Présentation sous forme d’affiche au congrès CSM (Canadian Society of Microbiology) à Laval le 26 mai 2003.

Paradis-Bleau, C., Sanschagrin, F. and Levesque, R.C. 2003. Molecular studies of Pseudomonas aeruginosa FtsA and FtsZ interactions and screening for ATPase peptide inhibitors of FtsA by phage display. 53rd Annual Meeting of the Canadian Society for Microbiologists, Laval, Quebec. May 25 to 28, 2003.

The complete 6.3 Mpb genome sequence and the resistance of the opportunistic pathogen Pseudomonas aeruginosa to most classes of antibiotics represent a genomics tool for identification of novel targets for new antibacterials. With the prospect of finding new inhibitors of prokaryotic cell division, we screened for ATPase peptide inhibitors of FtsA and studied the interaction of two essential proteins: FtsA and FtsZ. As a first step, purified FtsA from P. aeruginosa was used to carry out each of the 3 rounds of phage display with the C-7-C and the 12-mers libraries containing 109 different peptides. The specificity of the 3 rounds of biopanning was raised by increasing the stringency of the wash and by decreasing the time of contact between the peptide and the protein. A competitive elution was done with 1 mM ATP and 5’-adenylylimidodiphosphate (a non-hydrolysable analogue of ATP). Peptides were isolated as phages and DNA of 20 phages per screening were sequenced. We identified many peptide sequences witch could be ATPase peptide inhibitors of FtsA. A competitive elution with FtsZ gave us 2 consensus peptide sequences. These promising peptides were synthesised as they could also be inhibitors of the FtsA-FtsZ interaction. To characterize the effect of these peptides, we developed a new protein-protein interaction assay. FtsA was coated in a microplate well and biotinylated FtsZ was added. HRP-streptavidine and its substrate ABTS were used to quantify the FtsA-FtsZ interaction. This interaction is essential for the constriction of the Z-ring and is sensitive to this specific alteration witch can be quantified in vitro . Analysis technique coupled to in vivo whole bacteria cell monitoring is a promising approach for the identification of new antimicrobial agents via high throughput screening in vivo .