Résumé
MAX effectors are a family of proteins widely distributed in the phytopathogen fungus Magnaporthe oryzae that share a conserved 3D structure despite low sequence identity. These effectors family of almost 100 members constitute the molecular arsenal for the fungus infection and contribute to the pathogenicity of the plant pathogen that causes blast disease of a wide variety of cereals. Determining the structure of these effectors is a challenging case study that was overcome by the development of a prediction pipeline combined with modeling using the Alphafold software. After sequence screening of M. oryzae secretomes and identification of MAX effectors the Alphafold models were confronted with experimentally validated NMR structures. The compilation of models and experimental structures highlighted the existence of variability within this structural family that was essentially reflected by the existence of structured N- or C-terminal extensions beyond the preserved MAX core. Folding pathways were studied by High Pressure NMR to further characterize folding intermediates that involved elements of the MAX core but also additional extensions. Taken together, this work constitutes the first step in mapping the functional network of these effectors through their structure by identifying possible interacting sites within the MAX effectors that are useful to prioritize plant biology studies of infected hosts.