Thionins are small plant proteins which are toxic to animal cells. They seem to exert their toxic effect at the level of the cell membrane. Their precise function is not known. The predicted 3D structure shares similarity with the HTH DNA-binding motifs, leading to the suggestion that the intracellular thionins of an infected plant may activate signaling networks that regulate innate responses, including the hypersensitive reaction. Belongs to the plant thionin (TC 1.C.44) family.