Interaction of the insecticide bioallethrin with human hemoglobin: biophysical, in silico and enzymatic studies

Abstract

Bioallethrin is an insecticide that is widely used in households resulting in human exposure. Bioallethrin is cytotoxic to human erythrocytes. Here we have studied the interaction of bioallethrin with human hemoglobin (Hb) using in silico and biophysical approaches. Incubation of Hb (5 μM) with bioallethrin (1–50 µM) led to increase in absorbance at 280 nm while the Soret band at 406 nm was slightly reduced. The intrinsic fluorescence of Hb was enhanced with the appearance of a new peak around 305 nm. Synchronous fluorescence showed that the binding of bioallethrin to Hb mainly affects the tyrosine microenvironment. The structural changes in Hb were confirmed with a significant shift in CD spectra and about 25% loss of α-helix. Molecular docking and visualisation through Discovery studio confirmed the formation of Hb-bioallethrin complex with a binding energy of –7.3 kcal/mol. Molecular simulation showed the stability and energy dynamics of the binding reaction between bioallethrin and Hb. The structural changes induced by bioallethrin led to inhibition of the esterase activity of Hb. In conclusion, this study shows that bioallethrin forms a stable complex with human Hb which may lead to loss of Hb function in the body.

Communicated by Ramaswamy H. Sarma

Graphical representation showing structural changes, enzymatic alteration upon complex formation between BA and Hb with different in vitro and in silico approaches. This study shows that a stable Hb:BA complex is formed which results in structural changes in human Hb and also inhibits its esterase activity. These changes will further affect the normal functioning of Hb and may cause blood related clinical issues in the BA exposed population.

Keywords:

• Hemoglobin
• bioallethrin
• synchronous fluorescence
• spectroscopy
• MD simulations
• esterase activity

Acknowledgements

Authors thank the Departments of Biochemistry and Biotechnology, Faculty of Life Sciences, A.M.U. for providing facilities for this study. We greatly appreciate the support and help, during experiments and editing, from lab mates including Ruhul Quds, Zarmin Iqbal and Monica Sharma.

Disclosure statement

The authors declare no competing financial interest.

Additional information

Funding

A.A. and S.S. are recipients of Senior Research Fellowships from ICMR-SRF and UGC-MANF, respectively, and we thank these funding agencies for the fellowships provided.