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Fish & Shellfish Immunology Dec 2022Mytilus shows great immune resistance to various bacteria from the living waters, indicating a complex immune recognition mechanism against various microbes....
Mytilus shows great immune resistance to various bacteria from the living waters, indicating a complex immune recognition mechanism against various microbes. Peptidoglycan recognition proteins (PGRPs) play an important role in the defense against invading microbes via the recognition of the immunogenic substance peptidoglycan (PGN). Therefore, eight PGRPs were identified from the gill transcriptome of Mytilus coruscus. The sequence features, expression pattern in various organs and larval development stages, and microbes induced expression profiles of these Mytilus PGRPs were determined. Our data revealed the constitutive expression of PGRPs in various organs with relative higher expression level in immune-related organs. The expression of PGRPs is developmentally regulated, and most PGRPs are undetectable in larvae stages. The expression level of most PGRPs was significantly increased with in vivo microbial challenges, showing strong response to Gram-positive strain in gill and digestive gland, strong response to Gram-negative strain in hemocytes, and relative weaker response to fungus in the three tested organs. In addition, the function analysis of the representative recombinant expressed PGRP (rMcPGRP-2) confirmed the antimicrobial and agglutination activities, showing the immune-related importance of PGRP in Mytilus. Our work suggests that Mytilus PGRPs can act as pattern recognition receptors to recognize the invading microorganisms and the antimicrobial effectors during the innate immune response of Mytilus.
Topics: Animals; Mytilus; Carrier Proteins; Peptidoglycan; Receptors, Pattern Recognition; Immunity, Innate
PubMed: 36272520
DOI: 10.1016/j.fsi.2022.10.018 -
Antimicrobial Agents and Chemotherapy 2014Synthesis of peptidoglycan precursors ending in D-lactate (D-Lac) is thought to be responsible for glycopeptide resistance in members of the order Actinomycetales that...
Synthesis of peptidoglycan precursors ending in D-lactate (D-Lac) is thought to be responsible for glycopeptide resistance in members of the order Actinomycetales that produce these drugs and in related soil bacteria. More recently, the peptidoglycan of several members of the order Actinomycetales was shown to be cross-linked by L,D-transpeptidases that use tetrapeptide acyl donors devoid of the target of glycopeptides. To evaluate the contribution of these resistance mechanisms, we have determined the peptidoglycan structure of Streptomyces coelicolor A(3)2, which harbors a vanHAX gene cluster for the production of precursors ending in D-Lac, and Nonomuraea sp. strain ATCC 39727, which is devoid of vanHAX and produces the glycopeptide A40296. Vancomycin retained residual activity against S. coelicolor A(3)2 despite efficient incorporation of D-Lac into cytoplasmic precursors. This was due to a D,D-transpeptidase-catalyzed reaction that generated a stem pentapeptide recognized by glycopeptides by the exchange of D-Lac for D-Ala and Gly. The contribution of L,D-transpeptidases to resistance was limited by the supply of tetrapeptide acyl donors, which are essential for the formation of peptidoglycan cross-links by these enzymes. In the absence of a cytoplasmic metallo-D,D-carboxypeptidase, the tetrapeptide substrate was generated by hydrolysis of the C-terminal D-Lac residue of the stem pentadepsipeptide in the periplasm in competition with the exchange reaction catalyzed by D,D-transpeptidases. In Nonomuraea sp. strain ATCC 39727, the contribution of L,D-transpeptidases to glycopeptide resistance was limited by the incomplete conversion of pentapeptides into tetrapeptides despite the production of a cytoplasmic metallo-D,D-carboxypeptidase. Since the level of drug production exceeds the level of resistance, we propose that L,D-transpeptidases merely act as a tolerance mechanism in this bacterium.
Topics: Actinomycetales; Anti-Bacterial Agents; Drug Resistance, Bacterial; Glycopeptides; Peptidoglycan; Streptomyces coelicolor
PubMed: 24395229
DOI: 10.1128/AAC.02329-13 -
FEMS Microbiology Letters May 2011Peptidoglycan plays a vital role in bacterial physiology, maintaining cell shape and resisting cellular lysis from high internal turgor pressures. Its integrity is... (Review)
Review
Peptidoglycan plays a vital role in bacterial physiology, maintaining cell shape and resisting cellular lysis from high internal turgor pressures. Its integrity is carefully maintained by controlled remodeling during growth and division by the coordinated activities of penicillin-binding proteins, lytic transglycosylases, and N-acetylmuramyl-l-alanine amidases. However, its small pore size (∼2 nm) and covalently closed structure make it a formidable barrier to the assembly of large macromolecular cell-envelope-spanning complexes involved in motility and secretion. Here, we review the strategies used by Gram-negative bacteria to assemble such macromolecular complexes across the peptidoglycan layer, while preserving its essential structural role. In addition, we discuss evidence that suggests that peptidoglycan can be integrated into cell-envelope-spanning complexes as a structural and functional extension of their architecture.
