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Bioscience, Biotechnology, and... May 2024In bacteria, d-amino acids are primarily synthesized from l-amino acids by amino acid racemases, but some bacteria use d-amino acid aminotransferases to synthesize... (Review)
Review
In bacteria, d-amino acids are primarily synthesized from l-amino acids by amino acid racemases, but some bacteria use d-amino acid aminotransferases to synthesize d-amino acids. d-Amino acids are peptidoglycan components in the cell wall involved in several physiological processes, such as bacterial growth, biofilm dispersal, and peptidoglycan metabolism. Therefore, their metabolism and physiological roles have attracted increasing attention. Recently, we identified novel bacterial d-amino acid metabolic pathways, which involve amino acid racemases, with broad substrate specificity, as well as multifunctional enzymes with d-amino acid-metabolizing activity. Here, I review these multifunctional enzymes and their related d- and l-amino acid metabolic pathways in Escherichia coli and the hyperthermophile Thermotoga maritima.
Topics: Amino Acids; Thermotoga maritima; Escherichia coli; Substrate Specificity; Amino Acid Isomerases; Peptidoglycan; Transaminases; Bacterial Proteins
PubMed: 38439669
DOI: 10.1093/bbb/zbae027 -
Current Biology : CB Oct 2020A peptidoglycan (PG) cell wall is an essential component of nearly all bacteria, providing protection against turgor pressure. Metabolism of this PG meshwork must be... (Review)
Review
A peptidoglycan (PG) cell wall is an essential component of nearly all bacteria, providing protection against turgor pressure. Metabolism of this PG meshwork must be spatially and temporally regulated in order to support cell growth and division. Despite being an active area of research for decades, we have only recently identified the primary PG synthesis complexes that function during cell elongation (RodA-PBP2) and cell division (FtsW-FtsI), and we are still uncovering the importance of the other seemingly redundant cell wall enzymes. In this minireview, we highlight the discovery of the monofunctional glycosyltransferases RodA and FtsW and describe how these findings have prompted a re-evaluation of the auxiliary role of the bifunctional class A penicillin-binding proteins (aPBPs) as well as the L,D-transpeptidases (LDTs). Specifically, recent work indicates that the aPBPs and LDTs function independently of the primary morphogenetic complexes to support growth, provide protection from stresses, mediate morphogenesis, and/or allow adaptation to different growth conditions. These paradigm-shifting studies have reframed our understanding of bacterial cell wall metabolism, which will only become more refined as emerging technology allows us to tackle the remaining questions surrounding PG biosynthesis.
Topics: Bacteria; Bacterial Proteins; Cell Cycle; Cell Division; Cell Wall; Glycosyltransferases; Membrane Proteins; Penicillin-Binding Proteins; Peptidoglycan
PubMed: 33022262
DOI: 10.1016/j.cub.2020.07.004 -
Food & Function Mar 2022As a broadly defined member of lactic acid bacteria (LAB), the Lactobacillus strain is well characterized in food fermentation and specific strains can enhance the... (Review)
Review
As a broadly defined member of lactic acid bacteria (LAB), the Lactobacillus strain is well characterized in food fermentation and specific strains can enhance the intestinal barrier function and be recognized as the probiotic strain. In recent years, many molecules of the cell surface are thought to be related to the adhesion property in the gastrointestinal mucosa. Mucus layer-related proteins, extracellular matrix proteins, and immunoglobulins also exhibit immunity regulation and protection of the intestinal epithelial barrier function. Meanwhile, the effects of bile and the low pH of the gastrointestinal tract (GIT) on Lactobacillus colonization are also needed to be considered. Furthermore, LAB can adhere and aggregate in the GIT to promote the maturity of biofilm and the extracellular matrix secreting through the signal molecules in the quorum sensing (QS) system. Therefore, it is of great interest to use the QS system to regulate the initial adhesion ability of Lactobacillus and further enhance the probiotic effect of the biofilm formation of beneficial bacteria. This review summarizes the adhesion properties of cell surface proteins derived from Lactobacillus strains in recent studies and provides valuable information on the QS effect on the adhesion property of Lactobacillus strains in the GIT environment.
