Secondary Structure Of Lysozyme Research Articles

Synthesis and Self-Assembly of Hyperbranched Multiarm Copolymer Lysozyme Conjugates Based on Light-Induced Metal-Free Atrp

In recent years, the coupling of structurally and functionally controllable polymers with biologically active protein materials to obtain polymer-protein conjugates with excellent overall properties and good biocompatibility has been important research in the field of polymers. In this study, the hyperbranched polymer hP(DEGMA-co-OEGMA) was first prepared by combining self-condensation vinyl polymerization (SCVP) with photo-induced metal-free atom transfer radical polymerization (ATRP), with 2-(2-bromo-2-methylpropanoyloxy) ethyl methacrylate (BMA) as inimer, and Di (ethylene glycol) methyl ether methacrylate (DEGMA) and (oligoethylene glycol) methacrylate (OEGMA, Mn = 300) as the copolymer monomer. Then, hP(DEGMA-co-OEGMA) was used as a macroinitiator to continue the polymerization of a segment of pyridyl disulfide ethyl methacrylate (DSMA) monomer to obtain the hyperbranched multiarm copolymers hP(DEGMA-co-OEGMA)-star-PDSMA. Finally, the lysozyme with sulfhydryl groups was affixed to the hyperbranched multiarm copolymers by the exchange reaction between sulfhydryl groups and disulfide bonds to obtain the copolymer protein conjugates hP(DEGMA-co-OEGMA)-star-PLZ. Three hyperbranched multiarm copolymers with relatively close molecular weights but different degrees of branching were prepared, and all three conjugates could self-assemble to form nanoscale vesicle assemblies with narrow dispersion. The biological activity and secondary structure of lysozyme on the assemblies remained essentially unchanged.

Investigations on the binding properties of hydroxylated polybrominated diphenyl ethers with lysozyme using the multispectral techniques and molecular modeling

As a kind of phenolic chemical with endocrine disrupting potency, hydroxylated polybrominated diphenyl ethers (OH-PBDEs) cause a latent threat to human health from their residue in the environment. Their binding efficiency with lysozyme (LYSO) was studied by molecular simulation combined with fluorescence, UV–vis absorption and circular dichroism (CD), so as to assess their toxicity at the molecular level. Molecular docking data indicate that van der Waals force is the principal interaction force between OH-PBDEs and LYSO. The binding site for 5′-OH-BDE-25 in LYSO is ascertained as the active site, which interaction with the TRP63 and TRP108 residues of LYSO to take shape a strong face-to-face stacked rank (F-shaped). Both 4′-OH-BDE-99 and 3′-OH-BDE-154 display a certain degree of deviation from the active site. Nevertheless, their F-shaped interaction with TRP63 conduce to bind LYSO and stabilize the docking conformation. Combined with dynamics simulation and spectral analysis, the secondary structure of LYSO can be induced by the three kinds of OH-PBDEs. CD spectrum shows that the combination of LYSO and OH-PBDEs will make α- Helix content increased. The combination of OH-PBDEs and LYSO touch upon a static quenching mechanism as a result of steady state fluorescence. The energy decomposition analysis exhibited that LYSO-OH-PBDEs binding site was stable by van der Waals and hydrophobic interaction. As enzyme activity experiments demonstrate that OH-PBDEs can inhibit the activity of LYSO, which is helpful to clarify the molecular toxicity mechanism of OH-PBDEs.

Ultrasound-Assisted High-Voltage Cold Atmospheric Plasma Treatment on the Inactivation and Structure of Lysozyme: Effect of Treatment Voltage

Emerging nonthermal processing techniques are gaining much attention due to their numerous advantages over traditional methods. Thus, in this study, high-voltage cold atmospheric plasma (HV-CAP) was employed separately and synergetically with ultrasound on lysozyme to investigate its activity and structure. The HV-CAP was operated at 120, 140, and 160 kV for 3 min at a frequency of 120 Hz. A significant difference was observed between the untreated and both treatments in lysozyme activity, with a more pronounced result in the ultrasound-assisted HV-CAP treatment. Both treatments resulted in the modification of the tertiary structure of the lysozyme as lipid oxidation, carbonyl content, UV spectra, intrinsic fluorescence, hydrophobicity, and sulphhydryl groups increased with increased voltage. Particle size distribution of lysozyme shows that noncovalent interactions affected the tertiary structure. The effects of both treatments on the secondary structure of lysozyme were demonstrated by CD and relative molar ellipticity. The results indicated that plasma-generated reactive species and ultrasound-induced cavitation influenced the unfolding of tertiary and secondary structures of the lysozyme. The CD spectra postulated that lysozyme inactivation was closely linked to the α-helix and β-sheet components of the secondary structure. This study presents an original novel knowledge on the modification of activity and structure of lysozyme subjected to ultrasound-assisted HV-CAP treatment that has been missing from the literature.Graphical abstract

