A surprisingly simple three-state generic process for reversible protein denaturation by trifluoroethanol

Hossain, Mujahid; Sahari, Noorul Huda; Bhuyan, Abani K.

doi:10.1016/j.bpc.2022.106895

Cited by 3 publications

(3 citation statements)

References 96 publications

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“…At TFE concentrations >30%, the addition of TFE appears to increase the helicity of Nsp1 FL and Nsp1 ΔCTD proteins. Consistent with our observations, a previous study revealed that at low TFE concentrations, proteins can denature due to low-affinity hydrophobic interactions . Overall, these results suggest that additional regions within Nsp1 FL and ΔCTD have a propensity to form helices.…”

Section: Resultsmentioning

confidence: 99%

Biochemical and HDX Mass Spectral Characterization of the SARS-CoV-2 Nsp1 Protein

et al. 2023

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A major challenge in defining the pathophysiology of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is to better understand virally encoded multifunctional proteins and their interactions with host factors. Among the many proteins encoded by the positive-sense, single-stranded RNA genome, nonstructural protein 1 (Nsp1) stands out due to its impact on several stages of the viral replication cycle. Nsp1 is the major virulence factor that inhibits mRNA translation. Nsp1 also promotes host mRNA cleavage to modulate host and viral protein expression and to suppress host immune functions. To better define how this multifunctional protein can facilitate distinct functions, we characterize SARS-CoV-2 Nsp1 by using a combination of biophysical techniques, including light scattering, circular dichroism, hydrogen/deuterium exchange mass spectrometry (HDX-MS), and temperature-dependent HDX-MS. Our results reveal that the SARS-CoV-2 Nsp1 N-and C-terminus are unstructured in solution, and in the absence of other proteins, the C-terminus has an increased propensity to adopt a helical conformation. In addition, our data indicate that a short helix exists near the C-terminus and adjoins the region that binds the ribosome. Together, these findings provide insights into the dynamic nature of Nsp1 that impacts its functions during infection. Furthermore, our results will inform efforts to understand SARS-CoV-2 infection and antiviral development.

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Section: Resultsmentioning

confidence: 99%

Biochemical and HDX Mass Spectral Characterization of the SARS-CoV-2 Nsp1 Protein

et al. 2023

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“…19 The present study has opted to use 2,2,2trifluoroethanol (TFE), a fluorinated alcohol, 20,21 due to its great demand as a cosolvent in molecular biology, particularly during the denaturation process of proteins. 22,23 More importantly, TFE has been extensively reported in the literature in elucidation of the secondary structures of biological macromolecules, including polypeptides and proteins. 24,25 The presence of electron-withdrawing trifluoromethyl (CF 3 ) group in TFE imparts unique qualities as a solvent compared to other conventional alcohols.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, alcohols possess a dual character of serving as either cosurfactants or cosolvents as a motif to modify the critical micelle concentration (CMC) in the self-assembly of amphiphilic systems . The present study has opted to use 2,2,2-trifluoroethanol (TFE), a fluorinated alcohol, , due to its great demand as a cosolvent in molecular biology, particularly during the denaturation process of proteins. , More importantly, TFE has been extensively reported in the literature in elucidation of the secondary structures of biological macromolecules, including polypeptides and proteins. , The presence of electron-withdrawing trifluoromethyl (CF 3 ) group in TFE imparts unique qualities as a solvent compared to other conventional alcohols. − TFE has the advantage of being highly soluble in water, irrespective of having a hydrophobic −CF 3 terminal. Fatima et al has performed a comparative analysis to investigate the effects of TFE and ethanol solvents on the thermal stability of an ionic liquid 1-ethyl-3-methylimidazolium dicyanamide ([EMIM][DCA]) in a TFE/ethanol binary mixture.…”

Section: Introductionmentioning

confidence: 99%

Comparative Study of the Aggregation Behavior of Some Ionic Surfactants with Nonionic Triton X-114 in Water and a Water/2,2,2-Trifluoroethanol Mixture

Banik,

Mondal,

Sardar

et al. 2024

Ind. Eng. Chem. Res.

