Loss of a Functionally and Structurally Distinct ld-Transpeptidase, LdtMt5, Compromises Cell Wall Integrity in Mycobacterium tuberculosis

Basta, Leighanne A. Brammer; Ghosh, Anita; Pan, Ying; Jakoncic, Jean; Lloyd, Evan P.; Townsend, Craig A.; Lamichhane, Gyanu; Bianchet, M.A.

doi:10.1074/jbc.m115.660753

Cited by 50 publications

(67 citation statements)

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“…Similarly, loss of the predominant Ldt homologue, Rv2518c ( ldt Mt2 ), was associated with aberrant colony morphology as well as susceptibility to amoxicillin‐clavulanate . Despite the functional and structural similarity of Ldt Mt5 to Ldt Mt2 , which was consistent with our analyses (Table ), mutant strains lacking Ldt Mt5 displayed slower growth relative to the wildtype and increased susceptibility to crystal violet, osmotic shock and certain carbapenem antibiotics . Moreover, strains simultaneously lacking Ldt Mt1 and Ldt Mt2 displayed increased susceptibility to vancomycin .…”

Section: β‐Lactam Resistance Is Mediated In Part By Lmw Pbps and Ldtssupporting

confidence: 84%

β‐lactam resistance: The role of low molecular weight penicillin binding proteins, β‐lactamases and ld‐transpeptidases in bacteria associated with respiratory tract infections

2018

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Disruption of peptidoglycan (PG) biosynthesis in the bacterial cell wall by β-lactam antibiotics has transformed therapeutic options for bacterial infections. These antibiotics target the transpeptidase domains in penicillin binding proteins (PBPs), which can be classified into high and low molecular weight (LMW) counterparts. While the essentiality of the former has been extensively demonstrated, the physiological roles of LMW PBPs remain poorly understood. Herein, we review the function of LMW PBPs, β-lactamases and ld-transpeptidases (Ldts) in pathogens associated with respiratory tract infections. More specifically, we explore their roles in mediating β-lactam resistance. Using a comparative genomics approach, we identified a high degree of genetic redundancy for LMW PBPs which retain the motifs, SxxN, SxN and KTG required for catalytic activity. Differences in domain architecture suggest distinct physiological roles, possibly related to bacterial cell cycle and/or adaptation to various environmental conditions. Many of the LMW PBPs play an important role in β-lactam resistance either through mutation or variation in abundance. In all of the bacterial genomes assessed, at least one β-lactamase homologue is present, suggesting that enzymatic degradation of β-lactams is a highly conserved resistance mechanism. Furthermore, the presence of Ldt homologues in the majority of species surveyed suggests that alternative PG crosslinking may further mediate β-lactam drug resistance. A deeper understanding of the interplay between these different mechanisms of β-lactam resistance will provide a framework for new therapeutics, which are urgently required given the rapid emergence of antimicrobial resistance. © 2018 IUBMB Life, 70(9):855-868, 2018.

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Section: β‐Lactam Resistance Is Mediated In Part By Lmw Pbps and Ldtssupporting

confidence: 84%

β‐lactam resistance: The role of low molecular weight penicillin binding proteins, β‐lactamases and ld‐transpeptidases in bacteria associated with respiratory tract infections

2018

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“…Structures of its paralogs, including apo -Ldt Mt1 and an imipenem-adduct structure of Ldt Mt1 [23], the apo - and meropenem-adduct structures of Ldt Mt5 [15] have also been reported. These data have provided structural and mechanistic insights about this family of enzymes, as well as details about the mechanisms of inactivation by carbapenem antibiotics.…”

Section: Introductionmentioning

confidence: 99%

Structural insight into the inactivation of Mycobacterium tuberculosis non-classical transpeptidase LdtMt2 by biapenem and tebipenem

