Identification of Genetic Determinants and Enzymes Involved with the Amidation of Glutamic Acid Residues in the Peptidoglycan of Staphylococcus aureus

Figueiredo, Teresa A.; Ludovice, Ana Madalena; Almeida, João M. G. C. F.; Bui, Nhat Khai; Vollmer, Waldemar; Lencastre, Hermı́nia de; Tomasz, Alexander

doi:10.1371/journal.ppat.1002508

Cited by 92 publications

(117 citation statements)

References 28 publications

(42 reference statements)

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“…It also could result from a change in the ratio between the two types of peptidoglycan cross-links (433 and 333), which had been proposed to influence the flexibility/rigidity of the polymer (50). A similar increase in lysozyme sensitivity was observed with peptidoglycan purified from S. aureus strains in which D-Glu amidation was conditionally expressed and modulated (48). The modification of the peptide charge resulting from the amidation of either of these residues could have a repulsive effect on lysozyme and inhibit the peptidoglycan binding and/or peptidoglycan hydrolyzing activity of this enzyme.…”

Section: Wild Type (Atcc 13032)supporting

confidence: 55%

“…The same increase of cell sensitivity toward these molecules and some defensins was observed when D-Glu amidation was inhibited in Staphylococcus aureus (47,48). In Lactococcus lactis, amidation of interpeptide D-Asp residues was shown to increase cell resistance against the activities of endogenous autolysins, lysozyme and nisin (49).…”

Section: Wild Type (Atcc 13032)mentioning

confidence: 86%

“…Very recently, genes and enzymes involved in peptidoglycan D-Glu amidation were identified in S. aureus (47,48). Two proteins acting in concert and forming a physically stable complex were shown to be required for the latter modification, a glutamine amidotransferase-like protein (GatD) and a Mur ligase homologue (MurT).…”

Section: Wild Type (Atcc 13032)mentioning

confidence: 99%

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Diaminopimelic Acid Amidation in Corynebacteriales

Levefaudes

Patin

Silva

et al. 2015

Journal of Biological Chemistry

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Background: Diaminopimelic acid (DAP) is mainly found in amidated form in cell wall peptidoglycan of Corynebacteriales. Results: Corynebacterium glutamicum ltsA gene product is a glutamine amidotransferase that specifically amidates peptidoglycan lipid intermediates. Conclusion: LtsA accounts for the peptidoglycan structural modification by DAP amidation observed in Corynebacteriales. Significance: Loss of peptidoglycan DAP amidation results in hyper-susceptibility of bacterial cells to lysozyme and ␤-lactam antibiotics.

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Section: Wild Type (Atcc 13032)supporting

confidence: 55%

Section: Wild Type (Atcc 13032)mentioning

confidence: 86%

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Diaminopimelic Acid Amidation in Corynebacteriales

Levefaudes

Patin

Silva

et al. 2015

Journal of Biological Chemistry

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“…Recently, it was shown that the enzyme LtsA is responsible for the amidation of mDAP (46). The amidation of D-Glu is probably performed by Cg0299 and Cg0300, as shown for homologous proteins of Staphylococcus aureus (47,48). Subsequently, Lipid II is translocated across the cell membrane (step 2), where the peptidoglycan polymerization takes place.…”

Section: Discussionmentioning

confidence: 99%

Impact of LytR-CpsA-Psr Proteins on Cell Wall Biosynthesis in Corynebacterium glutamicum