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The influence of 2,2,2-trifluoroethanol (TFE) on the micellar properties of ionic surfactants hexadecyltrimethylammonium bromide (CTAB), hexadecyltrimethylammonium ptoluenesulfonate (CTAT), sodium dodecyl sulfate (SDS), Nlauroylsarcosine sodium salt (SDDS), and nonionic surfactant Triton X-114 (TX-114) in aqueous solutions was studied using tensiometry, electrical conductivity, fluorimetry, time-resolved fluorescence, and microcalorimetry. With increasing concentrations of TFE, the micellar charge densities of the ionic head groups decrease, causing a decrease in the critical micelle concentration (CMC) of ionic-surfactant solutions (SDS, SDDS, CTAB, and CTAT) in micellar solutions. However, for nonionic surfactant TX-114, the polar headgroup undergoes some conformational changes causing an increase in the value of CMC. Time-resolved fluorescence decay measurements were done to get evidence of penetration of TFE molecules into the stern layer of the micelle. The micellar aggregation number declines with increasing concentration of solvent, indicating a higher concentration of mixed solvent reducing the number of monomers needed for micellization for ionic surfactants, whereas for nonionic TX-114, it indicates some structural changes of the molecule forming the micelle in the presence of TFE.

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A three-state mechanism for trifluoroethanol denaturation of an intrinsically disordered protein (IDP)

Hossain,

Huda,

Bhuyan

2023

The Journal of Biochemistry

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Summary Relating the amino acid composition and sequence to chain folding and binding preferences of intrinsically disordered proteins (IDPs) has emerged as a huge challenge. While globular proteins have respective 3D structures that are unique to their individual functions, IDPs violate this structure-function paradigm because rather than having a well-defined structure an ensemble of rapidly interconverting disordered structures characterize an IDP. This work measures 2,2,2-trifluoroethanol (TFE)-induced equilibrium transitions of an IDP called AtPP16-1 (Arabidopsis thaliana phloem protein type 16-1) by using fluorescence, circular dichroism, infrared, and NMR methods at pH 4, 298 K. Low TFE reversibly removes the tertiary structure to produce an ensemble of obligate intermediate ($\mathrm{I}$) retaining the native-state ($\mathrm{N}$) secondary structure. The intermediate $\mathrm{I}$ is preceded by a non-obligate tryptophan-specific intermediate ${\mathrm{I}}_{\mathrm{w}}$ whose population is detectable for AtPP16-1 specifically. Accumulation of such non-obligate intermediates is discriminated according to the sequence composition of the protein. In all cases, however, a tertiary structure-unfolded general obligate intermediate $\mathrm{I}$ is indispensable. The $\mathrm{I}$ensemble has higher helical propensity conducive to the acquisition of an exceedingly large level of α-helices by a reversible denaturation transition of $\mathrm{I}$ to the denatured state $\mathrm{D}$ as the TFE level is increased. Strikingly, it is the same $\mathrm{N}\rightleftharpoons \mathrm{I}\rightleftharpoons \mathrm{D}$ scheme typifying the TFE transitions of globular proteins. The high-energy state $\mathrm{I}$ characterized by increased helical propensity is called a universal intermediate encountered in both genera of globular and disordered proteins. Neither $\mathrm{I}$ nor $\mathrm{D}$ strictly show molten globule (MG)-like properties, dismissing the belief that TFE promotes MGs.

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A surprisingly simple three-state generic process for reversible protein denaturation by trifluoroethanol

Cited by 3 publications

References 96 publications

Biochemical and HDX Mass Spectral Characterization of the SARS-CoV-2 Nsp1 Protein

Biochemical and HDX Mass Spectral Characterization of the SARS-CoV-2 Nsp1 Protein

Comparative Study of the Aggregation Behavior of Some Ionic Surfactants with Nonionic Triton X-114 in Water and a Water/2,2,2-Trifluoroethanol Mixture

A three-state mechanism for trifluoroethanol denaturation of an intrinsically disordered protein (IDP)

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