Probing Human Tubulins-Phomopsins Interaction: an in Silico Approach for a Mechanism-Based Hazard Prioritisation of the Phomopsin Family.

Phomopsins are mycotoxins mainly contaminating lupin-derived food matrices posing safety concerns, with phomopsin A considered the most potent congener. Their toxicity is linked to disruption of microtubule dynamics, yet the shortage of toxicokinetic and toxicodynamic data prevents adequate human risk assessment, representing a critical gap for food safety. To bridge this data gap through New Approach Methodologies (NAMs), a computational 3D modelling pipeline, combining molecular dynamics simulations and binding free energy calculations, was applied to investigate the interactions of phomopsin A and selected congeners with the human α/β-tubulin assembly. The whole set of phomopsins showed a comparable mode of binding, with some exhibiting geometrically and energetically distinct, yet comparably stable, interaction profiles. Dechlorination emerged as a critical destabilising factor. By enabling a mechanism-based read-across across the congeneric series, these findings provide a supported hazard prioritisation of phomopsin analogues, identifying phomopsin A, iso-phomopsin A, and phomopsinamine A as high-priority compounds for toxicological investigation. Overall, this NAMs-driven approach sets the groundwork for a more informed hazard characterisation and mechanistic interpretation of the phomopsin family. By helping prioritise which congeners warrant further investigation, it also provides a useful basis for future human exposure assessment, once complemented by toxicokinetic and occurrence data.