Dynamics of Ionic Liquid-Assisted Refolding of Denatured Cytochrome <i>c</i>: A Study of Preferential Interactions toward Renaturation

In vitro refolding of denatured protein and the influence of the alkyl chain on the refolding of a protein were tested using long chain imidazolium chloride salts, 1-methyl-3-octylimidazolium chloride [C₈mim]­[Cl], and 1-decyl-3-methylimidazolium chloride [C₁₀mim]­[Cl]. The horse heart cytochrome <i>c</i> (h-cyt <i>c</i>) was denatured by urea and guanidinium hydrochloride (GdnHCl), as well as by base-induced denaturation at pH 13, to provide a broad overview of the overall refolding behavior. The variation in the alkyl chain of the ionic liquids (ILs) showed a profound effect on the refolding of denatured h-cyt <i>c</i>. The ligand-induced refolding was correlated to understand the mechanism of the conformational stability of proteins in aqueous solutions of ILs. The results showed that the long chain ILs having the [C₈mim]⁺ and [C₁₀mim]⁺ cations promote the refolding of alkali-denatured h-cyt <i>c</i>. The IL having the [C₁₀mim]⁺ cation efficiently refolded the alkali-denatured h-cyt <i>c</i> with the formation of the MG state, whereas the IL having the [C₈mim]⁺ cation, which is known to be compatible for protein stability, shows slight refolding and forms a different transition state. The lifetime results show successful refolding of alkaline-denatured h-cyt <i>c</i> by both of the ILs, however, more refolding was observed in the case of [C₁₀mim]­[Cl], and this was correlated with the fast and medium lifetimes (τ₁ and τ₂) obtained, which show an increase accompanied by an increase in secondary structure. The hydrophobic interactions plays an important role in the refolding of chemically and alkali-denatured h-cyt <i>c</i> by long chain imidazolium ILs. The formation of the MG state by [C₁₀mim]­[Cl] was also confirmed, as some regular structure exists far below the CMC of IL. The overall results suggested that the [C₁₀mim]⁺ cation bound to the unfolded h-cyt <i>c</i> triggers its refolding by electrostatic and hydrophobic interactions that stabilize the MG state

Development of Cholinium-Based API Ionic Liquids with Enhanced Drug Solubility: Biological Evaluation and Interfacial Properties

We report an efficient sustainable two-step anion exchange synthetic procedure for the preparation of choline API ionic liquids (Cho-API-ILs) that contain active pharmaceutical ingredients (APIs) as anions combined with choline-based cations. We have evaluated the in vitro cytotoxicity for the synthesized compounds using three different cells lines, namely, HEK293 (normal kidney cell line), SW480, and HCT 116 (colon carcinoma cells). The solubility of APIs and Cho-API-ILs was evaluated in water/buffer solutions and was found higher for Cho-API-ILs. Further, we have investigated the antimicrobial potential of the pure APIs, ILs, and Cho-API-ILs against clinically relevant microorganisms, and the results demonstrated the promise of Cho-API-ILs as potent antimicrobial agents to treat bacterial infections. Moreover, the aggregation and adsorption properties of the Cho-API-ILs were observed by using a surface tension technique. The aggregation behavior of these Cho-API-ILs was further supported by conductivity and pyrene probe fluorescence. The thermodynamics of aggregation for Cho-API-ILs has been assessed from the temperature dependence of surface tension. The micellar size and their stability have been studied by dynamic light scattering, transmission electron microscopy, and zeta potential. Therefore, the duality in the nature of Cho-API-ILs has been explored with the upgradation of their physical, chemical, and biopharmaceutical properties, which enhance the opportunities for advances in pharmaceutical sciences

Effect of 1-methyl-3-octyleimmidazolium chloride on the stability and activity of lysozyme: a spectroscopic and molecular dynamics studies

