title: Pyrazolopyrimidines establish MurC as a vulnerable target in Pseudomonas aeruginosa and Escherichia coli.
abstract: The bacterial peptidoglycan biosynthesis pathway provides multiple targets for antibacterials, as proven by the clinical success of β-lactam and glycopeptide classes of antibiotics. The Mur ligases play an essential role in the biosynthesis of the peptidoglycan building block, N-acetyl-muramic acid-pentapeptide. MurC, the first of four Mur ligases, ligates l-alanine to UDP-N-acetylmuramic acid, initiating the synthesis of pentapeptide precursor. Therefore, inhibiting the MurC enzyme should result in bacterial cell death. Herein, we report a novel class of pyrazolopyrimidines with subnanomolar potency against both Escherichia coli and Pseudomonas aeruginosa MurC enzymes, which demonstrates a concomitant bactericidal activity against efflux-deficient strains. Radio-labeled precursor incorporation showed these compounds selectively inhibited peptidoglycan biosynthesis, and genetic studies confirmed the target of pyrazolopyrimidines to be MurC. In the presence of permeability enhancers such as colistin, pyrazolopyrimidines exhibited low micromolar MIC against the wild-type bacteria, thereby, indicating permeability and efflux as major challenges for this chemical series. Our studies provide biochemical and genetic evidence to support the essentiality of MurC and serve to validate the attractiveness of target for antibacterial discovery.
authors.affiliation: Innovative Medicines, AstraZeneca India Pvt. Ltd., Bellary Road, Hebbal, Bangalore 560024, India.
authors.forename: Shahul
authors.initials: S
authors.lastname: Hameed P
authors.forename: Praveena
authors.initials: P
authors.lastname: Manjrekar
authors.forename: Murugan
authors.initials: M
authors.lastname: Chinnapattu
authors.forename: Vaishali
authors.initials: V
authors.lastname: Humnabadkar
authors.forename: Gajanan
authors.initials: G
authors.lastname: Shanbhag
authors.forename: Chaitanyakumar
authors.initials: C
authors.lastname: Kedari
authors.forename: Naina Vinay
authors.initials: NV
authors.lastname: Mudugal
authors.forename: Anisha
authors.initials: A
authors.lastname: Ambady
authors.forename: Boudewijn L M
authors.initials: BL
authors.lastname: de Jonge
authors.forename: Claire
authors.initials: C
authors.lastname: Sadler
authors.forename: Beena
authors.initials: B
authors.lastname: Paul
authors.forename: Shubha
authors.initials: S
authors.lastname: Sriram
authors.forename: Parvinder
authors.initials: P
authors.lastname: Kaur
authors.forename: Supreeth
authors.initials: S
authors.lastname: Guptha
authors.forename: Anandkumar
authors.initials: A
authors.lastname: Raichurkar
authors.forename: Paul
authors.initials: P
authors.lastname: Fleming
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Eyermann
authors.forename: David C
authors.initials: DC
authors.lastname: McKinney
authors.forename: Vasan K
authors.initials: VK
authors.lastname: Sambandamurthy
authors.forename: Manoranjan
authors.initials: M
authors.lastname: Panda
authors.forename: Sudha
authors.initials: S
authors.lastname: Ravishankar
mesh_terms: D000409:Alanine / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D008956:Models, Chemical; D015394:Molecular Structure; D010453:Peptide Synthases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011494:Protein Kinases / Q000737:chemistry; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000201:enzymology*; D011720:Pyrazoles / Q000494:pharmacology*; D011743:Pyrimidines / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D014538:Uridine Diphosphate N-Acetylmuramic Acid / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D004791:Enzyme Inhibitors; D011720:Pyrazoles; D011743:Pyrimidines; D014538:Uridine Diphosphate N-Acetylmuramic Acid; C014175:pyrazolo(3,4-d)pyrimidine; D011494:Protein Kinases; D010453:Peptide Synthases; C023229:UDP-N-acetylmuramoyl-alanine synthetase; D000409:Alanine