Topics: Biological Transport; Cell Wall; Gram-Negative Bacteria; Macromolecular Substances; Peptidoglycan
PubMed: 21276045
DOI: 10.1111/j.1574-6968.2011.02228.x -
Cell Reports Apr 2020The bacterial cell wall is made of peptidoglycan (PG), a polymer that is essential for the maintenance of cell shape and survival. During growth, bacteria remodel their...
The bacterial cell wall is made of peptidoglycan (PG), a polymer that is essential for the maintenance of cell shape and survival. During growth, bacteria remodel their PG, releasing fragments that are predominantly re-internalized and recycled. Here, we show that Vibrio cholerae recycles PG fragments modified with non-canonical d-amino acids (NCDAA), which lead to the accumulation of cytosolic PG tetrapeptides. We demonstrate that the accumulation of recycled tetrapeptides has two regulatory consequences for the cell wall: reduction of d,d-cross-linkage and reduction of PG synthesis. We further demonstrate that l,d-carboxypeptidases from five different species show a preferential activity for substrates containing canonical (d-alanine) versus non-canonical (d-methionine) d-amino acids, suggesting that the accumulation of intracellular tetrapeptides in NCDAA-rich environments is widespread. Collectively, this work reveals a regulatory role of NCDAA linking PG recycling and synthesis to promote optimal cell wall assembly and composition in the stationary phase.
Topics: Cell Wall; Peptidoglycan
PubMed: 32348759
DOI: 10.1016/j.celrep.2020.107578 -
Glycobiology Sep 2001The compositional complexity of the mycobacterial cell envelope differentiates Mycobacterium species from most other prokaryotes. Historically, research in this area has... (Review)
Review
The compositional complexity of the mycobacterial cell envelope differentiates Mycobacterium species from most other prokaryotes. Historically, research in this area has focused on the elucidation of the structure of the mycobacterial cell envelope with the result that the structures of the mycolic acid-arabinogalactan-peptidoglycan complex from M. tuberculosis are fairly well understood. However, the current impetus for studying M. tuberculosis and other pathogenic mycobacteria is the need to identify targets for the development of new drugs. Therefore, emphasis has been shifting to the study of cell envelope biosynthesis and the identification of enzymes that are essential to the viability of M. tuberculosis. The publication of the complete M. tuberculosis genome in 1998 has greatly aided these studies. To date, thirteen enzymes involved in the synthesis of the arabinogalactan-peptidoglycan complex of M. tuberculosis have been identified and at least partially characterized. Eleven of these enzymes were reported subsequent to the publication of the M. tuberculosis genome, a clear indication of the rapid evolution of knowledge stimulated by the sequencing of the genome. In this article we review the current understanding of M. tuberculosis arabinogalactan-peptidoglycan structure and biosynthesis.
Topics: Carbohydrate Conformation; Galactans; Mycobacterium tuberculosis; Peptidoglycan
PubMed: 11555614
DOI: 10.1093/glycob/11.9.107r -
Current Opinion in Structural Biology Oct 2013Growth and maintenance of the protective peptidoglycan cell wall are vital to bacterial growth and morphogenesis. Thus, the relative rate and spatiotemporal control of... (Review)
Review
Growth and maintenance of the protective peptidoglycan cell wall are vital to bacterial growth and morphogenesis. Thus, the relative rate and spatiotemporal control of the synthesis and degradation of this net-like polymer defines bacterial cell shape. In recent years, our understanding of the processes that govern this delicate metabolic balance has improved and should lend insight into how to therapeutically target the system in the future.