Topics: Bacterial Adhesion; Bacterial Proteins; Fimbriae, Bacterial; Flagella; Gastrointestinal Tract; Humans; Lactobacillales; Lactobacillus; Membrane Glycoproteins; Membrane Proteins; Mucus; Peptidoglycan; Probiotics; Quorum Sensing; Teichoic Acids
PubMed: 35226005
DOI: 10.1039/d1fo04328e -
Applied Microbiology and Biotechnology Oct 2022Peptidoglycan-degrading enzymes are a group of proteins intensively studied as novel antibacterials, with some of them having reached pre-clinical and clinical stages of...
Peptidoglycan-degrading enzymes are a group of proteins intensively studied as novel antibacterials, with some of them having reached pre-clinical and clinical stages of research. Many peptidoglycan-degrading enzymes have modular organization and consist of a catalytic and a cell wall binding domain. This property has been exploited in enzyme engineering efforts, and many new peptidoglycan-degrading enzymes were generated through domain exchange. However, rational combination of domains from different enzymes is still challenging since relative contribution of every domain to the cumulative bacteriolytic activity is not yet clearly understood. In this work, we investigated the influence of ionic strength and pH on the catalytic efficiency and cell binding of peptidoglycan-degrading enzyme lysostaphin and how this influence is reflected in the lysostaphin bacteriolytic activity. Contrary to generally accepted view, lysostaphin domains are not completely independent and their combination within one protein leads to increased bacteriolytic activity with increasing NaCl concentration, despite both catalysis and cell binding being inhibited by NaCl. This effect is likely mediated by changes in conformation of bacterial cell wall peptidoglycan rather than the physical inter-domain interaction. KEY POINTS: • NaCl enhances bacteriolytic activity of lysostaphin but not of its catalytic domain. • Catalytic activity and cell binding of lysostaphin are inhibited by NaCl. • Peptidoglycan conformation likely affects lysostaphin bacteriolytic activity.
Topics: Catalysis; Cell Wall; Hydrogen-Ion Concentration; Lysostaphin; Peptidoglycan; Sodium Chloride; Staphylococcus aureus
PubMed: 36112205
DOI: 10.1007/s00253-022-12173-w -
Molecular Microbiology Mar 2020The peptidoglycan (PG), as the exoskeleton of most prokaryotes, maintains a defined shape and ensures cell integrity against the high internal turgor pressure. These... (Review)
Review
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.
Topics: Bacteria; Bacterial Infections; Bacterial Proteins; Cell Wall; Eukaryotic Cells; Host-Pathogen Interactions; Humans; Peptidoglycan; Symbiosis; Virulence
PubMed: 32185832
DOI: 10.1111/mmi.14452 -
Bulletin of Experimental Biology and... Dec 2021We studied the effect of bacterial wall peptidoglycan of 7 bacterial species on the competitive properties of human-associated microorganisms. Addition of peptidoglycan...
We studied the effect of bacterial wall peptidoglycan of 7 bacterial species on the competitive properties of human-associated microorganisms. Addition of peptidoglycan to the culture medium did not change the growth characteristics of the test cultures; however, an increase in the antagonism and hydrophobicity of Bifidobacterium sp. and Enterococcus sp. was observed, while the effect on enterobacteria was predominantly indifferent or inhibitory. The effect did not depend much on the source of peptidoglycan and was equally manifested on both indigenous and probiotic strains. The observed new property of peptidoglycan indicates its participation in the formation and functioning of microbiota. The obtained data on the regulation of the properties of microorganisms provide new possibilities for the correction and maintenance of host homeostasis through host-associated microbiota.
