Interaction of Human Alpha-2-Macroglobulin with Pesticide Aldicarb Using Spectroscopy and Molecular Docking

Background: Aldicarb is a carbamate pesticide commercially used in potato crop production. Once it enters human body, it interacts with diverse proteins and other substances.

Objective: Aldicarb is toxic to human health and it is also a cholinesterase inhibitor, which prevents the breakdown of acetylcholine in synapse. Human alpha-2-macroglobulin (α2M), is a large tetrameric glycoprotein of 720 kDa with antiproteinase activity, found abundantly in plasma.

Methods: In the present study, the interaction of aldicarb with alpha-2-macroglobulin was explored utilizing various spectroscopic techniques and molecular docking studies.

Results: UV-vis and fluorescence spectroscopy suggests the formation of a complex between aldicarb and α2M apparent by increased absorbance and decreased fluorescence with static quenching mode. CD spectroscopy indicates a slight change in the structure of alpha-2-macroglobulin. Docking studies confirm the interaction of aldicarb with Pro- 1391, Leu-1392, Lys-1393, Val-1396, Lys- 1397, Thr-1408, Glu-1409, Val-1410, Asp-282 and Glu-281 in the receptor binding domain at the C-terminal of the alpha 2 macroglobulin.

Discussion: In this work, aldicarb is shown to bind with alpha 2-macroglobulin at receptor binding domain which is the binding site for various extracellular and intracellular ligand too. Also, affecting the functional activity of the protein may lead to further physiological consequences.

Conclusion: It is possible that aldicarb binds and compromises antiproteinase activity of α2M and binding properties by inducing changes in the secondary structure of the protein.