title: Elucidation of Binding Mechanism of Photodynamic Therapeutic Agent Toluidine Blue O with Chicken Egg White Lysozyme by Spectroscopic and Molecular Dynamics Studies.
abstract: The nature of binding mechanism of toluidine blue O (TBO) with chicken egg white lysozyme was studied comprehensively by various spectroscopic and computational methods. Both steady state and time-resolved fluorescence studies unambiguously point to the prevalence of static quenching mechanism in lysozyme-TBO system. Thermodynamic parameters revealed that the association of TBO with lysozyme was a spontaneous process in which hydrophobic and hydrogen bond interactions played a pivotal role in the binding process. The secondary and tertiary conformational changes of lysozyme in the presence of TBO were unraveled using absorption, Fourier transform infrared spectroscopy (FT-IR) and circular dichroism (CD) techniques. Molecular docking studies of lysozyme-TBO system substantiated the findings of site marker experiment and revealed TBO adjacent to Trp-63 and Trp-108 residues of lysozyme. Molecular dynamics (MD) simulation studies of lysozyme-TBO system indicate a stable and effective complexation of TBO with lysozyme. It is hoped that the results presented here will enable further understanding of TBO toxicity.
authors.affiliation: Department of Chemistry, Bharathiar University, Coimbatore, Tamil Nadu, India.
authors.forename: Krishnamoorthy
authors.initials: K
authors.lastname: Shanmugaraj
authors.affiliation: Department of Physics, Bharathiar University, Coimbatore, Tamil Nadu, India.
authors.forename: Palanivel
authors.initials: P
authors.lastname: Umadevi
authors.affiliation: Department of Physics, Bharathiar University, Coimbatore, Tamil Nadu, India.
authors.forename: Lakshmipathi
authors.initials: L
authors.lastname: Senthilkumar
authors.affiliation: Department of Chemistry, Bharathiar University, Coimbatore, Tamil Nadu, India.
authors.forename: Malaichamy
authors.initials: M
authors.lastname: Ilanchelian
mesh_terms: D000818:Animals; D002645:Chickens; D002942:Circular Dichroism; D004527:Egg Proteins / Q000737:chemistry / Q000378:metabolism*; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D062105:Molecular Docking Simulation; D056004:Molecular Dynamics Simulation; D009113:Muramidase / Q000737:chemistry / Q000378:metabolism*; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000378:metabolism*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics; D014048:Tolonium Chloride / Q000378:metabolism*
chemical_list: D004527:Egg Proteins; D017319:Photosensitizing Agents; D014048:Tolonium Chloride; C421864:hen egg lysozyme; D009113:Muramidase