Non-classical transpeptidases yield insight into new antibacterials

Kumar, Priyanka; Kaushik, Amit; Lloyd, Evan P.; Li, Shao Gang; Mattoo, Rohini; Ammerman, Nicole C.; Bell, Drew T.; Perryman, Alexander L.; Zandi, Trevor A.; Ekins, Sean; Ginell, Stephan L.; Townsend, Craig A.; Freundlich, Joel S.; Lamichhane, Gyanu

doi:10.1038/nchembio.2237

Cited by 116 publications

(218 citation statements)

References 47 publications

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“…) and subsequently captured in the crystal structure of Ldt Mt2 (Figs and ). The same fragment was observed from the recent investigation of the homolog Ldt Mt1 suggesting a general mechanism of faropenem action. We show here that the formation of this small adduct derived from faropenem is dependent on a functional enzyme active site, since the H336A mutant displayed a decrease in the faropenem‐driven acylation reaction by several orders of magnitude.…”

Section: Discussionsupporting

confidence: 78%

Binding and processing of β‐lactam antibiotics by the transpeptidase Ldt_Mt2 from Mycobacterium tuberculosis

2017

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b-lactam antibiotics represent a novel direction in the chemotherapy of tuberculosis that brings the peptidoglycan layer of the complex mycobacterial cell wall in focus as a therapeutic target. Peptidoglycan stability in Mycobacterium tuberculosis, especially during infection, relies on the nonconventional peptide cross-links formed by L,D-transpeptidases. These enzymes are known to be inhibited by b-lactams, primarily carbapenems, leading to a stable covalent modification at the enzyme active site. A panel of 16 b-lactam antibiotics was characterized by inhibition kinetics, mass spectrometry, and x-ray crystallography to identify efficient compounds and study their action on the essential transpeptidase, Ldt Mt2 . Members of the carbapenem class displayed fast binding kinetics, but faropenem, a penem type compound showed a three to four time higher rate in the adduct formation. In three cases, mass spectrometry indicated that carbapenems may undergo decarboxylation, while faropenem decomposition following the acylation step results in a small 87 Da b-OH-butyryl adduct bound at the catalytic cysteine residue. The crystal structure of Ldt Mt2 at 1.54A resolution with this fragment bound revealed that the protein adopts a closed conformation that shields the thioester bond from the solvent, which is in line with the high stability of this dead-end complex observed also in biochemical assays.

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Section: Discussionsupporting

confidence: 78%

Binding and processing of β‐lactam antibiotics by the transpeptidase Ldt_Mt2 from Mycobacterium tuberculosis

2017

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“…Correspondingly, in bacteria numerous examples exist of amidation within biosynthetic pathways, including for example peptidoglycan biosynthesis [56, 57]. Thus, it should not be surprising that xenobiotics with the requisite chemical functionality (amine, carboxylic acid, etc.)…”

Section: Biotransformation Of Xenobiotics By M Tuberculosismentioning

confidence: 99%

Antimycobacterial Metabolism: Illuminating Mycobacterium tuberculosis Biology and Drug Discovery

Awasthi

Freundlich

2017

Trends in Microbiology

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Bacteria are capable of performing a number of biotransformations that may activate or deactivate xenobiotics. Recent efforts have utilized metabolomics techniques to study the fate of small molecule antibacterials within the targeted organism. Examples involving Mycobacterium tuberculosis are reviewed and analyzed with regard to the insights they provide as to both activation and deactivation of the antibacterial. The studies, in particular, shed light on biosynthetic transformations performed by M. tuberculosis while suggesting avenues for the evolution of chemical tools, highlighting potential areas for drug discovery, and mechanisms of approved drugs. A two–pronged approach investigating the metabolism of antibacterials within both the host and bacterium is outlined and will be of value to both the chemical biology and drug discovery fields.

