Grant: Operating Grant

Pseudomonas aeruginosa is a serious opportunistic and hospital-acquired pathogen, infecting burn, cancer, HIV and cystic fibrosis patients, as well as causing eye, ear and wound infections. It is rapidly becoming resistant to most antibiotics, so alternate strategies to prevent P. aeruginosa infections are urgently needed. P. aeruginosa uses long fibres called type IV pili (T4P) to stick to living tissue and to non-living materials such as catheters. T4P are also used for motility, allowing the bacteria to spread from the initial site of infection. Without its T4P, P. aeruginosa is impaired in causing disease, so T4P are great targets for new vaccines or drugs. We are investigating the functions of a group of 7 proteins that we believe work together to assemble a large hole in the cell envelope through which the pili exits to the outside of the cell. The correct assembly of this hole in the cell envelope, which has mulitple layers, is crucial to permit pili to appear on the cell surface, while maintaining cellular integrity. Our preliminary data show that removing any of any of these proteins results in either misassembly, or no assembly at all of the large outer membrane hole. We will use a number of complementary techniques ranging from microbiological, biochemical and biophysical approaches to structural biology to characterize the proposed complex, including determining each protein's atomic structure, and investigation of the specific function of each component. Together, all of this information will let us put these 3D puzzle pieces in the right order to get an accurate picture of the pilus assembly complex and identify points of vulnerability that could be exploited for development of 'pilicides'.