et al. 2016

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Proteins of the LCP (LytR, CpsA, Psr) family have been shown to inherit important roles in bacterial cell wall biosynthesis. However, their exact function in the formation of the complex cell wall structures of the Corynebacteriales, including the prominent pathogens Mycobacterium tuberculosis and Corynebacterium diphtheriae, remains unclear. Here, we analyzed the role of the LCP proteins LcpA and LcpB of Corynebacterium glutamicum, both of which localize at regions of nascent cell wall biosynthesis. A strain lacking lcpB did not show any growth-related or morphological phenotype under the tested conditions. In contrast, conditional silencing of the essential lcpA gene resulted in severe growth defects and drastic morphological changes. Compared to the wild-type cell wall, the cell wall of this mutant contained significantly less mycolic acids and a reduced amount of arabinogalactan. In particular, rhamnose, a specific sugar component of the linker that connects arabinogalactan and peptidoglycan, was decreased. Complementation studies of the lcpA-silencing strain with several mutated and truncated LcpA variants suggested that both periplasmic domains are essential for function whereas the cytoplasmic N-terminal part is dispensable. Successful complementation experiments with proteins of M. tuberculosis and C. diphtheriae revealed a conserved function of LCP proteins in these species. Finally, pyrophosphatase activity of LcpA was shown in an in vitro assay. Taken together, our results suggest that LCP proteins are responsible for the transfer of arabinogalactan onto peptidoglycan in actinobacterial species and support a crucial function of a so-far-uncharacterized C-terminal domain (LytR_C domain) which is frequently found at the C terminus of the LCP domain in this prokaryotic phylum. IMPORTANCEAbout one-third of the world's population is infected with Mycobacterium tuberculosis, and multiple-antibiotic resistance provokes the demand for novel antibiotics. The special cell wall architecture of Corynebacteriales is critical for treatments because it is either a direct target or a barrier that the drug has to cross. Here, we present the analysis of LcpA and LcpB of the closely related Corynebacterium glutamicum, the first of which is an essential protein involved in cell wall biogenesis. Our work provides a comprehensive characterization of the impact of LCP proteins on cell wall biogenesis in this medically and biotechnologically important class of bacteria. Special focus is set on the two periplasmic LcpA domains and their contributions to physiological function.

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“…32 Recently, a small operon, encoding the enzymatic complex MurT-GatD, was identified to be responsible for a secondary modification of peptidoglycan in S. aureus, the amidation of glutamic acid in the stem peptides. 17,34 Inhibition of amidation caused reduced growth rate; reduced resistance to betalactam antibiotics, shown previously to be affected by auxiliary genes 14 ; and increased sensitivity to lysozyme in HA-MRSA strain COL. 17 In this communication we report that peptidoglycan amidation has different impacts in the expression of resistance to beta-lactams and to lysozyme, depending on the genetic background of the particular strain. These observations suggest that S. aureus, from different genetic lineages, include different elements from their core genomes in the strategies of resistance to beta-lactam and lysozyme adopted.…”

mentioning

confidence: 86%

Contribution of Peptidoglycan Amidation to Beta-Lactam and Lysozyme Resistance in Different Genetic Lineages ofStaphylococcus aureus

Figueiredo

Ludovice²

2014

Microbial Drug Resistance

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The enzymes responsible for peptidoglycan amidation in Staphylococcus aureus, MurT and GatD, were recently identified and shown to be required for optimal expression of resistance to beta-lactams, bacterial growth, and resistance to lysozyme. In this study, we analyzed the impact of peptidoglycan amidation in representative strains of the most widespread clones of methicillin resistant S. aureus (MRSA). The inhibition of the expression of murT-gatD operon resulted in different phenotypes of resistance to beta-lactams and lysozyme according to the different genetic backgrounds. Further, clonal lineages CC1 and CC398 (community-acquired MRSA [CA-MRSA]) showed a stronger dependency on MurT-GatD for resistance to beta-lactams, when compared to the impact of the impairment of the cell wall step catalyzed by MurF. In the remaining backgrounds similar phenotypes of beta-lactam resistance were observed upon the impairment of both cell-wall-related genes. Therefore, for CA-related backgrounds, the predominant beta-lactam resistance mechanism seems to involve genes associated with secondary modifications of peptidoglycan. On the other hand, the lack of glutamic acid amidation had a more substantial impact on lysozyme resistance for cells of CA-MRSA backgrounds, than for hospital-acquired MRSA (HA-MRSA). However, no significant differences were found in the resistance level of the respective peptidoglycan structure, suggesting that the lysozyme resistance mechanism involves other factors. Taken together, these results suggested that the different genetic lineages of MRSA were able to develop different molecular strategies to overcome the selective pressures experienced during evolution.

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Identification of Genetic Determinants and Enzymes Involved with the Amidation of Glutamic Acid Residues in the Peptidoglycan of Staphylococcus aureus

Cited by 92 publications

References 28 publications

Diaminopimelic Acid Amidation in Corynebacteriales

Diaminopimelic Acid Amidation in Corynebacteriales

Impact of LytR-CpsA-Psr Proteins on Cell Wall Biosynthesis in Corynebacterium glutamicum

Contribution of Peptidoglycan Amidation to Beta-Lactam and Lysozyme Resistance in Different Genetic Lineages ofStaphylococcus aureus

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