Pore Formation Mechanism of Staphylococcal Pore- forming Toxin

Y. Tanaka and M. Yao (Hokkaido Univ.) Pathogenic bacteria express pore-forming toxins (PFTs) to attack host cells. PFTs are expressed as soluble monomeric proteins, which assemble to prepore oligomer on the target cells. After forming prepore, conformational change occurs, and then the pore is formed. Although the crystal structures of monomer and pore have been determined, the detailed mechanism was unclear because the high-resolution structure of prepore was unknown. In this study, we determined the crystal structure of the prepore of staphylococcal PFTs, which showed an invisible transmembrane region with rigid other parts. Based on the structural information and biochemical data, we propose a two-step transmembrane pore formation mechanism.