident by CD, FTIR and TEM. Hence induction of β sheet promotes protein aggregation and α helices inhibits protein aggregation. [ABSTRACT FROM AUTHOR]

It is shown that C4(S)-NH2 /OH/NHCHO-prolyl polypeptides exhibit PPII conformation in aqueous medium, but in a relatively hydrophobic solvent trifluoroethanol (TFE) transform into an unusual β-structure. The stereospecific directing effect of H-bonding in defining the specific structure is demonstrated by the absence of β-structure in the corresponding C4(S)-guanidinyl/(NH/O)-acetyl derivatives and retention of β-structure in C4(S)-(NHCHO)-prolyl polypeptides in TFE. The distinct conformations are identified by the characteristic CD patterns and supported by Raman spectroscopic data. The solvent dependent conformational effects are interpreted in terms of intraresidue H-bonding that promotes PPII conformation in water, switching over to interchain H-bonding in TFE. The present observations add a new design principle to the growing repertoire of strategies for engineering peptide secondary structural motifs for innovative nanoassemblies and new biomaterials. [ABSTRACT FROM AUTHOR]

• The indirect introduction of perfluoroalkyl groups into allene benzazecines has been developed. • The cytotoxic activity of perfluoroalkyl substituted compounds has been evaluated. • The reaction mechanistic features have been refined. New approach for the introduction of a perfluoroalkynyl fragment into 1-R2–2-methyl-1,2,3,4-tetrahydroisoquinolines has been developed. Synthesized 1,1-disubstituted isoquinoline compounds under the action of methyl propiolate (24 °C) and acetylacetylene (-17 °C) in trifluoroethanol are converted into 6-perfluoroalkyl substituted allene benzazecines. The synthesized isoquinoline derivatives 2 , and benzazecines 3 – 4 were evaluated against four cancer cell lines. The results revealed that compound 2h (R2 = C 6 H 4 - p -OMe; R F = CF(CF 3) 2) displayed good cytotoxic effects on four tested cell lines with IC 50 values ranging from 5 to 50 μM. To create your abstract, type over the instructions in the template box below. Fonts or abstract dimensions should not be changed or altered. [Display omitted] [ABSTRACT FROM AUTHOR]

Although rarely used in nature, fluorine has emerged as an important elemental ingredient in the design of proteins with altered folding, stability, oligomerization propensities, and bioactivity. Adding to the molecular modification toolbox, here we report the ability of privileged perfluorinated amphiphiles to noncovalently decorate proteins to alter their conformational plasticity and potentiate their dispersion into fluorous phases. Employing a complementary suite of biophysical, in-silico and in-vitro approaches, we establish structure-activity relationships defining these phenomena and investigate their impact on protein structural dynamics and intracellular trafficking. Notably, we show that the lead compound, perfluorononanoic acid, is 10 6 times more potent in inducing non-native protein secondary structure in select proteins than is the well-known helix inducer trifluoroethanol, and also significantly enhances the cellular uptake of complexed proteins. These findings could advance the rational design of fluorinated proteins, inform on potential modes of toxicity for perfluoroalkyl substances, and guide the development of fluorine-modified biologics with desirable functional properties for drug discovery and delivery applications., (© 2023 The Authors. ChemBioChem published by Wiley-VCH GmbH.)

The facile synthesis of 4-acetyl-2-hydroxy-2,5-dimethylfuran-3(2H)-one (4) was achieved by the Mn(OAc)3-mediated aerobic oxidation of 2,4-pentanedione or the direct reaction of Mn(acac)3 in AcOH-TFE at room temperature under a dried air stream. [ABSTRACT FROM AUTHOR]

Amyloid fibril formation is implicated in different human diseases. The transition between native α-helices and nonnative intermolecular β-sheets has been suggested to be a trigger of fibrillation in different conformational diseases. The FF domain of the URN1 splicing factor (URN1-FF) is a small all-α protein that populates a molten globule (MG) at low pH. Despite the fact that this conformation maintains most of the domain native secondary structure, it progressively converts into β-sheet enriched and highly ordered amyloid fibrils. In this study, we investigated if 2,2,2-trifluoroethanol (TFE) induced conformational changes that affect URN1-FF amyloid formation. Despite TFE having been shown to induce or increase the aggregation of both globular and disordered proteins at moderate concentrations, we demonstrate here that in the case of URN1-FF it reinforces its intrinsic α-helical structure, which competes the formation of aggregated assemblies. In addition, we show that TFE induces conformational diversity in URN1-FF fibrils, in such a way that the fibrils formed in the presence and absence of the cosolvent represent different polymorphs. It is suggested that the effect of TFE on both the soluble and aggregated states of URN1-FF depends on its ability to facilitate hydrogen bonding.

The facile synthesis of 4-acetyl-2-hydroxy-2,5-dimethylfuran-3(2H)-one (4) was achieved by the Mn(OAc)3-mediated aerobic oxidation of 2,4-pentanedione or the direct reaction of Mn(acac)3 in AcOH-TFE at room temperature under a dried air stream.