title: Assessment of Mycobacterium tuberculosis pantothenate kinase vulnerability through target knockdown and mechanistically diverse inhibitors.
abstract: Pantothenate kinase (PanK) catalyzes the phosphorylation of pantothenate, the first committed and rate-limiting step toward coenzyme A (CoA) biosynthesis. In our earlier reports, we had established that the type I isoform encoded by the coaA gene is an essential pantothenate kinase in Mycobacterium tuberculosis, and this vital information was then exploited to screen large libraries for identification of mechanistically different classes of PanK inhibitors. The present report summarizes the synthesis and expansion efforts to understand the structure-activity relationships leading to the optimization of enzyme inhibition along with antimycobacterial activity. Additionally, we report the progression of two distinct classes of inhibitors, the triazoles, which are ATP competitors, and the biaryl acetic acids, with a mixed mode of inhibition. Cocrystallization studies provided evidence of these inhibitors binding to the enzyme. This was further substantiated with the biaryl acids having MIC against the wild-type M. tuberculosis strain and the subsequent establishment of a target link with an upshift in MIC in a strain overexpressing PanK. On the other hand, the ATP competitors had cellular activity only in a M. tuberculosis knockdown strain with reduced PanK expression levels. Additionally, in vitro and in vivo survival kinetic studies performed with a M. tuberculosis PanK (MtPanK) knockdown strain indicated that the target levels have to be significantly reduced to bring in growth inhibition. The dual approaches employed here thus established the poor vulnerability of PanK in M. tuberculosis.
authors.affiliation: Department of Chemistry, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: B K Kishore
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authors.lastname: Reddy
authors.affiliation: Department of Chemistry, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: Sudhir
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authors.lastname: Landge
authors.affiliation: Department of Bioscience, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: Sudha
authors.initials: S
authors.lastname: Ravishankar
authors.affiliation: Department of Chemistry, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: Vikas
authors.initials: V
authors.lastname: Patil
authors.affiliation: Department of Chemistry, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: Vikas
authors.initials: V
authors.lastname: Shinde
authors.affiliation: Department of Chemistry, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: Subramanyam
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authors.lastname: Tantry
authors.affiliation: Department of Chemistry, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: Manoj
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authors.lastname: Kale
authors.affiliation: Department of Chemistry, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: Anandkumar
authors.initials: A
authors.lastname: Raichurkar
authors.affiliation: Department of Chemistry, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: Sreenivasaiah
authors.initials: S
authors.lastname: Menasinakai
authors.affiliation: Department of Bioscience, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: Naina Vinay
authors.initials: NV
authors.lastname: Mudugal
authors.affiliation: Department of Bioscience, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: Anisha
authors.initials: A
authors.lastname: Ambady
authors.affiliation: Department of Bioscience, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: Anirban
authors.initials: A
authors.lastname: Ghosh
authors.affiliation: Department of Bioscience, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: Ragadeepthi
authors.initials: R
authors.lastname: Tunduguru
authors.affiliation: Department of Bioscience, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: Parvinder
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authors.lastname: Kaur
authors.affiliation: Cellworks Research India Pvt. Ltd., Bangalore, India.
authors.forename: Ragini
authors.initials: R
authors.lastname: Singh
authors.affiliation: Department of DMPK and Animal Sciences, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: Naveen
authors.initials: N
authors.lastname: Kumar
authors.affiliation: Department of DMPK and Animal Sciences, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: Sowmya
authors.initials: S
authors.lastname: Bharath
authors.affiliation: Department of Bioscience, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: Aishwarya
authors.initials: A
authors.lastname: Sundaram
authors.affiliation: Department of Bioscience, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: Jyothi
authors.initials: J
authors.lastname: Bhat
authors.affiliation: Department of Bioscience, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: Vasan K
authors.initials: VK
authors.lastname: Sambandamurthy
authors.affiliation: Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.
authors.forename: Christofer
authors.initials: C
authors.lastname: Björkelid
authors.affiliation: Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.
authors.forename: T Alwyn
authors.initials: TA
authors.lastname: Jones
authors.affiliation: Department of Bioscience, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: Kaveri
authors.initials: K
authors.lastname: Das
authors.affiliation: Department of Chemistry, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: Balachandra
authors.initials: B
authors.lastname: Bandodkar
authors.affiliation: Department of Chemistry, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: Krishnan
authors.initials: K
authors.lastname: Malolanarasimhan
authors.affiliation: Department of Bioscience, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India.
authors.forename: Kakoli
authors.initials: K
authors.lastname: Mukherjee
authors.affiliation: Department of Bioscience, iMED infection, AstraZeneca India Pvt. Ltd., Bangalore, India vasanthi.ramachandran@astrazeneca.com.
authors.forename: Vasanthi
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mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology*; D015153:Blotting, Western; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D055785:Gene Knockdown Techniques; D006801:Humans; D008826:Microbial Sensitivity Tests; D009163:Mycobacterium bovis / Q000235:genetics; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics; D010641:Phenotype; D010766:Phosphorylation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors* / Q000235:genetics; D011487:Protein Conformation; D015363:Quinolones / Q000494:pharmacology; D013329:Structure-Activity Relationship; D014230:Triazoles / Q000494:pharmacology
chemical_list: D000995:Antitubercular Agents; D004791:Enzyme Inhibitors; D015363:Quinolones; D014230:Triazoles; D017853:Phosphotransferases (Alcohol Group Acceptor); C023088:pantothenate kinase