Interaction of Carrier Protein with Potential Metallic Drug Candidate N-Glycoside 'GATPT': Validation by Multi-Spectroscopic and Molecular Docking Approaches.

Lysozyme is often used as a model protein to study interaction with drug molecules and to understand biological processes which help in illuminating the therapeutic effectiveness of the drug. In the present work, in vitro interaction studies of 1-{(2-hydroxyethyl)amino}-2-amino-1,2-dideoxy-d-glucose triphenyl tin (IV) (GATPT) complex with lysozyme were carried out by employing various biophysical methods such as absorption, fluorescence, and circular dichroism (CD) spectroscopies. The experimental results revealed efficient binding affinity of GATPT with lysozyme with intrinsic binding (Kb) and binding constant (K) values in the order of 105 M−1. The number of binding sites and thermodynamic parameters ΔG, ΔH, and ΔS at four different temperatures were also calculated and the interaction of GATPT with lysozyme was found to be enthalpy and entropy driven. The CD spectra revealed alterations in the population of α–helical content within the secondary structure of lysozyme in presence of GATPT complex. The morphological analysis of the complex with lysozyme and lysozyme-DNA condensates was carried out by employing confocal and SEM studies. Furthermore, the molecular docking studies confirmed the interaction of GATPT within the larger hydrophobic pocket of the lysozyme via several non-covalent interactions.

The Effect of Luteolin and Luteoloside on the Secondary Structure of Lysozyme

The changes of lysozyme conformation in the absence and presence of luteolin and luteoloside were investigated by spectral analysis including fluorescence, UV, CD, Raman, and ATR-FTIR, and the biological activity of lysozyme was investigated by lysozyme assay kit. The results showed that the microenvironment hydrophobicity of lysozyme increased and peptide extension decreased with the addition of luteolin or luteoloside. The α-helix of lysozyme might be influenced by luteolin or luteoloside, and its relative content had a significant difference after adding luteolin or luteoloside by the ATR-FTIR method, which was reconfirmed by CD and Raman spectra. The lysozyme activity changed obviously after adding luteolin or luteoloside. All of the conclusions above indicated the active site of lysozyme in the α-helix might be influenced by luteolin and luteoloside.

Lysozyme-dalargin self-organization at the aqueous-air and liquid-liquid interfaces

An experimental study of protein-peptide binding was performed by means of radiochemical and spectroscopic methods. Lysozyme and dalargin were chosen due to their biological and physiological importance. By means of tensiometry and radiochemical assays, it was found that dalargin possesses rather high surface activity at the aqueous-air and aqueous-p-xylene interfaces to be substituted by protein. Dalargin forms a hydrophobic complex with lysozyme in which the secondary structure of lysozyme is preserved. When lysozyme forms a mixed adsorption layer with dalargin at the aqueous-air surface, the peptide prevents protein from concentrating in the subsurface monolayer. In the presence of p-xylene protein in the interface, reorganization occurs quickly, so there is no lag in the interfacial tension time dependence. The interfacial tension in this case is controlled by protein and/or protein-peptide complexes. An increase in the enzymatic activity of lysozyme in the presence of dalargin was confirmed by a docking model that suggests the formation of hydrogen bonds between dalargin and amino acid residues in the active site.

