scholarly journals Structural basis of peptidoglycan endopeptidase regulation

2020 ◽  
Vol 117 (21) ◽  
pp. 11692-11702 ◽  
Author(s):  
Jung-Ho Shin ◽  
Alan G. Sulpizio ◽  
Aaron Kelley ◽  
Laura Alvarez ◽  
Shannon G. Murphy ◽  
...  
Keyword(s):  
Cell Wall ◽  
Structural Basis ◽  
Bacterial Cells ◽  
Cell Wall Degradation ◽  
Open Conformation ◽  
Poor Understanding ◽  
A Cell ◽  
Inhibitory Domain

Most bacteria surround themselves with a cell wall, a strong meshwork consisting primarily of the polymerized aminosugar peptidoglycan (PG). PG is essential for structural maintenance of bacterial cells, and thus for viability. PG is also constantly synthesized and turned over; the latter process is mediated by PG cleavage enzymes, for example, the endopeptidases (EPs). EPs themselves are essential for growth but also promote lethal cell wall degradation after exposure to antibiotics that inhibit PG synthases (e.g., β-lactams). Thus, EPs are attractive targets for novel antibiotics and their adjuvants. However, we have a poor understanding of how these enzymes are regulated in vivo, depriving us of novel pathways for the development of such antibiotics. Here, we have solved crystal structures of the LysM/M23 family peptidase ShyA, the primary EP of the cholera pathogenVibrio cholerae. Our data suggest that ShyA assumes two drastically different conformations: a more open form that allows for substrate binding and a closed form, which we predicted to be catalytically inactive. Mutations expected to promote the open conformation caused enhanced activity in vitro and in vivo, and these results were recapitulated in EPs from the divergent pathogensNeisseria gonorrheaeandEscherichia coli. Our results suggest that LysM/M23 EPs are regulated via release of the inhibitory Domain 1 from the M23 active site, likely through conformational rearrangement in vivo.

scholarly journals Structural basis of peptidoglycan endopeptidase regulation

2019 ◽  
Author(s):  
Jung-Ho Shin ◽  
Alan G. Sulpizio ◽  
Aaron Kelley ◽  
Laura Alvarez ◽  
Shannon G. Murphy ◽  
...  
Keyword(s):  
Cell Wall ◽  
Vibrio Cholerae ◽  
Active Site ◽  
Normal Growth ◽  
Structural Basis ◽  
Bacterial Cells ◽  
Cell Wall Digestion ◽  
Novel Antibiotics

AbstractMost bacteria surround themselves with a cell wall, a strong meshwork consisting primarily of the polymerized aminosugar peptidoglycan (PG). PG is essential for structural maintenance of bacterial cells, and thus for viability. PG is also constantly synthesized and turned over, the latter process is mediated by PG cleavage enzymes, for example the endopeptidases (EPs). EPs themselves are essential for growth, but also promote lethal cell wall degradation after exposure to antibiotics that inhibit PG synthases (e.g., β-lactams). Thus, EPs are attractive targets for novel antibiotics and their adjuvants. However, we have a poor understanding of how these enzymes are regulated in vivo, depriving us of novel pathways for the development of such antibiotics. Here, we have solved crystal structures of the LysM/M23 family peptidase ShyA, the primary EP of the cholera pathogen Vibrio cholerae. Our data suggest that ShyA assumes two drastically different conformations; a more open form that allows for substrate binding, and a closed form, which we predicted to be catalytically inactive. Mutations expected to promote the open conformation caused enhanced activity in vitro and in vivo, and these results were recapitulated in EPs from the divergent pathogens Neisseria gonorrheae and Escherichia coli. Our results suggest that LysM/M23 EPs are regulated via release of the inhibitory Domain1 from the M23 active site, likely through conformational re-arrangement in vivo.SignificanceBacteria digest their cell wall following exposure to antibiotics like penicillin. The endopeptidases (EPs) are among the proteins that catalyze cell wall digestion processes after antibiotic exposure, but we do not understand how these enzymes are regulated during normal growth. Herein, we present the structure of the major EP from the diarrheal pathogen Vibrio cholerae. Surprisingly, we find that EPs from this and other pathogens appear to be produced as a largely inactive precursor that undergoes a conformational shift exposing the active site to engage in cell wall digestion. These results enhance our understanding of how EPs are regulated and could open the door for the development of novel antibiotics that overactivate cell wall digestion processes.

