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Nature Communications Jun 2023Secreted proteins are one of the direct molecular mechanisms by which microbiota influence the host, thus constituting a promising field for drug discovery. Here,...
Secreted proteins are one of the direct molecular mechanisms by which microbiota influence the host, thus constituting a promising field for drug discovery. Here, through bioinformatics-guided screening of the secretome of clinically established probiotics from Lactobacillus, we identify an uncharacterized secreted protein (named LPH here) that is shared by most of these probiotic strains (8/10) and demonstrate that it protects female mice from colitis in multiple models. Functional studies show that LPH is a bi-functional peptidoglycan hydrolase with both N-Acetyl-β-D-muramidase and DL-endopeptidase activities that can generate muramyl dipeptide (MDP), a NOD2 ligand. Different active site mutants of LPH in combination with Nod2 knockout female mice confirm that LPH exerts anti-colitis effects through MDP-NOD2 signaling. Furthermore, we validate that LPH can also exert protective effects on inflammation-associated colorectal cancer in female mice. Our study reports a probiotic enzyme that enhances NOD2 signaling in vivo in female mice and describes a molecular mechanism that may contribute to the effects of traditional Lactobacillus probiotics.
Topics: Mice; Female; Animals; Ligands; N-Acetylmuramoyl-L-alanine Amidase; Acetylmuramyl-Alanyl-Isoglutamine; Colitis; Mice, Knockout; Probiotics; Nod2 Signaling Adaptor Protein; Peptidoglycan
PubMed: 37286542
DOI: 10.1038/s41467-023-38950-3 -
Current Issues in Molecular Biology 2021The cell wall of is a rigid structure on the outside of the cell that forms the first barrier between the bacterium and the environment, and at the same time maintains... (Review)
Review
The cell wall of is a rigid structure on the outside of the cell that forms the first barrier between the bacterium and the environment, and at the same time maintains cell shape and withstands the pressure generated by the cell's turgor. In this review, the chemical composition of peptidoglycan, teichoic and teichuronic acids, the polymers that comprise the cell wall, and the biosynthetic pathways involved in their synthesis will be discussed, as well as the architecture of the cell wall. has been the first bacterium for which the role of an actin-like cytoskeleton in cell shape determination and peptidoglycan synthesis was identified and for which the entire set of peptidoglycan synthesizing enzymes has been localised. The role of the cytoskeleton in shape generation and maintenance will be discussed and results from other model organisms will be compared to what is known for . Finally, outstanding questions in the field of cell wall synthesis will be discussed.
Topics: Bacillus subtilis; Biosynthetic Pathways; Cell Wall; Cytoskeleton; Peptidoglycan; Uronic Acids
PubMed: 33048060
DOI: 10.21775/cimb.041.539 -
Nature Jan 2023The microbial cell wall is essential for maintenance of cell shape and resistance to external stressors. The primary structural component of the cell wall is...
The microbial cell wall is essential for maintenance of cell shape and resistance to external stressors. The primary structural component of the cell wall is peptidoglycan, a glycopolymer with peptide crosslinks located outside of the cell membrane. Peptidoglycan biosynthesis and structure are responsive to shifting environmental conditions such as pH and salinity, but the mechanisms underlying such adaptations are incompletely understood. Precursors of peptidoglycan and other cell surface glycopolymers are synthesized in the cytoplasm and then delivered across the cell membrane bound to the recyclable lipid carrier undecaprenyl phosphate (C55-P, also known as UndP). Here we identify the DUF368-containing and DedA transmembrane protein families as candidate C55-P translocases, filling a critical gap in knowledge of the proteins required for the biogenesis of microbial cell surface polymers. Gram-negative and Gram-positive bacteria lacking their cognate DUF368-containing protein exhibited alkaline-dependent cell wall and viability defects, along with increased cell surface C55-P levels. pH-dependent synthetic genetic interactions between DUF368-containing proteins and DedA family members suggest that C55-P transporter usage is dynamic and modulated by environmental inputs. C55-P transporter activity was required by the cholera pathogen for growth and cell shape maintenance in the intestine. We propose that conditional transporter reliance provides resilience in lipid carrier recycling, bolstering microbial fitness both inside and outside the host.
