Description
The secreted pore-forming protein listeriolysin O (LLO) is an essential virulence determinant of the facultative intracellular bacterium Listeria monocytogenes that allows the pathogen to escape from the phagocytic vacuole and reach the host cytosol. LLO is a single polypeptide protein encoded by the hlyA gene and composed of 529 residues. At its NH2-terminus it possesses a 25 residues long typical signal sequence excited during the secretion process. Moreover, in its NH2-terminus there is also a 19 amino acids PEST- like sequence that may target this toxin for degradation. This motif seems to be essential for bacterial virulence too, since its deletion causes a defect in bacterium phagosomal escaping