Dynamic interaction between lysozyme and ceftazidime: Experimental and molecular simulation approaches

The interaction of an important antibiotic drug, ceftazidime, with an imperative globular protein, lysozyme (which also possesses antibacterial properties), was studied. The formation of a complex between ceftazidime and lysozyme was verified by ultraviolet–visible (UV–Vis) spectroscopy. Intrinsic fluorescence spectroscopy (FS) was primarily employed to obtain information about the binding mechanism. The fluorescence data were corrected for the inner filter effect (IFE) before the analysis because of the strong absorption of ceftazidime at the excitation wavelength and the emission range of lysozyme. The apparent fluorescence quenching parameters, which were obtained after the IFE correction, exhibited the weak affinity between lysozyme and ceftazidime. The interaction was due to the dynamic quenching with a binding ratio of 1:1. Ceftazidime exerted small effect on the secondary structure of lysozyme. The binding site of ceftazidime in lysozyme was determined by molecular docking. The large hydrophobic pocket of lysozyme was the most preferred binding site for ceftazidime. The interaction was, primarily, reinforced by hydrophobic forces and hydrogen bonding with a small participation of electrostatic forces. Molecular dynamics (MD) simulations were also performed to theoretically understand the behavior of the drug–protein complex. The stability of lysozyme changed slightly in the presence of ceftazidime. The pattern of the radius of gyration (Rg) in the absence and presence of ceftazidime also exhibited a slight change. There was a slight decrease in the residual fluctuation of residues 50–90, whereas a significant increase was observed in the residual fluctuations of residues 100–120. In the 100 ns simulation of the formation of lysozyme and ceftazidime, the disruption of hydrogen bonding occurred with the probability of forming three to six hydrogen bonds during most of the time evolutions of the simulation. The density-functional theory (DFT) calculations indicated that the stability of ceftazidime decreased after binding with lysozyme.

Lysozyme conformational changes with ionic liquids: Spectroscopic, small angle x-ray scattering and crystallographic study

Solvents that support protein functionality are important for biochemical applications, and new solvents are required. Here we employ FTIR and fluorescence spectroscopies, small angle X-ray scattering (SAXS) and X-ray crystallography to understand conformational changes of lysozyme with ionic liquids (ILs) added. Spectroscopic techniques identified that the secondary structure of lysozyme was maintained at the lower IL concentrations of 1 and 5 mol%, though the Tryptophan environment was significantly altered with nitrate-based ILs present. SAXS experiments indicated that the radius of gyration of lysozyme increased with 1 mol% IL present, and then decreased with increasing IL concentrations. The tertiary structure, particularly the loop regions, changed as a function of IL concentration, and this depended on the IL type. The crystallographic structure of lysozyme with the IL of ethylammonium nitrate present confirmed the loop region was extended, and identified three specific binding sites with nitrate ions, and that the positively charged areas were IL sensitive regions. This work provides a detailed understanding of lysozyme conformational changes in the presence of ILs. This approach can be extended to other functionally-important proteins.

Mechanism of lysozyme adsorption onto gold surface determined by quartz crystal microbalance and surface plasmon resonance

In this study, the physicochemical characterization of lysozyme adsorbed on gold was investigated. Through the use of MP-SPR it was possible to establish that the orientation of molecules changes from side-on to between or end-on with increasing surface coverage. The data confirms that the process of adsorption is driven primarily by electrostatic interactions but also by hydrophobic forces. MP-SPR data was compared with the Random Sequential Adsorption model for a molecule with an ellipsoidal shape. Contact angle measurements showed that higher surface coverage also translates in more hydrophilic properties of obtained lysozyme layer. Comparison of CD and PM-IRRAS spectra in solution and adsorbed state respectively showed changes in the secondary structures of lysozyme. These changes are dependent on pH, but fundamentally they go in the direction of the increase of β-turn/random content with a simultaneous decrease in β-sheet fraction, which suggests that aggregation is not occurring. The combination of MP-SPR and QCM-D measurements allowed the estimation of the number of water molecules associated with the lysozymes films. It has been observed that hydration decreases from 70% in pH = 4 to 30% in pH = 11. This data indicates that hydration is driven mainly by the degree of protonation of lysozyme molecules.

Spectroscopic and Molecular Docking Investigation on the Noncovalent Interaction of Lysozyme with Saffron Constituent "Safranal".

