Analyzing protein interactions in bacteria that cause diseases

Pseudomonas aeruginosa is a gram-negative, opportunistic bacterium that is known to cause disease in burns victims, patients with Cystic Fibrosis, and immunocompromised patients. P. aeruginosa utilizes the Type III Secretion System (T3SS) to directly inject toxins into a eukaryotic cell's cytoplasm. The T3SS resembles a needle-like projection from the bacterial surface to the eukaryotic cell membrane and consists of an injectisome, needle, and tip complex.

It has been proposed that toxic effectors are secreted through a proteinacious pore known as a translocon, which is formed by the secreted pore-forming proteins PopB and PopD. The secreted hydrophobic translocators PopB and PopD interact with their cognate chaperone PcrH in vivo, which keeps them in a secretion competent state. A partial crystal structure of PcrH in complex with a short, synthetic nine-residue segment of the proposed chaperone-binding motif of PopB has been solved.

The partial crystal structure data was used to generate a model of the interaction between PcrH and PopB. Although the partial crystal structure provides insight into the interaction between PopB and PcrH, the proposed model has not been verified for the interaction between full length PopB and PcrH. This project will be used to verify the modeled interaction between full length PopB and PcrH proteins. The knowledge generated by this project can be used for research pertaining to antibiotic resistance.