Ageritin from Pioppino Mushroom: The Prototype of Ribotoxin-Like Proteins, a Novel Family of Specific Ribonucleases in Edible Mushrooms.

Ageritin is a specific ribonuclease, extracted from the edible mushroom Cyclocybe aegerita (synonym Agrocybe aegerita ), which cleaves a single phosphodiester bond located within the universally conserved alpha-sarcin loop (SRL) of 23-28S rRNAs. This cleavage leads to the inhibition of protein biosynthesis, followed by cellular death through apoptosis. The structural and enzymatic properties show that Ageritin is the prototype of a novel specific ribonucleases family named 'ribotoxin-like proteins', recently found in fruiting bodies of other edible basidiomycetes mushrooms (e.g., Ostreatin from Pleurotus ostreatus , Edulitins from Boletus edulis , and Gambositin from Calocybe gambosa ). Although the putative role of this toxin, present in high amount in fruiting body (>2.5 mg per 100 g) of C. aegerita, is unknown, its antifungal and insecticidal actions strongly support a role in defense mechanisms. Thus, in this review, we focus on structural, biological, antipathogenic, and enzymatic characteristics of this ribotoxin-like protein. We also highlight its biological relevance and potential biotechnological applications in agriculture as a bio-pesticide and in biomedicine as a therapeutic and diagnostic agent.