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“…β-lactams derive their activity by preventing formation of linkage between peptide side chains by inhibiting the transpeptidases that catalyze this reaction [8]. Recently it was demon strated that majority of the linkages in the peptidoglycan layer of M. abscessus are generated by LD-transpeptidases [9] and that this class of enzyme is selectively more susceptible to the carbapenem class of β-lactams [10][11][12]. Imipenem, a carbapenem, has superior activity compared with ShORt COMMuniCAtiOn Kaushik, Gupta, Fisher et al future science group cefoxitin against clinical strains of M. abscessus isolated from cystic fibrosis patients [13].…”

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confidence: 99%

Combinations of Avibactam and Carbapenems Exhibit Enhanced Potencies Against Drug-Resistant Mycobacterium Abscessus

et al. 2017

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Aim:The objective of this study was to assess if avibactam, a new β-lactamase inhibitor, can restore the potency of carbapenems, a sub-class of β-lactams, against Mycobacterium abscessus clinical isolates. Materials & methods: 28 M. abscessus clinical isolates that are resistant to multiple drugs currently used to treat its infection were included. MIC of carbapenems alone and in combination with avibactam against these strains were determined. Results: Tebipenem, an oral carbapenem, and ertapenem and panipenem exhibited the greatest shift in MIC when supplemented with avibactam. Conclusion: Avibactam restores MICs of tebipenem, ertapenem and panipenem against M. abscessus to therapeutically achievable concentrations and raises the possibility of usefulness of these carbapenems to treat drug-resistant M. abscessus infections. Mycobacterium abscessus is a rapidly growing nontuberculous mycobacterium found widely in soil and water and can cause a spectrum of infections [1]. Prevalence of M. abscessus infections in the lungs of people with chronic conditions, such as cystic fibrosis is significant and can often lead to serious morbidity [2]. A survey revealed that M. abscessus is present in the sputum of approximately 13% of cystic fibrosis patients in the USA [3]. Among nontuberculous mycobacterium lung infections, M. abscessus is one of the prevalent species and often leads to a chronic and incurable disease [4][5][6]. Drug resistance in M. abscessus is steadily rising globally, making it increasingly difficult to manage infections with these strains [7]. Therefore, new drugs and novel regimens are acutely needed to treat infections with M. abscessus. An ideal new drug would inhibit a novel target so that it can be effective against M. abscessus strains that are resistant to currently used drugs.The peptidoglycan is an Achilles' heel of bacteria as agents that inhibit its biosynthesis, namely β-lactams and glycopeptides, comprise some of the most widely used class of antibacterials in modern medicine. β-lactams derive their activity by preventing formation of linkage between peptide side chains by inhibiting the transpeptidases that catalyze this reaction [8]. Recently it was demon strated that majority of the linkages in the peptidoglycan layer of M. abscessus are generated by LD-transpeptidases [9] and that this class of enzyme is selectively more susceptible to the carbapenem class of β-lactams [10][11][12]. Imipenem, a carbapenem, has superior activity compared with For reprint orders, please contact: reprints@futuremedicine.com

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Non-classical transpeptidases yield insight into new antibacterials

Cited by 116 publications

References 47 publications

Binding and processing of β‐lactam antibiotics by the transpeptidase Ldt_Mt2 from Mycobacterium tuberculosis

Binding and processing of β‐lactam antibiotics by the transpeptidase Ldt_Mt2 from Mycobacterium tuberculosis

Antimycobacterial Metabolism: Illuminating Mycobacterium tuberculosis Biology and Drug Discovery

Combinations of Avibactam and Carbapenems Exhibit Enhanced Potencies Against Drug-Resistant Mycobacterium Abscessus

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Non-classical transpeptidases yield insight into new antibacterials

Cited by 116 publications

References 47 publications

Binding and processing of β‐lactam antibiotics by the transpeptidase LdtMt2 from Mycobacterium tuberculosis

Binding and processing of β‐lactam antibiotics by the transpeptidase LdtMt2 from Mycobacterium tuberculosis

Antimycobacterial Metabolism: Illuminating Mycobacterium tuberculosis Biology and Drug Discovery

Combinations of Avibactam and Carbapenems Exhibit Enhanced Potencies Against Drug-Resistant Mycobacterium Abscessus

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Binding and processing of β‐lactam antibiotics by the transpeptidase Ldt_Mt2 from Mycobacterium tuberculosis

Binding and processing of β‐lactam antibiotics by the transpeptidase Ldt_Mt2 from Mycobacterium tuberculosis