title: Development of metal-chelating inhibitors for the Class II fructose 1,6-bisphosphate (FBP) aldolase.
abstract: It has long been suggested that the essential and ubiquitous enzyme fructose 1,6-bisphosphate (FBP) aldolase could be a good drug target against bacteria and fungi, since lower organisms possess a metal-dependant (Class II) FBP aldolase, as opposed to higher organisms which possess a Schiff-base forming (Class I) FBP aldolase. We have tested the capacity of derivatives of the metal-chelating compound dipicolinic acid (DPA), as well a thiol-containing compound, to inhibit purified recombinant Class II FBP aldolases from Mycobacterium tuberculosis, Pseudomonas aeruginosa, Bacillus cereus, Bacillus anthracis, and from the Rice Blast causative agent Magnaporthe grisea. The aldolase from M. tuberculosis was the most sensitive to the metal-chelating inhibitors, with an IC(50) of 5.2 μM with 2,3-dimercaptopropanesulfonate (DMPS) and 28 μM with DPA. DMPS and the synthesized inhibitor 6-(phosphonomethyl)picolinic acid inhibited the enzyme in a time-dependent, competitive fashion, with second order rate constants of 273 and 270 M(-1) s(-1) respectively for the binding of these compounds to the M. tuberculosis aldolase's active site in the presence of the substrate FBP (K(M) 27.9 μM). The most potent first generation inhibitors were modeled into the active site of the M. tuberculosis aldolase structure, with results indicating that the metal chelators tested cannot bind the catalytic zinc in a bidentate fashion while it remains in its catalytic location, and that most enzyme-ligand interactions involve the phosphate binding pocket residues.
authors.affiliation: Department of Chemistry, University of Waterloo, 200 University Ave. W, Waterloo, ON, Canada N2L 3G1.
authors.forename: Geneviève
authors.initials: G
authors.lastname: Labbé
authors.forename: Anthony P
authors.initials: AP
authors.lastname: Krismanich
authors.forename: Sarah
authors.initials: S
authors.lastname: de Groot
authors.forename: Timothy
authors.initials: T
authors.lastname: Rasmusson
authors.forename: Muhong
authors.initials: M
authors.lastname: Shang
authors.forename: Matthew D R
authors.initials: MD
authors.lastname: Brown
authors.forename: Gary I
authors.initials: GI
authors.lastname: Dmitrienko
authors.forename: J Guy
authors.initials: JG
authors.lastname: Guillemette
mesh_terms: D001665:Binding Sites; D001667:Binding, Competitive; D002614:Chelating Agents / Q000737:chemistry* / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D005634:Fructose-Bisphosphate Aldolase / Q000037:antagonists & inhibitors* / Q000737:chemistry*; D008670:Metals / Q000737:chemistry; D008958:Models, Molecular; D009169:Mycobacterium tuberculosis / Q000201:enzymology; D010848:Picolinic Acids / Q000737:chemistry / Q000494:pharmacology; D011487:Protein Conformation; D013438:Sulfhydryl Compounds / Q000737:chemistry / Q000494:pharmacology; D014494:Unithiol / Q000737:chemistry; D015032:Zinc / Q000737:chemistry
chemical_list: D002614:Chelating Agents; D004791:Enzyme Inhibitors; D008670:Metals; D010848:Picolinic Acids; D013438:Sulfhydryl Compounds; D014494:Unithiol; D005634:Fructose-Bisphosphate Aldolase; D015032:Zinc; C004860:dipicolinic acid