title: Fragment-based design of symmetrical bis-benzimidazoles as selective inhibitors of the trimethoprim-resistant, type II R67 dihydrofolate reductase.
abstract: The continuously increasing use of trimethoprim as a common antibiotic for medical use and for prophylactic application in terrestrial and aquatic animal farming has increased its prevalence in the environment. This has been accompanied by increased drug resistance, generally in the form of alterations in the drug target, dihydrofolate reductase (DHFR). The most highly resistant variants of DHFR are known as type II DHFR, among which R67 DHFR is the most broadly studied variant. We report the first attempt at designing specific inhibitors to this emerging drug target by fragment-based design. The detection of inhibition in R67 DHFR was accompanied by parallel monitoring of the human DHFR, as an assessment of compound selectivity. By those means, small aromatic molecules of 150-250 g/mol (fragments) inhibiting R67 DHFR selectively in the low millimolar range were identified. More complex, symmetrical bis-benzimidazoles and a bis-carboxyphenyl were then assayed as fragment-based leads, which procured selective inhibition of the target in the low micromolar range (K(i) = 2-4 μM). The putative mode of inhibition is discussed according to molecular modeling supported by in vitro tests.
authors.affiliation: Département de Biochimie, Université de Montréal, C.P. 6128, Succ. Centre-ville Montréal, Québec H3C 3J7, Canada.
authors.forename: Dominic
authors.initials: D
authors.lastname: Bastien
authors.forename: Maximilian C C J C
authors.initials: MC
authors.lastname: Ebert
authors.forename: Delphine
authors.initials: D
authors.lastname: Forge
authors.forename: Jacynthe
authors.initials: J
authors.lastname: Toulouse
authors.forename: Natalia
authors.initials: N
authors.lastname: Kadnikova
authors.forename: Florent
authors.initials: F
authors.lastname: Perron
authors.forename: Annie
authors.initials: A
authors.lastname: Mayence
authors.forename: Tien L
authors.initials: TL
authors.lastname: Huang
authors.forename: Jean Jacques
authors.initials: JJ
authors.lastname: Vanden Eynde
authors.forename: Joelle N
authors.initials: JN
authors.lastname: Pelletier
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D001562:Benzimidazoles / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D020134:Catalytic Domain; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D015195:Drug Design; D024881:Drug Resistance, Bacterial; D057075:Enzyme Assays; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects; D005493:Folic Acid Antagonists / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D051379:Mice; D008958:Models, Molecular; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry; D013329:Structure-Activity Relationship; D013762:Tetrahydrofolate Dehydrogenase / Q000737:chemistry* / Q000378:metabolism; D014295:Trimethoprim / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001562:Benzimidazoles; D005493:Folic Acid Antagonists; D011994:Recombinant Proteins; D014295:Trimethoprim; C098921:dihydrofolate reductase type II; D013762:Tetrahydrofolate Dehydrogenase