<p>Herein, the binding of 1-methyl-3-octylimidazolium chloride [OMIM][Cl] ionic liquid with hen egg white lysozyme (HEWL) has been studied using fluorescence, time resolved fluorescence, UV–visible and circular dichroism (CD) spectroscopy, in combination with computational study. The fluorescence results revealed that [OMIM][Cl] quenches the fluorophore of HEWL through static quenching mechanism. The calculated thermodynamic parameters show that [OMIM][Cl] bind with HEWL through hydrophobic interactions. In addition, the negative value of Gibbs energy change (∆<i>G</i>) indicates that the binding process was spontaneous. Furthermore, UV–vis and CD results indicate that [OMIM][Cl] induce the conformational change in HEWL and increase its enzymatic activity. Additionally, molecular docking results showed that [OMIM][Cl] binds at the active site of HEWL where both the fluorophore residues (Trp108 and Trp62) and the catalytic residues (Glu35 and Asp52) reside. Molecular dynamic simulation results show the reduction of intra-molecular hydrogen bond of HEWL when it binds with [OMIM][Cl].</p

Mechanism and Dynamics of Long-Term Stability of Cytochrome <i>c</i> Conferred by Long-Chain Imidazolium Ionic Liquids at Low Concentration

Protein stability has been a concern for researchers for a long time as they are sensitive toward their environment. Mostly proteins during experiments require medium that keep them stable at room temperature (RT). Recent research utilizing ionic liquids (ILs) to stabilize protein has gained much importance. Although a few ILs have been claimed to suit this requirement, reported studies employ IL concentrations that might produce irreversible denaturation and aggregation. This study demonstrates the first report for long-term stabilization of horse heart cytochrome <i>c</i> (h-cyt <i>c</i>) by long-chain imidazolium ILs at far low concentration (1 mM) of IL when stored at RT. Long-chain imidazolium ILs until now were less familiar for their stabilizing nature toward protein. A significant increase in the helical content of h-cyt <i>c</i> (dissolved state) was observed with prolonged structural stability (secondary and tertiary) for about 6 months in aqueous solutions of 1-methyl-3-octyl imidazolium chloride [C₈mim]­[Cl] and 1-decyl-3-methylimidazolium chloride [C₁₀mim]­[Cl]. The in-depth mechanism discussed suggests interaction of ILs with amino acid residues of h-cyt <i>c</i>, which rigidifies the loop regions with reduced mobility; hence, prolonged stability is achieved. The study firmly advocates the use of long-chain imidazolium ILs as the potent inhibitor against denaturation during storage of h-cyt <i>c</i> at RT

DataSheet_1_The value of metabolic LncRNAs in predicting prognosis and immunotherapy efficacy of gastric cancer.xlsx

IntroductionAs a unique feature of malignant tumors, abnormal metabolism can regulate the immune microenvironment of tumors. However, the role of metabolic lncRNAs in predicting the prognosis and immunotherapy of gastric cancer (GC) has not been explored.MethodsWe downloaded the metabolism-related genes from the GSEA website and identified the metabolic lncRNAs. Co-expression analysis and Lasso Cox regression analysis were utilized to construct the risk model. To value the reliability and sensitivity of the model, Kaplan–Meier analysis and receiver operating characteristic curves were applied. The immune checkpoints, immune cell infiltration and tumor mutation burden of low- and high-risk groups were compared. Tumor Immune Dysfunction and Exclusion (TIDE) score was conducted to evaluate the response of GC patients to immunotherapy.ResultsTwenty-three metabolic lncRNAs related to the prognosis of GC were obtained. Three cluster patterns based on metabolic lncRNAs could distinguish GC patients with different overall survival time (OS) effectively (pDiscussionThe metabolic lncRNAs risk model can reliably and independently predict the prognosis of GC. The feature that simultaneously map the immune status of tumor microenvironment and TMB gives risk model great potential to serve as an indicator of immunotherapy.</p

DataSheet_3_The value of metabolic LncRNAs in predicting prognosis and immunotherapy efficacy of gastric cancer.docx

IntroductionAs a unique feature of malignant tumors, abnormal metabolism can regulate the immune microenvironment of tumors. However, the role of metabolic lncRNAs in predicting the prognosis and immunotherapy of gastric cancer (GC) has not been explored.MethodsWe downloaded the metabolism-related genes from the GSEA website and identified the metabolic lncRNAs. Co-expression analysis and Lasso Cox regression analysis were utilized to construct the risk model. To value the reliability and sensitivity of the model, Kaplan–Meier analysis and receiver operating characteristic curves were applied. The immune checkpoints, immune cell infiltration and tumor mutation burden of low- and high-risk groups were compared. Tumor Immune Dysfunction and Exclusion (TIDE) score was conducted to evaluate the response of GC patients to immunotherapy.ResultsTwenty-three metabolic lncRNAs related to the prognosis of GC were obtained. Three cluster patterns based on metabolic lncRNAs could distinguish GC patients with different overall survival time (OS) effectively (pDiscussionThe metabolic lncRNAs risk model can reliably and independently predict the prognosis of GC. The feature that simultaneously map the immune status of tumor microenvironment and TMB gives risk model great potential to serve as an indicator of immunotherapy.</p