Owing to the various beneficial properties of the popular spice saffron, the interaction of safranal, a secondary metabolite of the former, with hen egg white lysozyme was investigated. The formation of a complex was evidenced by UV–visible spectroscopy. Fluorescence quenching experiments were also performed to understand the binding mechanism and to evaluate the forces involved in binding. The strong absorption of safranal in the range of excitation and emission wavelengths of lysozyme fluorescence required the correction of the inner filter effect for fluorescence spectra to obtain the apparent extent of binding. There was a considerable difference between the observed spectra and corrected spectra, and a similar observation was found in the case of synchronous fluorescence spectra. From the analysis of quenching data, it was found that the mechanism involved in quenching was static with 1:1 binding between them. The interaction was found to be driven, mainly, by hydrophobic forces and hydrogen bonding. Safranal had negligible impact on the secondary structure of lysozyme. The interaction was also studied by molecular docking, and the results were in good agreement with the results obtained experimentally. The binding site of safranal was in the big hydrophobic cavity of lysozyme. The amino acids involved in the interaction were Asp52, Ile58, Gln57, Asn59, Trp62, Trp63, Trp108, Ile98, Asp101, and Ala107.

Binding Interaction of Juglone with Lysozyme: Spectroscopic Studies Aided by In Silico Calculations

Binding interactions between the drug Juglone (JUG) and Lysozyme (LYZ) have been explored in details from spectroscopic studies aided by in silico calculations. UV–Vis, steady state and time resolved fluorescence spectroscopic studies indicate the formation of LYZ–JUG complex in the ground state. Quenching of corrected fluorescence spectra of LYZ in presence of JUG at varied concentrations in different temperature range have been estimated from Stern–Volmer (SV) plots. Time resolved fluorescence spectroscopic studies confirm the mechanism of quenching to be of static type. Binding constant associated with the LYZ–JUG complex has been estimated from Scatchard plot. The number of binding sites, thermodynamic parameters and the modes of interaction are also estimated. Synchronous fluorescence spectra monitored at two discrete wavelength windows confirm the prominent role of Tryptophan residues towards quenching of fluorescence in LYZ. The circular dichroism (CD) spectra signify alterations in the population of α–helical content within the secondary structure of LYZ in presence of JUG molecules. REES of LYZ in the presence of JUG further signify definite impact of the drug JUG molecule on the Trp residues of the protein. The experimental observations are supported by in silico molecular docking and molecular dynamics simulations.

Preparation of hierarchically mesoporous bioactive glass and immobilization of lysozyme

Hierarchically mesoporous bioactive glass (HMBG) was prepared using pine pollen as the biological template for lysozyme immobilization via intermolecular interactions. Effects of the initial concentration of lysozyme, pH, stirring speed (rpm), and temperature on lysozyme adsorption were investigated. The results showed that HMBG could immobilize lysozyme efficiently, and a maximum adsorption capacity of 648 ± 5.1 mg g−1 was achieved at the optimum immobilization conditions. Moreover, it was found that the adsorption process fit well with the Langmuir isothermal model. Morphology and pore structure of prepared HMBG were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-Ray diffraction (XRD), and nitrogen adsorption–desorption measurements. Lysozyme immobilization was verified by Fourier transform infrared (FTIR) spectroscopy. In addition, no change in the secondary structure of lysozyme during the adsorption/desorption process was demonstrated by UV–visible spectroscopy (UV–Vis), molecular fluorescence spectrometry (MFS), and circular dichroism (CD) spectroscopy. Higher stability and better reusability of lysozyme–HMBG than those of alternatives were also shown.

The study on interactions between levofloxacin and model proteins by using multi-spectroscopic and molecular docking methods

The interactions of levofloxacin (LEV) with lysozyme (LYZ), trypsin and bovine hemoglobin (BHb) were investigated, respectively, by using multi-spectral techniques and molecular docking in vitro. Fluorescence studies showed that LEV quenched LYZ/trypsin fluorescence in a combined quenching ways and BHb fluorescence in a static quenching with binding constants of .14, .51 and .20 × 105 L mol−1 at 298 K, respectively. The thermodynamic parameters demonstrated that hydrophobic forces, hydrogen bonds, and van der Waals forces played the major role in the binding process. The binding distances between LEV and the inner tryptophan residues of LYZ, trypsin, and BHb were calculated to be 4.04, 3.38, and 4.52 nm, respectively. Furthermore, the results of circular dichroism spectra (CD), UV–vis, and three-dimensional fluorescence spectra indicated that the secondary structures of LYZ, trypsin, and BHb were partially changed by LEV with the α-helix percentage of LYZ-LEV system increased while that of BHb-LEV system was decreased, the β-sheet percentage of trypsin-LEV system increased from 41.3 to 42.9%. UV–vis spectral results showed that the binding interactions could cause conformational and some micro-environmental changes of LYZ, trypsin, and BHb. The results of molecular docking revealed that in LYZ and trypsin systems, LEV bound to the active sites residues GLU 35 and ASP 52 of LYZ and trypsin at the active site SER 195, and in BHb system, LEV was located in the central cavity, which was consistent with the results of synchronous fluorescence experiment. Besides, LEV made the activity of LYZ decrease while the activity of trypsin increased.

