Jitendra Kumar Maurya

Spectroscopic and docking studies on the interaction between pyrrolidinium based ionic liquid and bovine serum albumin

The interaction of synthesized ionic liquid, 1-butyl-1-methyl-2-oxopyrrolidinium bromide (BMOP) and bovine serum albumin (BSA) was investigated using UV-Vis, FT-IR, steady state and time resolved fluorescence measurements and docking studies. Steady state spectra revealed that BMOP strongly quenched the intrinsic fluorescence of BSA through dynamic quenching mechanism. The corresponding thermodynamic parameters; Gibbs free energy change (ΔG), entropy change (ΔS) and enthalpy change (ΔH) showed that the binding process was spontaneous and entropy driven. It is also indicated that hydrophobic forces play a key role in the binding of BMOP to BSA. The synchronous fluorescence spectroscopy reveals that the conformation of BSA changed in the presence of BMOP. The shift in amide I band of FT-IR spectrum of BSA suggested unfolding of the protein secondary structure upon the addition of BMOP. In addition, the molecular modeling study of BSA-BMOP system shows that BMOP binds with BSA at the interface between two sub domains IIA and IIIA, which is located just above the entrance of the binding pocket of IIA through hydrophobic and hydrogen bond interactions in which hydrophobic interaction are dominated.

Probing HSA-ionic liquid interactions by spectroscopic and molecular docking methods

Herein, we report the interaction of synthesized pyrrolidinium based ionic liquid, N-butyl-N-methyl-2-oxopyrrolidinium bromide (BMOP) with human serum albumin (HSA). The BMOP was characterized by using (1)H NMR, (13)C NMR and FT-IR techniques. The critical micelle concentration (cmc) of BMOP was confirmed by surface tension, conductivity and contact angle measurements. The interactions between HSA and BMOP were studied by steady-state and time-resolved fluorescence, UV-visible, FT-IR spectroscopic and molecular docking methods. The steady-state fluorescence spectra showed that BMOP quenched the fluorescence of HSA through combined quenching mechanism. Corresponding thermodynamic parameters viz. Gibbs free energy change (ΔG), entropy change (ΔS) and enthalpy change (ΔH) illustrated that the binding process was spontaneous and entropy driven. It is also suggested that hydrophobic forces play a key role in the binding of BMOP to HSA. In addition, the pyrene probe analysis again suggests the involvement of hydrophobic interaction in HSA-BMOP complex formation. Surface tension profile showed that the cmc value of BMOP in the presence of HSA is higher than the cmc value of pure BMOP. The FT-IR results show a conformational change in the secondary structure of HSA upon the addition of BMOP. The molecular docking result indicated that BMOP binds with HSA at hydrophobic pocket domain IIA with hydrophobic and hydrogen bond interactions in which hydrophobic interactions are dominating.

Molecular investigation of the interaction between ionic liquid type gemini surfactant and lysozyme: A spectroscopic and computational approach

Herein, we are reporting the interaction of ionic liquid type gemini surfactant, 1,4‐bis(3‐dodecylimidazolium‐1‐yl) butane bromide ([C12−4‐C12im]Br2) with lysozyme by using Steady state fluorescence, UV‐visible, Time resolved fluorescence, Fourier transform‐infrared (FT‐IR) spectroscopy techniques in combination with molecular modeling and docking method. The steady state fluorescence spectra suggested that the fluorescence of lysozyme was quenched by [C12−4‐C12im]Br2 through static quenching mechanism as confirmed by time resolved fluorescence spectroscopy. The binding constant for lysozyme‐[C12−4‐C12im]Br2 interaction have been measured by UV‐visible spectroscopy and found to be 2.541 × 105M−1. The FT‐IR results show conformational changes in the secondary structure of lysozyme by the addition of [C12−4‐C12im]Br2. Moreover, the molecular docking study suggested that hydrogen bonding and hydrophobic interactions play a key role in the protein‐surfactant binding. Additionally, the molecular dynamic simulation results revealed that the lysozyme‐[C12−4‐C12im]Br2 complex reaches an equilibrium state at around 3 ns.

Spectroscopic and molecular modelling analysis of the interaction between ethane-1,2-diyl bis(N,N-dimethyl-N-hexadecylammoniumacetoxy)dichloride and bovine serum albumin.

Several spectroscopic approaches namely fluorescence, time-resolved fluorescence, UV-visible, and Fourier transform infra-red (FT-IR) spectroscopy were employed to examine the interaction between ethane-1,2-diyl bis(N,N-dimethyl-N-hexadecylammoniumacetoxy)dichloride (16-E2-16) and bovine serum albumin (BSA). Fluorescence studies revealed that 16-E2-16 quenched the BSA fluorescence through a static quenching mechanism, which was further confirmed by UV-visible and time-resolved fluorescence spectroscopy. In addition, the binding constant and the number of binding sites were also calculated. The thermodynamic parameters at different temperatures (298 K, 303 K, 308 K and 313 K) indicated that 16-E2-16 binding to BSA is entropy driven and that the major driving forces are electrostatic interactions. Decrease of the α-helix from 53.90 to 46.20% with an increase in random structure from 22.56 to 30.61% were also observed by FT-IR. Furthermore, the molecular docking results revealed that 16-E2-16 binds predominantly by electrostatic and hydrophobic forces to some residues in the BSA sub-domains IIA and IIIA.

