Premium
Simultaneous Occurrence of Energy Transfer and Photoinduced Electron Transfer in Interactions of Hen Egg White Lysozyme with 4‐Nitroquinoline‐1‐Oxide
Author(s) -
Banerjee Mousumi,
Maiti Sourav,
Kundu Ipsita,
Chakrabarti Abhijit,
Basu Samita
Publication year - 2010
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/j.1751-1097.2010.00811.x
Subject(s) - chemistry , förster resonance energy transfer , lysozyme , flash photolysis , quenching (fluorescence) , electron transfer , tryptophan , photochemistry , ultrafast laser spectroscopy , photoinduced electron transfer , circular dichroism , fluorescence , analytical chemistry (journal) , spectroscopy , reaction rate constant , crystallography , kinetics , chromatography , biochemistry , physics , amino acid , quantum mechanics
The carcinogenic drug 4‐nitroquinoline‐1‐oxide (4NQO) has been found to bind with the protein hen egg white lysozyme as evident from fluorescence quenching experiments. The binding constant and stoichiometry have been determined. The values of the thermodynamic parameters indicate that the interaction is an enthalpy‐driven spontaneous phenomenon. The experimental value of change in free energy is similar to that obtained from the docking study. The far UV circular dichroism spectra show some changes in the secondary structure of protein. The high value of bimolecular quenching constant leads to the possibility of Förster resonance energy transfer (FRET). Along with FRET, the photoinduced electron transfer (PET) from tryptophan residue of protein to 4NQO has also been evident from the transient absorption spectra obtained in laser flash photolysis experiments. The simultaneous occurrence of FRET and PET is the key factor for quenching of intrinsic fluorescence of the protein as it binds with the drug.