(648d) Computational Modeling and Simulation Studies on the Binding of Toxic Compounds to Montmorillonite Clay

In the event of flooding or hurricanes, soil and sediment contaminated with toxic chemical compounds can be transported to areas where high level human contact can occur, such as lawns, gardens, and even water supplies. It is known that several toxic compounds bind to soil containing clays due to the affinity between them. Therefore, montmorillonite clay has been suggested as a sorbent that can be integrated into the diet of humans or animals to combat the exposure and toxicity of such toxic compounds [1]. However, the binding mechanisms are not well understood on an atomistic level. This limits the use of computational screening methods for potential toxins and the development of novel sorbent amendments that can facilitate toxin binding on active surfaces of clay. Here, we modeled montmorillonite clay in complex with toxic compounds and used multi-ns molecular dynamics simulations in CHARMM. Subsequently, we used in-house developed programs for structure analysis to investigate the binding of toxic compounds to the clay. Our results can reveal the key modes of interactions and driving forces leading to toxic compounds’ binding to the clay. Experiments and simulations are consistent with each other and show the importance of different pH conditions on the binding of toxic compounds to the clay. The insights provided by the simulations can be used for the discovery and design of novel amending compounds that can facilitate the adsorption of toxins on surfaces of the clay.

[1] Meichen Wang, Cody R. Maki, Youjun Deng, Yanan Tian, and Timothy D. Phillips, Development of High Capacity Enterosorbents for Aflatoxin B1 and Other Hazardous Chemicals, Chemical Research in Toxicology 2017 30 (9), 1694-1701, DOI:10.1021/acs.chemrestox.7b00154