Ribotoxin-like proteins from Boletus edulis: structural properties, cytotoxicity and in vitro digestibility

Porcini are edible mushrooms widely used in cooking due to their extraordinary taste. Despite this, cases of food poisoning have been reported in the recent literature also for ingestion of porcini. Here, we report the isolation from Boletus edulis fruiting bodies of two novel ribotoxin-like proteins (RL-Ps), enzymes already studied in other organisms for their toxicity. These RL-Ps, named Edulitin 1 (16-kDa) and Edulitin 2 (14-kDa), show peculiar structural and enzymatic differences, which probably reflect their different bio-activities and a dose/time dependent toxicity (Edulitin 2) on normal and tumoral human cells. Particularly interesting is the resistance to proteolysis of Edulitin 2, for which it was observed that its toxicity was abolished only after heat treatment (90 degrees C) followed by proteolysis. As mushroom poisoning is a serious food safety issue, data here presented confirm the existence of toxins also in porcini and the importance of a proper cooking before their consumption.

Automated summary

Porcini mushrooms are widely used in cooking for their excellent taste, but cases of food poisoning have been reported recently. Two novel ribotoxin-like proteins have been isolated from Boletus edulis mushrooms, showing different toxic activities on normal and tumoral human cells. Proper cooking of porcini mushrooms is crucial to prevent poisoning due to the presence of these toxins.