In Silico comparative analysis of type III secretion system effector proteins of Pseudomonas aeruginosa as agents of Acanthamoeba spp. killing

The Type III Secretion System (T3SS) of Pseudomonas aeruginosa plays a critical role in its pathogenicity by delivering effector proteins directly into host cells. This study conducted an in silico comparative analysis of four T3SS effector proteins (ExoS, ExoT, ExoU, and ExoY) to elucidate their molecular mechanisms in targeting Acanthamoeba spp., a genus of free-living amoebae with significant public health implications. Using bioinformatic tools, we examined the molecular structures, physicochemical properties, and cytotoxic mechanisms of these effectors. Structural characterization revealed distinct functional domains: ExoS and ExoT share overlapping activities but differ in their mechanisms, with ExoS disrupting cellular processes via ADP-ribosyltransferase activity and ExoT impairing phagocytosis through its GTPase-activating protein domain. ExoU’s phospholipase activity leads to membrane disruption and necrotic cell death, while ExoY interferes with cytoskeletal integrity through adenylate cyclase activity, increasing intracellular cAMP levels. Molecular docking analyses demonstrated stable binding interactions between these effectors and Acanthamoeba castellanii, highlighting their specific cytotoxic pathways. These findings provided insights into the pathogenesis of P. aeruginosa and offer a foundation for the development of novel therapeutic strategies against Acanthamoeba infections.