Topics: Bacterial Proteins; Carrier Proteins; Cell Membrane; Cell Wall; Genetic Fitness; Lipids; Peptidoglycan; Polyisoprenyl Phosphates; Gram-Negative Bacteria; Gram-Positive Bacteria; Microbial Viability
PubMed: 36450355
DOI: 10.1038/s41586-022-05569-1 -
Annual Review of Microbiology Oct 2021Most bacteria are protected from environmental offenses by a cell wall consisting of strong yet elastic peptidoglycan. The cell wall is essential for preserving... (Review)
Review
Most bacteria are protected from environmental offenses by a cell wall consisting of strong yet elastic peptidoglycan. The cell wall is essential for preserving bacterial morphology and viability, and thus the enzymes involved in the production and turnover of peptidoglycan have become preferred targets for many of our most successful antibiotics. In the past decades, , the gram-negative pathogen causing the diarrheal disease cholera, has become a major model for understanding cell wall genetics, biochemistry, and physiology. More than 100 articles have shed light on novel cell wall genetic determinants, regulatory links, and adaptive mechanisms. Here we provide the first comprehensive review of 's cell wall biology and genetics. Special emphasis is placed on the similarities and differences with , the paradigm for understanding cell wall metabolism and chemical structure in gram-negative bacteria.
Topics: Biology; Cell Wall; Escherichia coli; Peptidoglycan; Vibrio cholerae
PubMed: 34623898
DOI: 10.1146/annurev-micro-040621-122027 -
Biomolecules Apr 2023Bacteria must synthesize their cell wall and membrane during their cell cycle, with peptidoglycan being the primary component of the cell wall in most bacteria.... (Review)
Review
Bacteria must synthesize their cell wall and membrane during their cell cycle, with peptidoglycan being the primary component of the cell wall in most bacteria. Peptidoglycan is a three-dimensional polymer that enables bacteria to resist cytoplasmic osmotic pressure, maintain their cell shape and protect themselves from environmental threats. Numerous antibiotics that are currently used target enzymes involved in the synthesis of the cell wall, particularly peptidoglycan synthases. In this review, we highlight recent progress in our understanding of peptidoglycan synthesis, remodeling, repair, and regulation in two model bacteria: the Gram-negative and the Gram-positive . By summarizing the latest findings in this field, we hope to provide a comprehensive overview of peptidoglycan biology, which is critical for our understanding of bacterial adaptation and antibiotic resistance.
Topics: Peptidoglycan; Bacteria; Anti-Bacterial Agents; Cell Division; Cell Wall; Bacterial Proteins
PubMed: 37238589
DOI: 10.3390/biom13050720 -
Nature Communications Oct 2023Peptidoglycan, a gigadalton polymer, functions as the scaffold for bacterial cell walls and provides cell integrity. Peptidoglycan is remodelled by a large and diverse...
Peptidoglycan, a gigadalton polymer, functions as the scaffold for bacterial cell walls and provides cell integrity. Peptidoglycan is remodelled by a large and diverse group of peptidoglycan hydrolases, which control bacterial cell growth and division. Over the years, many studies have focused on these enzymes, but knowledge on their action within peptidoglycan mesh from a molecular basis is scarce. Here, we provide structural insights into the interaction between short peptidoglycan fragments and the entire sacculus with two evolutionarily related peptidases of the M23 family, lysostaphin and LytM. Through nuclear magnetic resonance, mass spectrometry, information-driven modelling, site-directed mutagenesis and biochemical approaches, we propose a model in which peptidoglycan cross-linking affects the activity, selectivity and specificity of these two structurally related enzymes differently.
Topics: Humans; Staphylococcus aureus; Peptidoglycan; Hydrolases; Lysostaphin; Mass Spectrometry; Staphylococcal Infections; Cell Wall
PubMed: 37872144
DOI: 10.1038/s41467-023-42506-w -
Critical Reviews in Microbiology Nov 2020The spread of bacterial strains resistant to commonly used antibiotics urges the development of novel antibacterial compounds. Ideally, these novel antimicrobials should... (Review)
Review
The spread of bacterial strains resistant to commonly used antibiotics urges the development of novel antibacterial compounds. Ideally, these novel antimicrobials should be less prone to the development of resistance. Peptidoglycan-degrading enzymes are a promising class of compounds with a fundamentally different mode of action compared to traditionally used antibiotics. The difference in the mechanism of action implies differences both in the mechanisms of resistance and the chances of its emergence. To critically assess the potential of resistance development to peptidoglycan-degrading enzymes, we review the available evidence for the development of resistance to these enzymes , along with the known mechanisms of resistance to lysozyme, bacteriocins, autolysins, and phage endolysins. We conclude that genetic determinants of resistance to peptidoglycan-degrading enzymes are unlikely to readily emerge However, resistance to these enzymes would probably spread by the horizontal transfer between intrinsically resistant and susceptible species. Finally, we speculate that the higher cost of the therapeutics based on peptidoglycan degrading enzymes compared to classical antibiotics might result in less misuse, which in turn would lead to lower selective pressure, making these antibacterials less prone to resistance development.