Investigation on the interaction of cefpirome sulfate with lysozyme by fluorescence quenching spectroscopy and synchronous fluorescence spectroscopy.

The reaction mechanism of cefpirome sulfate with lysozyme at different temperatures (298, 310 and 318 K) was investigated using fluorescence quenching and synchronous fluorescence spectroscopy under simulated physiological conditions. The results clearly demonstrated that cefpirome sulfate caused strong quenching of the fluorescence of lysozyme by a static quenching mechanism. The binding constants obtained using the above methods were of the same order of magnitude and very similar. Static electric forces played a key role in the interaction between cefpirome sulfate and lysozyme, and the number of binding sites in the interaction was close to 1. The values of Hill's coefficients were > 1, indicating that drugs or proteins showed a very weakly positive cooperativity in the system. In addition, the conclusions obtained from the two methods using the same equation were consistent. The results indicated that synchronous fluorescence spectrometry could be used to study the binding mechanism between drug and protein, and was a useful supplement to the fluorescence quenching method. In addition, the effect of cefpirome sulfate on the secondary structure of lysozyme was analyzed using circular dichroism spectroscopy.

Effect of PEAMA-g-PEG on the conformation of lysozyme by circular dichroism and florescence spectroscopy

Conjugation of biological (peptides/enzymes) and synthetic polymers has potential applications in both medicine and biotechnology. We have shown in our previous article that the enzymatic activity of lysozyme was suppressed by the complex formation with a cationic smart copolymer, poly(N,N-diethylaminoethyl methacrylate)-graft-poly(ethylene glycol) (PEAMA-g-PEG). In addition, the secondary structure of lysozyme was maintained. In the present study, tertiary structure of lysozyme were investigated using circular dichrosm (CD) and fluorescence spectroscopy. Near-UV CD spectral analysis clearly indicates that the complexation of lysozyme with PEAMA-g-PEG has almost no influence on the tertiary structure of lysozyme. Moreover, fluorescence spectrum of lysozyme and lysozyme complexed with PEAMA-g-PEG indicates the conformations of lysozyme were not disrupted.

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-C12 im]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-C12 im]Br2 through static quenching mechanism as confirmed by time resolved fluorescence spectroscopy. The binding constant for lysozyme-[C12-4-C12 im]Br2 interaction have been measured by UV-visible spectroscopy and found to be 2.541 × 10(5) M(-1). The FT-IR results show conformational changes in the secondary structure of lysozyme by the addition of [C12-4-C12 im]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-C12 im]Br2 complex reaches an equilibrium state at around 3 ns.

Probing the binding interaction of thionine with lysozyme: A spectroscopic and molecular docking investigation

In this article, an attempt is made to explore the binding mechanism of thionine with lysozyme by using multi-spectroscopic and molecular docking methods. The results from emission and time resolved fluorescence studies revealed that the emission quenching of lysozyme with thionine is initiated by static quenching mechanism. The binding constant and number of binding site of lysozyme–thionine complex was evaluated as 4.01 × 105 dm3 mol−1 and ≈1, respectively. Furthermore, the results from absorption, constant wavelength synchronous fluorescence, three dimensional emission and circular dichroism spectral studies showed that thionine induced conformational changes in the secondary structure of lysozyme. Molecular docking study confirmed that the probable binding site of thionine is located near trptophan-63 residue of lysozyme and it is further revealed that the existence of hydrogen bonding along with hydrophobic interaction are the primary forces responsible for the complexation of thionine with lysozyme.

