Grant: Operating Grant

Pseudomonas aeruginosa is an important opportunistic pathogen that can cause fatal infections in individuals compromised by burn wounds, cystic fibrosis, and other conditions. This bacterial species produces two forms of lipopolysaccharides (LPS) on its cell surface, one contains an O antigen (called B band, serotype specific), and the other contains a common polysaccharide antigen (called A band). B band is a major virulence factor, while A band is important for P. aeruginosa to adhere to human airway epithelia. Interestingly, LPS and capsules from P. aeruginosa and a host of other bacterial pathogens are composed of rare sugars not found in humans. My laboratory has been using genetic and biochemical methods to investigate how this LPS coat is made. This line of research has high translational potential because the knowledge derived from our work could lead to the identification of specific targets that can be used for high throughput screening to identify novel antibiotics against bacterial pathogens. Our Specific Aims in this proposal include: 1) To perform functional characterization of each of the genes in the 5-gene operon (pa5455-pa5499) and to determine their role in A-band biosynthesis. 2) To test the hypothesis that the catalytic activities of GMD and RMD can switch from dehydratase to reductase or vice versa by amino acid switches in the catalytic triad. 3) To characterize hisH2, hisF2 and wbpG that are important for O-specific polysaccharide biosynthesis and production of rare acetamidino sugars in P. aeruginosa. 4) To use cutting edge super-resolution 3D-structured illumination microscopy for live-cell imaging to investigate the spatial localization of A-band and B-band LPS.