title: Synthesis and evaluation of inhibitors of E. coli PgaB, a polysaccharide de-N-acetylase involved in biofilm formation.
abstract: Many medically important biofilm forming bacteria produce similar polysaccharide intercellular adhesins (PIA) consisting of partially de-N-acetylated β-(1 → 6)-N-acetylglucosamine polymers (dPNAG). In Escherichia coli, de-N-acetylation of the β-(1 → 6)-N-acetylglucosamine polymer (PNAG) is catalysed by the carbohydrate esterase family 4 deacetylase PgaB. The de-N-acetylation of PNAG is essential for productive PNAG-dependent biofilm formation. Here, we describe the development of a fluorogenic assay to monitor PgaB activity in vitro and the synthesis of a series of PgaB inhibitors. The synthesized inhibitors consist of a metal chelating functional group on a glucosamine scaffold to target the active site metal ion of PgaB. Optimal inhibition was observed with N-thioglycolyl amide (K(i) = 480 μM) and N-methyl-N-glycolyl amide (K(i) = 320 μM) glucosamine derivatives. A chemoenzymatic synthesis of an N-thioglycolyl amide PNAG pentasaccharide led to an inhibitor with an improved K(i) of 280 μM.
authors.affiliation: Department of Chemistry, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Anthony
authors.initials: A
authors.lastname: Chibba
authors.forename: Joanna
authors.initials: J
authors.lastname: Poloczek
authors.forename: Dustin J
authors.initials: DJ
authors.lastname: Little
authors.forename: P Lynne
authors.initials: PL
authors.lastname: Howell
authors.forename: Mark
authors.initials: M
authors.lastname: Nitz
mesh_terms: D000117:Acetylglucosamine / Q000378:metabolism; D000581:Amidohydrolases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development*; D020134:Catalytic Domain; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D004926:Escherichia coli / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D004927:Escherichia coli Infections / Q000188:drug therapy; D029968:Escherichia coli Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D005944:Glucosamine / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D006801:Humans
chemical_list: D004791:Enzyme Inhibitors; D029968:Escherichia coli Proteins; D000581:Amidohydrolases; C575184:poly-beta-1,6-N-acetyl-D-glucosamine de-N-acetylase, E coli; D005944:Glucosamine; D000117:Acetylglucosamine