Synthesis of gemini benzimidazolium surfactant and interaction of their micellar aggregates with antibacterial drug levofloxacin: A multi-technique approach

The cationic gemini 1,3-bis-(1-tetradecylbenzimidazolium) propane bromide (BG14) surfactant has been synthesized and the influence of the levofloxacin (Lvf), a potential antibacterial drug on the micellar properties of BG14 surfactant was observed. Hence, it would be exciting to calculate the state of micelle-formation for designing a system that would be helpful in pharmaceutical formulations. Thus, various techniques like tensiometry, cyclic voltammetry, conductivity, UV-visible, fluorescence, and time-resolved fluorescence were utilized to investigate the interaction between BG14 surfactant with Lvf. In addition, Rubingh’s model was used to evaluate various mixed micellar parameters like X1, Xideal, cmc*, β, and GE. FTIR study confirmed the existence of inter-molecular interactions among Lvf+BG14 over the studied concentration range. Lastly, this study can prove to be impactful in measuring and developing gemini-surfactant immobilized Lvf for improved biological action.</p

DataSheet_2_The value of metabolic LncRNAs in predicting prognosis and immunotherapy efficacy of gastric cancer.docx

IntroductionAs a unique feature of malignant tumors, abnormal metabolism can regulate the immune microenvironment of tumors. However, the role of metabolic lncRNAs in predicting the prognosis and immunotherapy of gastric cancer (GC) has not been explored.MethodsWe downloaded the metabolism-related genes from the GSEA website and identified the metabolic lncRNAs. Co-expression analysis and Lasso Cox regression analysis were utilized to construct the risk model. To value the reliability and sensitivity of the model, Kaplan–Meier analysis and receiver operating characteristic curves were applied. The immune checkpoints, immune cell infiltration and tumor mutation burden of low- and high-risk groups were compared. Tumor Immune Dysfunction and Exclusion (TIDE) score was conducted to evaluate the response of GC patients to immunotherapy.ResultsTwenty-three metabolic lncRNAs related to the prognosis of GC were obtained. Three cluster patterns based on metabolic lncRNAs could distinguish GC patients with different overall survival time (OS) effectively (pDiscussionThe metabolic lncRNAs risk model can reliably and independently predict the prognosis of GC. The feature that simultaneously map the immune status of tumor microenvironment and TMB gives risk model great potential to serve as an indicator of immunotherapy.</p

Ionic Liquid Influenced Synergistic Interaction between Amitriptyline Hydrochloride and Cetyl­trimethyl­ammonium Bromide

The mixed micellization behavior of amitriptyline hydrochloride (AMT) with cetyl­trimethyl­ammonium bromide (CTAB) has been studied at different mole fractions in the presence of imidazolium based ionic liquid 1-butyl-3-methyl imidazolium hydrochloride (Bmim·Cl), by using electrical conductivity at different temperatures from 298 to 318 K. A shift in the <i>T</i>_max value (i.e., the temperature at which the cmc value is maximized) has been observed with the rise in CTAB mole fraction. Synergistic interaction is explained by the deviations in critical micelle concentration (cmc) from an ideal critical micelle concentration (cmc*) and micellar mole fraction (<i>X</i>^m) from ideal micellar mole fraction (<i>X</i>^ideal) values. The calculated thermodynamic parameters (viz., the standard Gibbs energy change, Δ<i>G</i>_m^°, the standard enthalpy change, Δ<i>H</i>_m^°, and the standard entropy change, Δ<i>S</i>_m^°) suggest the dehydration of hydrophobic part of the drug at higher temperatures in the case of AMT as well as in CTAB-AMT binary systems in the presence of Bmim·Cl, whereas the temperature at which dehydration occurs changes with the rise in the mole fraction of CTAB

Enthalpy-driven interaction between dihydropyrimidine compound and bovine serum albumin: a spectroscopic and computational approach

Enthalpy-driven interaction between dihydropyrimidine compound and bovine serum albumin: a spectroscopic and computational approac