New insights into searching patulin degrading enzymes in Saccharomyces cerevisiae through proteomic and molecular docking analysis

Global warming has increased the contamination of mycotoxins. Patulin (PAT) is a harmful contaminant that poses a serious threat to food safety and human health. Saccharomyces cerevisiae biodegrades PAT by its enzymes during fermentation, which is a safe and efficient method of detoxification. However, the key degradation enzymes remain unclear. In this study, the proteomic differences of Saccharomyces cerevisiae under PAT stress were investigated. The results showed that the proteins involved in redox reactions and defense mechanisms were significantly up-regulated to resist PAT stress. Subsequently, molecular docking was used to virtual screen for degrading enzymes. Among 18 proteins, YKL069W showed the highest binding affinity to PAT and was then expressed in Escherichia coli, where the purified YKL069W completely degraded 10 μg/mL PAT at 48 h. YKL069W was demonstrated to be able to degrade PAT into E-ascladiol. Molecular dynamics simulations confirmed that YKL069W was stable in catalyzing PAT degradation with a binding free energy of -7.5 kcal/mol. Furthermore, it was hypothesized that CYS125 and CYS101 were the key amino acid residues for degradation. This study offers new insights for the rapid screening and development of PAT degrading enzymes and provides a theoretical basis for the detoxification of mycotoxins. Patulin, mainly produced by Penicillium expansum, is a mycotoxin in fruits and has also been detected in other food and feed chains. Due to its toxicity, patulin contamination poses a risk to food safety, environment and human health. Although researchers have focused on patulin removal by biological methods in recent decades, the degrading enzymes remain poorly investigated. In this study, YKL069W was screened as a key enzyme in Saccharomyces cerevisiae for patulin degradation using proteomics and molecular docking, which efficiently degraded patulin. This work solved the non-targeted screening and uncontrollable experimental periods and provide new insights into detoxification of mycotoxin.