Topics: Animals; Anti-Bacterial Agents; Bacteria; Bacterial Infections; Bacteriophages; Drug Resistance, Bacterial; Enzymes; Humans; Peptidoglycan
PubMed: 32985279
DOI: 10.1080/1040841X.2020.1825333 -
International Journal of Molecular... Apr 2023The cell envelope of Gram-negative bacteria contains two distinct membranes, an inner (IM) and an outer (OM) membrane, separated by the periplasm, a hydrophilic...
The cell envelope of Gram-negative bacteria contains two distinct membranes, an inner (IM) and an outer (OM) membrane, separated by the periplasm, a hydrophilic compartment that includes a thin layer of peptidoglycan [...].
Topics: Lipopolysaccharides; Bacterial Outer Membrane Proteins; Cell Membrane; Periplasm; Cell Wall; Peptidoglycan
PubMed: 37108660
DOI: 10.3390/ijms24087498 -
Journal of Bacteriology Mar 2023Most bacteria have cell wall peptidoglycan surrounding their plasma membranes. The essential cell wall provides a scaffold for the envelope, protection against turgor... (Review)
Review
Most bacteria have cell wall peptidoglycan surrounding their plasma membranes. The essential cell wall provides a scaffold for the envelope, protection against turgor pressure and is a proven drug target. Synthesis of the cell wall involves reactions that span cytoplasmic and periplasmic compartments. Bacteria carry out the last steps of cell wall synthesis along their plasma membrane. The plasma membrane in bacteria is heterogeneous and contains membrane compartments. Here, I outline findings that highlight the emerging notion that plasma membrane compartments and the cell wall peptidoglycan are functionally intertwined. I start by providing models of cell wall synthesis compartmentalization within the plasma membrane in mycobacteria, Escherichia coli, and Bacillus subtilis. Then, I revisit literature that supports a role for the plasma membrane and its lipids in modulating enzymatic reactions that synthesize cell wall precursors. I also elaborate on what is known about bacterial lateral organization of the plasma membrane and the mechanisms by which organization is established and maintained. Finally, I discuss the implications of cell wall partitioning in bacteria and highlight how targeting plasma membrane compartmentalization serves as a way to disrupt cell wall synthesis in diverse species.
Topics: Peptidoglycan; Feedback; Cell Membrane; Cell Wall; Bacteria; Escherichia coli
PubMed: 36794934
DOI: 10.1128/jb.00433-22 -
Nature Communications Jun 2023The bacterial cell envelope consists of multiple layers, including the peptidoglycan cell wall, one or two membranes, and often an external layer composed of capsular...
The bacterial cell envelope consists of multiple layers, including the peptidoglycan cell wall, one or two membranes, and often an external layer composed of capsular polysaccharides (CPS) or other components. How the synthesis of all these layers is precisely coordinated remains unclear. Here, we identify a mechanism that coordinates the synthesis of CPS and peptidoglycan in Streptococcus pneumoniae. We show that CPS synthesis initiates from the division septum and propagates along the long axis of the cell, organized by the tyrosine kinase system CpsCD. CpsC and the rest of the CPS synthesis complex are recruited to the septum by proteins associated with the divisome (a complex involved in septal peptidoglycan synthesis) but not the elongasome (involved in peripheral peptidoglycan synthesis). Assembly of the CPS complex starts with CpsCD, then CpsA and CpsH, the glycosyltransferases, and finally CpsJ. Remarkably, targeting CpsC to the cell pole is sufficient to reposition CPS synthesis, leading to diplococci that lack CPS at the septum. We propose that septal CPS synthesis is important for chain formation and complement evasion, thereby promoting bacterial survival inside the host.
Topics: Streptococcus pneumoniae; Peptidoglycan; Bacterial Proteins; Polysaccharides; Cell Membrane; Bacterial Capsules; Polysaccharides, Bacterial
PubMed: 37264013
DOI: 10.1038/s41467-023-38904-9