Topics: Bacteria; Cell Wall; Glycosylation; Peptidoglycan
PubMed: 23910891
DOI: 10.1016/j.sbi.2013.07.008 -
Canadian Journal of Microbiology Feb 1992Bacterial cell walls and their structural units, particularly peptidoglycan, induce a vast variety of biological effects in host organisms. The pathobiological effects... (Comparative Study)
Comparative Study Review
Bacterial cell walls and their structural units, particularly peptidoglycan, induce a vast variety of biological effects in host organisms. The pathobiological effects of peptidoglycan are greatly enhanced by various modifications and substitutions to its basic composition and structure. One such modification is the presence of acetyl moieties at the C-6 hydroxyl group of N-acetylmuramyl residues, and to date, 11 species of eubacteria, including some important human pathogens, such as Neisseria gonorrhoeae, Proteus mirabilis, and Staphylococcus aureus, are known to possess O-acetylated peptidoglycan. This review addresses the influence of O-acetylation of peptidoglycan on its resistance to degradation both in vitro and in vivo, the clinical importance of the modification, and the currently held views on the pathway for its biosynthesis.
Topics: Acetates; Carbohydrate Sequence; Escherichia coli; Glycopeptides; Molecular Sequence Data; Peptidoglycan
PubMed: 1521192
DOI: 10.1139/m92-014 -
Bioorganic Chemistry Aug 2014The lack of novel antimicrobial drugs under development coupled with the increasing occurrence of resistance to existing antibiotics by community and hospital acquired... (Review)
Review
The lack of novel antimicrobial drugs under development coupled with the increasing occurrence of resistance to existing antibiotics by community and hospital acquired infections is of grave concern. The targeting of biosynthesis of the peptidoglycan component of the bacterial cell wall has proven to be clinically valuable but relatively little therapeutic development has been directed towards the transglycosylase step of this process. Advances towards the isolation of new antimicrobials that target transglycosylase activity will rely on the development of the enzymological tools required to identify and characterise novel inhibitors of these enzymes. Therefore, in this article, we review the assay methods developed for transglycosylases and review recent novel chemical inhibitors discovered in relation to both the lipidic substrates and natural product inhibitors of the transglycosylase step.
Topics: Animals; Enzyme Inhibitors; Humans; Peptidoglycan; Peptidoglycan Glycosyltransferase
PubMed: 24924926
DOI: 10.1016/j.bioorg.2014.05.007 -
Journal of Agricultural and Food... Apr 2023Glycine-rich flexible peptide linkers have been widely adopted in fusion protein engineering; however, they can hardly be cleaved for the separation of fusion partners...
Glycine-rich flexible peptide linkers have been widely adopted in fusion protein engineering; however, they can hardly be cleaved for the separation of fusion partners unless specific protease recognition sites are introduced. Herein, we report the use of the peptidoglycan-targeting staphylolytic enzyme lysostaphin to directly digest the glycine-rich flexible linkers of various lengths including oligoglycine linkers and (GS) linkers, without the incorporation of extra amino acids. Using His-MBP-linker-LbCpf1 as a model substrate, we show that both types of linkers could be digested by lysostaphin, and the digestion efficiency improved with increasing linker length. The enzyme LbCpf1 retained full activity after tag removal. We further demonstrated that the proteolytic activity of lysostaphin could be well maintained under different environmental conditions and in the presence of a series of chemical reagents at various concentrations that are frequently used in protein purification and stabilization. In addition, such a digestion strategy could also be applied to remove the SUMO domain linked to LwCas13a via an octaglycine linker. This study extends the applications of lysostaphin beyond an antimicrobial reagent and demonstrates its potential as a novel, efficient, and robust protease for protein engineering.
Topics: Lysostaphin; Peptide Hydrolases; Peptidoglycan; Glycine; Cell Wall
PubMed: 36967580
DOI: 10.1021/acs.jafc.3c00189 -
BMB Reports Feb 2008The major cell wall components of bacteria are lipopolysaccharide, peptidoglycan, and teichoic acid. These molecules are known to trigger strong innate immune responses... (Review)
Review
The major cell wall components of bacteria are lipopolysaccharide, peptidoglycan, and teichoic acid. These molecules are known to trigger strong innate immune responses in the host. The molecular mechanisms by which the host recognizes the peptidoglycan of Gram-positive bacteria and amplifies this peptidoglycan recognition signals to mount an immune response remain largely unclear. Recent, elegant genetic and biochemical studies are revealing details of the molecular recognition mechanism and the signalling pathways triggered by bacterial peptidoglycan. Here we review recent progress in elucidating the molecular details of peptidoglycan recognition and its signalling pathways in insects. We also attempt to evaluate the importance of this issue for understanding innate immunity.
Topics: Animals; Bacteria; Immune System; Immunity, Innate; Insecta; Peptidoglycan; Signal Transduction
PubMed: 18315943
DOI: 10.5483/bmbrep.2008.41.2.093