Molecular dynamics simulation of S. cerevisiae glucan destruction by plasma ROS based on ReaxFF

Atmospheric non-equilibrium plasma sterilization technology has been applied in the food processing, medical and health fields because of advantages such as short application time, low-temperature operation, high efficiency and safety. Research has shown that the active particles in the plasma play a decisive role in sterilization. However, the micromechanisms underlying the interaction between the active particles and biological components remain unclear. In this paper, with the common deteriorative microorganism Saccharomycodes as the research object, we examined the interaction between reactive oxygen species (O, OH, HO2 and H2O2) and glucan in the cell wall using a reactive force field molecular dynamics (ReaxFF MD) simulation methodology. We found that these reactive oxygen species reacted with the glucan structure by hydrogen abstraction reactions to cleave chemical bonds (C-O and C-C), resulting in cell wall destruction. Of these species, the O and OH species attract H atoms from the structure; these atoms are highly active and can easily break C-C bonds and release monosaccharides from the branched glucan chains. The H atoms in HO2 and H2O2 are strongly attracted to the glucan structure. Next, the C-O bonds are easily broken, leading to destruction of the chain structure, mainly because of the cleavage of the glucoside bonds. This simulation study adds to the understanding of the micromechanism of the ROS-mediated destruction of the cell wall glucan of Saccharomyces cerevisiae and of plasma sterilization at the atomic level.