Identification of drug targets and drug leads in Pseudomonas aeruginosa.

摘要

Pseudomonas aeruginosa is a major human pathogen that is naturally resistant to many of the antibiotics currently used to treat microbial infections. It ranks second among all Gram-negative bacteria that pose antibiotic resistance in immunocompromised patients. When 16S rRNA from P. aeruginosa was expressed in the Cunningham lab genetic system, ribosome function was decreased to 46%. Replacement of H9 region from E. coli or the expression of P. aeruginosa S20 protein restored the ribosome function to full amount. We have found that decreased amount of ribosome function in the system containing Pa16S rRNA is due to defect in ribosome assembly. These findings suggest that there is species specific interaction of S20 and helix 9 in P. aeruginosa . Fluorescent binding studies were also performed to validate species-specific interaction.; Taking advantage of species specific interaction, we want to discover narrow spectrum anti-infectives that can specifically bind to species-specific target in P. aeruginosa. Ribosomal protein S20 and helix 9 were independently used as bait to identify peptide molecules that have potential to disrupt H9-S20 interaction in P. aeruginosa by screening phage display libraries. Ph. D. 7 mer M13 phage display libraries were screened against each of the target and consensus peptide sequences have been identified. Some of the peptides isolated from phage display of helix 9 were characterized by ELISA. One of the peptide sequences, HWGMWSY was seen to bind tightest among all peptides selected against helix 9. Optimization and refinement of one of the peptides, using rational drug design and peptidomimetic chemistry might have potential to inhibit growth of P. aeruginosa .