Topics: Antibiosis; Bacillus subtilis; Bacterial Proteins; Bifidobacterium; Candida; Cell Wall; Enterobacter; Enterococcus faecalis; Escherichia coli; Female; Humans; Lacticaseibacillus casei; Microbiological Techniques; Peptidoglycan; Staphylococcus aureus
PubMed: 34855091
DOI: 10.1007/s10517-021-05356-4 -
Trends in Microbiology Aug 2017Bacterial cell shape is a genetically encoded and inherited feature that is optimized for efficient growth, survival, and propagation of bacteria. In addition, bacterial... (Review)
Review
Bacterial cell shape is a genetically encoded and inherited feature that is optimized for efficient growth, survival, and propagation of bacteria. In addition, bacterial cell morphology is adaptable to changes in environmental conditions. Work in recent years has demonstrated that individual features of cell shape, such as length or curvature, arise through the spatial regulation of cell wall synthesis by cytoskeletal proteins. However, the mechanisms by which these different morphogenetic factors are coordinated and how they may be globally regulated in response to cell cycle and environmental cues are only beginning to emerge. Here, we have summarized recent advances that have been made to understand morphology in the dimorphic Gram-negative bacterium Caulobacter crescentus.
Topics: Bacterial Proteins; Caulobacter crescentus; Cell Cycle; Cell Division; Cell Wall; Cytoskeletal Proteins; Cytoskeleton; Microbial Viability; Peptidoglycan; Stress, Physiological
PubMed: 28359631
DOI: 10.1016/j.tim.2017.03.006 -
MBio Aug 2022Bacteria in general serve two main tasks: cell growth and division. Both processes include peptidoglycan extension to allow cell expansion and to form the poles of the...
Bacteria in general serve two main tasks: cell growth and division. Both processes include peptidoglycan extension to allow cell expansion and to form the poles of the daughter cells, respectively. The cyanobacterium forms filaments of communicated cells in which the outer membrane and the peptidoglycan sacculus, which is engrossed in the intercellular regions between contiguous cells, are continuous along the filament. During the growth of , peptidoglycan incorporation was weak at the cell periphery. During cell division, midcell peptidoglycan incorporation matched the localization of the divisome, and incorporation persisted in the intercellular septa, even after the division was completed. MreB, MreC, and MreD were located throughout the cell periphery and, in contrast to other bacteria, also to the divisome all along midcell peptidoglycan growth. In mutants bearing inactivated , or genes, which showed conspicuous alterations in the filament morphology, consecutive septal bands of peptidoglycan growth were frequently not parallel to each other and were irregularly spaced along the filament, reproducing the disposition of the Z-ring. Both lateral and septal growth was impaired in strains down-expressing Z-ring components, and MreB and MreD appeared to directly interact with some divisome components. We propose that, in , association with the divisome is a way for localization of MreB, MreC, and MreD at the cell poles, where they regulate lateral, midcell, and septal peptidoglycan growth with the latter being involved in localization and maintenance of the intercellular septal-junction protein structures that mediate cell-cell communication along the filament. Peptidoglycan surrounds the bacterial cell, being essential for the determination of the bacterium-specific morphology and survival. Peptidoglycan growth has been thoroughly investigated in some model rod-shaped bacteria, and more recently some representatives with disparate morphologies became into focus, revealing that patterns of peptidoglycan growth are much more diverse than previously anticipated. forms filaments of communicated cells exhibiting features of multicellular organisms, such as the production of morphogens and coupled circadian oscillations. Here, we showed that presented a distinct pattern of peptidoglycan growth characterized by continuous incorporation of material at the polar intercellular regions, contributing to assembling and maintaining the protein complexes that expand the septal peptidoglycan mediating intercellular molecular exchange in the filament.
