Investigation on the Interaction between Cyclophosphamide and Lysozyme in the Presence of Three Different Kind of Cyclodextrins: Determination of the Binding Mechanism by Spectroscopic and Molecular Modeling Techniques

Abstract

The interactions between cyclophosphamide (CYC) and lysozyme (LYZ) in the presence of different cyclodextrins (CDs) were investigated by UV absorption, fluorescence spectroscopy, circular dichroism (CD), and molecular modeling techniques under imitated physiological conditions. The UV absorption results showed the formation of complexes between CYC and LYZ in the presence of different CDs. Fluorescence data show that CYC has a stronger quenching effect on LYZ, and the red shifts suggested that the microenvironment of Trp residues was changed and became more hydrophilic. The interaction of CYC with LYZ and quenching properties of the complexes caused strong static fluorescence quenching in binary and ternary systems. The binding affinities as well as the number of binding sites were obtained from interaction between CYC and LYZ in the presence of different CDs as binary and ternary systems by modified Stern-Volmer plots. The Resonance Light Scattering (RLS) technique was utilized to investigate the effect of drug and CDs on conformational changes of LYZ as separate and simultaneous. The results suggested that the enhancement of RLS intensity was attributed to the formation of a complex between drug and protein in absence and presence of CDs. The effect of CYC and cyclodextrins on the conformation of LYZ was analyzed using synchronous fluorescence spectroscopy. Our results revealed that the fluorescence quenching of LYZ originated from the Trp and Tyr residues, and demonstrated conformational changes of LYZ with the addition of CYC and CDs. The molecular distances between the donor (LYZ) and acceptor (CYC and CDs) in binary and ternary systems were estimated according to Forster’s theory and showed static quenching for protein with CYC in the presence of CDs. The CD spectra indicated that the binding of the CYC induced secondary structural changes in LYZ in binary and ternary systems. Molecular modeling suggested the binding sites of CYC in the ternary systems differ from those in the binary systems. estimated the distance between CYC and Trp residues in binary and ternary systems in the presence of CDs and confirmed the experimental results.

Spectroscopic investigation on the food components–drug interaction: The influence of flavonoids on the affinity of nifedipine to human serum albumin

“…Synchronous fluorescence spectra can provide the information about the conformational changes of protein since the shift of the maximum emission wavelength correlates with changes of the polarity around the chromophores (Zhang et al, 2010a(Zhang et al, , 2010b. As the Δλ between the excitation wavelength and emission wavelength is 15 nm, synchronous fluorescence spectrum offers information about characteristics of the tyrosine residues, while when Δλ is 60 nm it provides characteristic information about the tryptophan residues (Mansouri et al, 2013). The synchronous fluorescence spectra of HSA at various concentrations of NDP for the tyrosine residues and the tryptophan residues are shown in Fig.…”

Ameliorative Effect of Carob Pods Extract (Ceratonia siliqua L.) against Cyclophosphamide Induced Alterations in Bone Marrow and Spleen of Rats

“…This may be due to binding CYP with native macromolecules inducing secondary structural changes in the enzyme (Mansouri et al, 2013). In addition, the alterations in CAT pattern may refer to effect of CYP on thymus and spleen through inducing immunosuppression (Wei et al, 2011).…”

DietaryApostichopus japonicusenhances the respiratory and intestinal mucosal immunity in immunosuppressive mice

“…Cyclophosphamide could reduce the activity of lysozyme. 24,25) Local lysozyme deficiency may contribute to the pathogenesis of recurrent sinusitis, hyaline membrane disease, and early stage cystic fibrosis. Our study showed that cyclophosphamide caused the decrease of lysozyme expression in both lungs and guts.…”