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Elucidation of Binding Mechanism of Photodynamic Therapeutic Agent Toluidine Blue O with Chicken Egg White Lysozyme by Spectroscopic and Molecular Dynamics Studies
Author(s) -
Shanmugaraj Krishnamoorthy,
Umadevi Palanivel,
Senthilkumar Lakshmipathi,
Ilanchelian Malaichamy
Publication year - 2017
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/php.12744
Subject(s) - lysozyme , chemistry , egg white , hydrogen bond , fourier transform infrared spectroscopy , circular dichroism , molecular dynamics , quenching (fluorescence) , photochemistry , fluorescence , molecule , biophysics , crystallography , computational chemistry , organic chemistry , chemical engineering , biochemistry , biology , physics , quantum mechanics , engineering
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.