Synthesis, structure, DNA/protein binding and in vitro cytotoxicity of new ruthenium metallates

The reaction of [RuHCl(CO)(PPh3)3] with an equimolar amount of salicylaldehyde-4(N)-methylthiosemicarbazone [H2-(Sal-mtsc)] resulted in two entities, namely [Ru(H-Sal-mtsc)Cl(CO) (PPh3)2] (1) and [Ru(Sal-mtsc)(CO)(PPh3)2] (2) from a single tub. The new complexes were characterized by various spectro (IR, absorption and NMR), analytical and single crystal X-ray diffraction studies. From the crystallographic studies, it is confirmed that in complex 1, the ligand coordinated through the thiolate sulfur and the deprotonated hydrazinic nitrogen N(2), resulting in the formation of an unusual strained four membered chelate ring. The third potential donor, phenolic oxygen, remained uncoordinated. In complex 2, the ligand coordinated as an ONS chelate with the formation of more common five and six membered chelate rings. Complexes 1 and 2 have been tested for their DNA/protein binding properties by taking CT-DNA/lysozyme as models. From the protein binding studies, the alterations in the secondary structure of lysozyme by the ruthenium(II) complexes (1 and 2) were confirmed with synchronous and three-dimensional fluorescence spectroscopic studies. The in vitro cytotoxicity of the newly-synthesized complexes was carried out in two different human tumour cell lines, A549 and HepG2. The cytotoxicity studies showed that complex 2 exhibited higher activity than 1.

Probing the interaction of lysozyme with ciprofloxacin in the presence of different-sized Ag nano-particles by multispectroscopic techniques and isothermal titration calorimetry

The binding of ciprofloxacin to lysozyme in the presence of three Ag nano-particles of varying sizes was for the first time investigated by multispectroscopic and isothermal titration calorimetry techniques at pH 7.4. The results indicated that ciprofloxacin quenched the fluorescence intensity of lysozyme through a static mechanism but in the presence of size-II Ag nano-particles, there were two kinds of interaction behaviors. The interaction between ciprofloxacin and lysozyme occurred via a second type of binding site, whereas in the presence of the Ag nano-particles, some changes occurred. The secondary structure of lysozyme–ciprofloxacin in the presence of Ag nano-particles was determined by circular dichroism. The thermodynamic parameters of the interaction between ciprofloxacin and lysozyme in the presence of Ag nano-particles were measured according to the van’t Hoff equation. The enthalpy (ΔH○) and entropy (ΔS○) changes were calculated to be −49.7 (kJ mol−1) and −20.1 (J mol−1 K−1), respectively, which indicated that the interaction of ciprofloxacin with lysozyme was driven mainly by van der Waals forces and hydrogen bonding. In the presence of the three different-sized Ag nano-particles, the enthalpic and the entropic changes were both negative which indicated that hydrogen bonding with van der Waals forces played major roles in the binding between ciprofloxacin and lysozyme. Recent developments in nano-materials offer new pathways for controlling the protein behavior through surface interactions. These data indicate that the recent research on nano-particle/protein interactions will emphasize the importance of such interactions in biological systems with applications including the diagnosis and treatment of human diseases.

Electromagnetic Fields Effects on the Secondary Structure of Lysozyme and Bioprotective Effectiveness of Trehalose

FTIR spectroscopy was used to investigate the effects of extremely low frequency (50 Hz) electromagnetic field and of microwaves at 900 MHz on the secondary structure of a typical protein, the lysozyme, evaluating the bioprotective effectiveness of trehalose. Lysozyme in D2O solution (60 mg/ml) was exposed to 50 Hz frequency electromagnetic field at 180 μT. The FTIR spectra indicated an increase of CH2 group at 1921 and 1853 cm−1 after 3 h of exposure. Such effect was not observed after the addition of trehalose (150 mg/mL) at the same exposure conditions. Lysozyme dissolved in D2O at the concentration of 100 mg/mL was exposed up to 4 h to 900 MHz mobile phone microwaves at 25 mA/m. A significant increase in intensity of the amide I vibration band in the secondary structure of the protein was observed after 4 h exposure to microwaves. This effect was inhibited by the presence of trehalose at the concentration of 150 mg/mL. Fourier self-deconvolution spectral analysis of lysozyme in D2O solution after exposure to microwaves revealed an increase in intensity of the conformational components of amide I mode, particularly of β-sheet and turn that can be attributed to disorder and unfolding processes of the protein.