Investigating a Cytoplasmic Metal-Dependent Protein in Pseudomonas Aeruginosa

Diplôme Master Investigating a Cytoplasmic Metal-Dependent Protein in Pseudomonas Aeruginosa eng 2025-09-09 2025-08-29 author Liatti Pablo 944641 director Perron Karl 45679 Département des sciences végétales (BIVEG) 43 Pseudomonas aeruginosa is a ubiquitous Gram-negative bacterium, known for its high virulence and its broad anti-microbial resistance. Due to its direct contact with the environment, particularly with heavy metals, P. aeruginosa must possess effective regulatory systems to maintain metal homeostasis in the cell. The regulator CadR is one of the key players for the early response against an excess of zinc. Its role is to activate the P-type ATPase pump CadA so it can expulse the excess of zinc in the periplasm. Here we investigated a new zinc-dependent protein, regulated by CadR and induced in the presence of excess Zn, called 9kD. We found that deletion in 9kD gene leads to higher sensitivity to either zinc and cadmium and delays the growth in presence of zinc. Fractioning of the cell has shown the 3xFLAG protein tagged localizes in the cytoplasm and no evidence for DNA binding was found. Two hybrid bacterial analysis was conducted to find protein-protein interaction with 9kD. From this experiment we found two potential candidates, but further investigation revealed an out of frame compared to the adenylate cyclase fragment in pUT18 for one candidate and mismatches in the amino acid sequence compared to the respective reference protein for the other candidate. Finally, we analyzed the expression of the promoter operon encoding the CzcCBA efflux pump in a PAO1 strain deleted for 9kD. We found a decrease in the promoter expression similarly to PAO1 cadA deleted strain. This study investigates the role of a novel protein, and many other aspects of its function must be characterized. Dewey 580 45 Département des sciences végétales 163 false 4f096380-695b-448e-8b7f-df68c025a3fc Master thesis Restricted Mémoire_Master_Pablo_Liatti.pdf 1473530 application/pdf d218e7d5481ad4466912a1bcf229a3d09b0ad0308f7f115d125e0e215add440b restrictedAccess Faculté des sciences / Section de biologie / Département des sciences végétales

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Investigating a Cytoplasmic Metal-Dependent Protein in Pseudomonas Aeruginosa				2025	21	3

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