Topics: Anabaena; Bacterial Proteins; Cell Division; Cell Wall; Peptidoglycan
PubMed: 35876506
DOI: 10.1128/mbio.01165-22 -
MBio Jul 2019species are obligate intracellular bacteria lacking a classical peptidoglycan sacculus but relying on peptidoglycan synthesis for cytokinesis. While septal...
species are obligate intracellular bacteria lacking a classical peptidoglycan sacculus but relying on peptidoglycan synthesis for cytokinesis. While septal peptidoglycan biosynthesis seems to be regulated by MreB actin and its membrane anchor RodZ rather than FtsZ tubulin in , the mechanism of peptidoglycan remodeling is poorly understood. An amidase conserved in is able to cleave peptide stems in peptidoglycan, but it is not clear how peptidoglycan glycan strands are cleaved since no classical lytic transglycosylase is encoded in chlamydial genomes. However, a protein containing a SpoIID domain, known to possess transglycosylase activity in , is conserved in We show here that the SpoIID homologue of the -related pathogen is a septal peptidoglycan-binding protein. Moreover, we demonstrate that SpoIID acts as a lytic transglycosylase on peptidoglycan and as a muramidase on denuded glycan strands As SpoIID-like proteins are widespread in nonsporulating bacteria, SpoIID might commonly be a septal peptidoglycan remodeling protein in bacteria, including obligate intracellular pathogens, and thus might represent a promising drug target. species are obligate intracellular bacteria and important human pathogens that have a minimal division machinery lacking the proteins that are essential for bacterial division in other species, such as FtsZ. Chlamydial division requires synthesis of peptidoglycan, which forms a ring at the division septum and is rapidly turned over. However, little is known of peptidoglycan degradation, because many peptidoglycan-degrading enzymes are not encoded by chlamydial genomes. Here we show that an homologue of SpoIID, a peptidoglycan-degrading enzyme involved in sporulation of bacteria such as , is expressed in , localizes at the division septum, and degrades peptidoglycan , indicating that SpoIID is not only involved in sporulation but also likely implicated in division of some bacteria.
Topics: Amino Acid Sequence; Bacterial Proteins; Cell Division; Chlamydia; Chlamydia Infections; Chromatography, High Pressure Liquid; Gene Expression; Humans; Peptidoglycan; Protein Binding; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Spores, Bacterial
PubMed: 31311880
DOI: 10.1128/mBio.01128-19 -
Biochemistry Jul 2018Gram-positive bacteria surround themselves with a multilayered macromolecular cell wall that is essential to cell survival and serves as a major target for antibiotics....
Gram-positive bacteria surround themselves with a multilayered macromolecular cell wall that is essential to cell survival and serves as a major target for antibiotics. The cell wall of Staphylococcus aureus is composed of two major structural components, peptidoglycan (PG) and wall teichoic acid (WTA), together creating a heterogeneous and insoluble matrix that poses a challenge to quantitative compositional analysis. Here, we present C cross polarization magic angle spinning solid-state nuclear magnetic resonance (NMR) spectra of intact cell walls, purified PG, and purified WTA. The spectra reveal the clear molecular differences in the two polymers and enable quantification of PG and WTA in isolated cell walls, an attractive alternative to estimating teichoic acid content from a phosphate analysis of completely pyrolyzed cell walls. Furthermore, we discovered that unique PG and WTA spectral signatures could be identified in whole-cell NMR spectra and used to compare PG and WTA levels among intact bacterial cell samples. The distinguishing whole-cell C NMR contributions associated with PG include the GlcNAc-MurNAc sugar carbons and glycyl α-carbons. WTA contributes carbons from the phosphoribitol backbone. Distinguishing N spectral signatures include glycyl amide nitrogens in PG and the esterified d-alanyl amine nitrogens in WTA. C NMR analysis was performed with samples at natural abundance and included 10 whole-cell sample comparisons. Changes consistent with altered PG and WTA content were detected in whole-cell spectra of bacteria harvested at different growth times and in cells treated with tunicamycin. This use of whole-cell NMR provides quantitative parameters of composition in the context of whole-cell activity.
Topics: Cell Wall; Nuclear Magnetic Resonance, Biomolecular; Peptidoglycan; Staphylococcus aureus; Teichoic Acids
PubMed: 29806458
DOI: 10.1021/acs.biochem.8b00495