A spectroscopic and molecular dynamic approach on the interaction between ionic liquid type gemini surfactant and human serum albumin.

The interactions of imidazolium bashed ionic liquid-type cationic gemini surfactant ([C12-4-C12im]Br2) with HSA were studied by fluorescence, time-resolved fluorescence, UV-visible, circular dichroism, molecular docking and molecular dynamic simulation methods. The results showed that the [C12-4-C12im]Br2 quenched the fluorescence of HSA through dynamic quenching mechanism as confirmed by time-resolved spectroscopy. The Stern–Volmer quenching constant (Ksv) and relevant thermodynamic parameters such as enthalpy change (ΔH), Gibbs free energy change (ΔG) and entropy change (ΔS) for interaction system were calculated at different temperatures. The results revealed that hydrophobic forces played a major role in the interactions process. The results of synchronous fluorescence, UV-visible and CD spectra demonstrated that the binding of [C12-4-C12im]Br2 with HSA induces conformational changes in HSA. Inquisitively, the molecular dynamics study contribute towards understanding the effect of binding of [C12-4-C12im]Br2 on HSA to interpret the conformational change in HSA upon binding in aqueous solution. Moreover, the molecular modelling results show the possible binding sites in the interaction system.

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

Diazines represent an important class of heterocyclic compounds, which are known to exhibit a wide spectrum of biological activities, and the majority of these versatile compounds are the backbone ...

Hydrogen bonding-assisted interaction between amitriptyline hydrochloride and hemoglobin: spectroscopic and molecular dynamics studies

Herein, we have explored the interaction between amitriptyline hydrochloride (AMT) and hemoglobin (Hb), using steady-state and time-resolved fluorescence spectroscopy, UV–visible spectroscopy, and circular dichroism spectroscopy, in combination with molecular docking and molecular dynamic (MD) simulation methods. The steady-state fluorescence reveals the static quenching mechanism in the interaction system, which was further confirmed by UV–visible and time-resolved fluorescence spectroscopy. The binding constant, number of binding sites, and thermodynamic parameters viz. ΔG, ΔH, ΔS are also considered; result confirms that the binding of the AMT with Hb is a spontaneous process, involving hydrogen bonding and van der Waals interactions with a single binding site, as also confirmed by molecular docking study. Synchronous fluorescence, CD data, and MD simulation results contribute toward understanding the effect of AMT on Hb to interpret the conformational change in Hb upon binding in aqueous solution.

Effect of aromatic amino acids on the surface properties of 1-dodecyl-3-(4-(3-dodecylimidazolidin-1-yl)butyl)imidazolidine bromide gemini surfactant

ABSTRACT Herein, we have studied the micellization of imidazolium-based ionic liquid type gemini surfactant ([C12-4-C12im]Br2) in the absence and presence of aromatic amino acids by conductivity and surface tension measurements at different temperatures (i.e., 298, 308, and 318 K). Various interfacial parameters, that is, Gibbs surface excess (Γmax), minimum head group area at air/water interface (Amin), and thermodynamic parameters, that is, free energy of micellization/adsorption (), the standard entropy of micellization/adsorption (), and the standard enthalpy of micellization/adsorption () were evaluated for all the systems. The standard entropy of adsorption () was found higher than the standard entropy of micellization () for all the systems at all temperatures. The results also showed that the micellization of [C12-4-C12im]Br2 depends on the nature of amino acids as well as temperature. The CMC of [C12-4-C12im]Br2 in the absence and presence of amino acids at different temperature decreases with the increase of temperature. GRAPHICAL ABSTRACT

Interaction of promethazine and adiphenine to human hemoglobin: A comparative spectroscopic and computational analysis

The binding nature of amphiphilic drugs viz. promethazine hydrochloride (PMT) and adiphenine hydrochloride (ADP), with human hemoglobin (Hb) was unraveled by fluorescence, absorbance, time resolved fluorescence, fluorescence resonance energy transfer (FRET) and circular dichroism (CD) spectral techniques in combination with molecular docking and molecular dynamic simulation methods. The steady state fluorescence spectra indicated that both PMT and ADP quenches the fluorescence of Hb through static quenching mechanism which was further confirmed by time resolved fluorescence spectra. The UV-Vis spectroscopy suggested ground state complex formation. The activation energy (Ea) was observed more in the case of Hb-ADP than Hb-PMT interaction system. The FRET result indicates the high probability of energy transfer from β Trp37 residue of Hb to the PMT (r=2.02nm) and ADP (r=2.33nm). The thermodynamic data reveal that binding of PMT with Hb are exothermic in nature involving hydrogen bonding and van der Waal interaction whereas in the case of ADP hydrophobic forces play the major role and binding process is endothermic in nature. The CD results show that both PMT and ADP, induced secondary structural changes of Hb and unfold the protein by losing a large helical content while the effect is more pronounced with ADP. Additionally, we also utilized computational approaches for deep insight into the binding of these drugs with Hb and the results are well matched with our experimental results.