Title
Spectroscopic evaluation of the interaction between pesticides and chickpea cystatin: comparative binding and toxicity analyses
Author
Sheraz Ahmad Bhat, Waseem Feeroze Bhat,Bilqees Bano
Year
2016
Journal
Environmental Science: Processes & Impacts
Abstract
The binding study of pesticides with proteins is of great importance in ecotoxicology. In this study, a comparative interaction mechanism of phytocystatin with three pesticides has been presented, each from a different class- glyphosate herbicide (GPS), Chlorpyrifos insecticide (CPF), and Mancozeb fungicide (MCZ). The interaction of purified chickpea cystatin (CPC), has been characterized by fluorescence, UV, Fourier transform infrared (FT-IR), Circular dichroism (CD) spectroscopic methods. The study revealed association constants (Ka) of 52 M-1, 1.145 x 103 M-1, and 36.12 M-1 for the interaction of CPF, MCZ, and GPS with CPC respectively, signifying the high affinity interaction for MCZ. Structural changes (at tertiary and secondary level) were confirmed by UV-visible, intrinsic fluorescence and CD spectroscopies. The results showed that the effect on CPC structure was more pronounced in case of MCZ, which was followed by CPF and then GPS. The functional analysis of the pesticide treated inhibitor showed decline in antipapain activity which varied with the time, dose as well as class of pesticide. MCZ was relatively much more toxic as compared to CPF and GPS. Reactive oxygen species responsible for inhibitor damage were also analyzed. Results obtained implicate that the exposure of plants to pesticides may lead to physicochemical changes in the proteins such as phytocystatin leading to physiological damage to the plant system.
Instrument
J-815
Keywords
Circular dichroism, Agricultural and environmental, Ligand binding, Secondary structure, Biochemistry