et al. 2017

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BackgroundThe carbapenem subclass of β-lactams is among the most potent antibiotics available today. Emerging evidence shows that, unlike other subclasses of β-lactams, carbapenems bind to and inhibit non-classical transpeptidases (L,D-transpeptidases) that generate 3 → 3 linkages in bacterial peptidoglycan. The carbapenems biapenem and tebipenem exhibit therapeutically valuable potencies against Mycobacterium tuberculosis (Mtb).ResultsHere, we report the X-ray crystal structures of Mtb L,D-transpeptidase-2 (LdtMt2) complexed with biapenem or tebipenem. Despite significant variations in carbapenem sulfur side chains, biapenem and tebipenem ultimately form an identical adduct that docks to the outer cavity of LdtMt2. We propose that this common adduct is an enzyme catalyzed decomposition of the carbapenem adduct by a mechanism similar to S-conjugate elimination by β-lyases.ConclusionThe results presented here demonstrate biapenem and tebipenem bind to the outer cavity of LdtMt2, covalently inactivate the enzyme, and subsequently degrade via an S-conjugate elimination mechanism. We discuss structure based drug design based on the findings and propose that the S-conjugate elimination can be leveraged to design novel agents to deliver and locally release antimicrobial factors to act synergistically with the carbapenem carrier.Electronic supplementary materialThe online version of this article (doi:10.1186/s12858-017-0082-4) contains supplementary material, which is available to authorized users.

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“…M. tuberculosis has also five l , d ‐transpeptidases (Squeglia, Ruggiero, & Berisio, ). The loss of only LdtMt5 leads to aberrant growth and increased antibiotic susceptibility (Brammer Basta et al, ). Moreover, while the M. tuberculosis genome encodes two glycosyltransferases and four transpeptidases, the absence of the glycosyltransferase RodA and the transpeptidase PbpA affects pathogen survival in granulomas using a guinea pig infection model despite no effect in vitro for growth in the laboratory media (Arora, Chawla, Malakar, Singh, & Nandicoori, ).…”

Section: Redundancy and Specialization Of Pg Enzymes In Intracellularmentioning

confidence: 99%

“…E. coli mutants defective in multiple l , d ‐transpeptidases are viable in the laboratory (Sanders & Pavelka, ). In M. tuberculosis , in which the fraction of l , d (3‐3)‐bridges can reach up to 80% of the total in stationary phase (Lavollay et al, ), the genetic inactivation of l , d ‐transpeptidases or their inhibition by carbapenems result in aberrant shape and growth defects (Brammer Basta et al, ; Maitra et al, ). Inhibition of l , d ‐transpeptidases by carbepenems is currently an intense area of study in drug therapy against tuberculosis (Gokulan & Varughese, ; Squeglia et al, ).…”

Section: Pg Structural Variations and The Control Of Intracellular Grmentioning

confidence: 99%

Building peptidoglycan inside eukaryotic cells: A view from symbiotic and pathogenic bacteria

Portillo

2020

Molecular Microbiology

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The peptidoglycan (PG), as the exoskeleton of most prokaryotes, maintains a defined shape and ensures cell integrity against the high internal turgor pressure. These important roles have attracted researchers to target PG metabolism in order to control bacterial infections. Most studies, however, have been performed in bacteria grown under laboratory conditions, leading to only a partial view on how the PG is synthetized in natural environments. As a case in point, PG metabolism and its regulation remain poorly understood in symbiotic and pathogenic bacteria living inside eukaryotic cells. This review focuses on the PG metabolism of intracellular bacteria, emphasizing the necessity of more in vivo studies involving the analysis of enzymes produced in the intracellular niche and the isolation of PG from bacteria residing within eukaryotic cells. The review also points to persistent infections caused by some intracellular bacterial pathogens and the extent at which the PG could contribute to establish such physiological state. Based on recent evidences, I speculate on the idea that certain structural features of the PG may facilitate attenuation of intracellular growth. Lastly, I discuss recent findings in endosymbionts supporting a cooperation between host and bacterial enzymes to assemble a mature PG.

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Loss of a Functionally and Structurally Distinct ld-Transpeptidase, LdtMt5, Compromises Cell Wall Integrity in Mycobacterium tuberculosis

Abstract: Background: M. tuberculosis

Cited by 50 publications

References 48 publications

β‐lactam resistance: The role of low molecular weight penicillin binding proteins, β‐lactamases and ld‐transpeptidases in bacteria associated with respiratory tract infections

β‐lactam resistance: The role of low molecular weight penicillin binding proteins, β‐lactamases and ld‐transpeptidases in bacteria associated with respiratory tract infections

Structural insight into the inactivation of Mycobacterium tuberculosis non-classical transpeptidase LdtMt2 by biapenem and tebipenem

Building peptidoglycan inside eukaryotic cells: A view from symbiotic and pathogenic bacteria

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