@article {271, title = {Small Molecule Inhibition of an Exopolysaccharide Modification Enzyme is a Viable Strategy To Block Pseudomonas aeruginosa Pel Biofilm Formation}, journal = {Microbiology Spectrum}, volume = {11}, year = {2023}, month = {04/2023}, abstract = {

Biosynthesis of the Pel exopolysaccharide in\ Pseudomonas aeruginosa\ requires all seven genes of the\ pelABCDEFG\ operon. The periplasmic modification enzyme PelA contains a C-terminal deacetylase domain that is necessary for Pel-dependent biofilm formation. Herein, we show that extracellular Pel is not produced by a\ P. aeruginosa\ PelA deacetylase mutant. This positions PelA deacetylase activity as an attractive target to prevent Pel-dependent biofilm formation. Using a high-throughput screen (n = 69,360), we identified 56 compounds that potentially inhibit PelA esterase activity, the first enzymatic step in the deacetylase reaction. A secondary biofilm inhibition assay identified methyl 2-(2-pyridinylmethylene) hydrazinecarbodithioate (SK-017154-O) as a specific Pel-dependent biofilm inhibitor. Structure-activity relationship studies identified the thiocarbazate as a necessary functional group and that the pyridyl ring could be replaced with a phenyl substituent (compound 1). Both SK-017154-O and compound 1 inhibit Pel-dependent biofilm formation in\ Bacillus cereus\ ATCC 10987, which has a predicted extracellular PelA deacetylase in its\ pel\ operon. Michaelis-Menten kinetics determined SK-017154-O to be a noncompetitive inhibitor of PelA, while compound 1 did not directly inhibit PelA esterase activity. Cytotoxicity assays using human lung fibroblast cells showed that compound 1 is less cytotoxic than SK-017154-O. This work provides proof of concept that biofilm exopolysaccharide modification enzymes are important for biofilm formation and can serve as useful antibiofilm targets.

}, doi = {10.1128/spectrum.00296-23}, url = {https://journals.asm.org/doi/10.1128/spectrum.00296-23}, author = {Erum Razvi and Benjamin R. DiFrancesco and Gregory A. Wasney and Zachary A. Morrison and John Tam and Anick Auger and Perrin Baker and Noor Alnabelseya and Jacquelyn D. Rich and Piyanka Sivarajah and Gregory B. Whitfield and Joe J. Harrison and Roman A. Melnyk and Mark Nitz and P. Lynne Howell} }