Study of the Interactions of Fusarium virguliforme Toxin FvTox1 with Synthetic Peptides by Molecular Simulations and a Label-Free Biosensor.

Fusarium virguliforme is a soil borne pathogen that causes sudden death syndrome (SDS) in soybean plants. This pathogenic disease may result in severe soybean yield suppression and can cause serious economic harm. It has been shown that the FvTox1 toxin produced by the pathogen may be the root cause of foliar SDS. Anti-FvTox1 single-chain variable fragment antibody expressed in transgenic soybean plants was shown to neutralize the FvTox1 toxin involved in foliar SDS development. Here, we have investigated the binding affinities of FvTox1 with four FvTox1-interacting peptides of 7 to 12 amino acids identified from phage display libraries using both bioinformatics-based molecular simulations and label-free bioassays with a unique photonic crystal biosensor. Results from the molecular simulations have predicted the interaction energies and 3-dimensional (3D) structures of FvTox1 and FvTox1-interacting peptide complexes. Our label-free binding assays have further provided the interaction strength of FvTox1 with four different FvTox1-interacting peptides and experimentally confirmed the simulation results obtained from bioinformatics-based molecular calculations.