Interaction of carbon nanotubes with microbial enzymes: Conformational transitions and potential toxicity

Abstract

Wide industrial, environmental and biomedical applications of carbon nanotubes (CNTs) are allowing them to enter the environment. Their toxicity to microorganisms has been experimentally reported, but the underlying molecular mechanism is still unclear. Here, we investigated the conformational transitions in widely distributed microbial enzymes in the presence and absence of single-walled carbon nanotubes (SWCNTs) by molecular dynamics (MD) simulations. Our study identifies a new mechanism by which SWCNTs produce possible toxicity to microbes by inducing significant changes in enzymatic conformations. The protein-protein interactions undergo significant transitions in two monomers, either towards or away from each other in the presence of SWCNTs. The significant conformational changes in microbial enzymes may inactivate the microbial enzymes and disturb the microbial metabolism.