scholarly journals L-form bacteria, cell walls and the origins of life

Open Biology ◽  
2013 ◽  
Vol 3 (1) ◽  
pp. 120143 ◽  
Author(s):  
Jeff Errington
Keyword(s):  
Cell Wall ◽  
Cell Envelope ◽  
Evolutionary Development ◽  
Last Common Ancestor ◽  
Bacterial Cells ◽  
A Cell ◽  
Evolutionary Radiations ◽  
Key Steps ◽  
Bacterial Domain

The peptidoglycan wall is a defining feature of bacterial cells and was probably already present in their last common ancestor. L-forms are bacterial variants that lack a cell wall and divide by a variety of processes involving membrane blebbing, tubulation, vesiculation and fission. Their unusual mode of proliferation provides a model for primitive cells and is reminiscent of recently developed in vitro vesicle reproduction processes. Invention of the cell wall may have underpinned the explosion of bacterial life on the Earth. Later innovations in cell envelope structure, particularly the emergence of the outer membrane of Gram-negative bacteria, possibly in an early endospore former, seem to have spurned further major evolutionary radiations. Comparative studies of bacterial cell envelope structure may help to resolve the early key steps in evolutionary development of the bacterial domain of life.

scholarly journals Non-Lytic Antibacterial Peptides That Translocate Through Bacterial Membranes to Act on Intracellular Targets

2019 ◽  
Vol 20 (19) ◽  
pp. 4877 ◽  
Author(s):  
Marlon H. Cardoso ◽  
Beatriz T. Meneguetti ◽  
Bruna O. Costa ◽  
Danieli F. Buccini ◽  
Karen G. N. Oshiro ◽  
...  
Keyword(s):  
Cell Wall ◽  
Protein Synthesis ◽  
Pathogenic Bacteria ◽  
Biological Properties ◽  
Antibacterial Peptides ◽  
Bacterial Cells ◽  
Bacterial Membranes ◽  
Intracellular Targets

The advent of multidrug resistance among pathogenic bacteria has attracted great attention worldwide. As a response to this growing challenge, diverse studies have focused on the development of novel anti-infective therapies, including antimicrobial peptides (AMPs). The biological properties of this class of antimicrobials have been thoroughly investigated, and membranolytic activities are the most reported mechanisms by which AMPs kill bacteria. Nevertheless, an increasing number of works have pointed to a different direction, in which AMPs are seen to be capable of displaying non-lytic modes of action by internalizing bacterial cells. In this context, this review focused on the description of the in vitro and in vivo antibacterial and antibiofilm activities of non-lytic AMPs, including indolicidin, buforin II PR-39, bactenecins, apidaecin, and drosocin, also shedding light on how AMPs interact with and further translocate through bacterial membranes to act on intracellular targets, including DNA, RNA, cell wall and protein synthesis.

scholarly journals Different Cell Wall-Degradation Ability Leads to Tissue-Specificity between Xanthomonas oryzae pv. oryzae and Xanthomonas oryzae pv. oryzicola

Pathogens ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 187
Author(s):  
Jianbo Cao ◽  
Chuanliang Chu ◽  
Meng Zhang ◽  
Limin He ◽  
Lihong Qin ◽  
...  
Keyword(s):  
Cell Wall ◽  
Tissue Specificity ◽  
Mesophyll Cell ◽  
Xanthomonas Oryzae ◽  
Cell Wall Degradation ◽  
Intercellular Spaces ◽  
Mesophyll Cells ◽  
Degradation Ability

Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xoc) lead to the devastating rice bacterial diseases and have a very close genetic relationship. There are tissue-specificity differences between Xoo and Xoc, i.e., Xoo only proliferating in xylem vessels and Xoc spreading in intercellular space of mesophyll cell. But there is little known about the determinants of tissue-specificity between Xoo and Xoc. Here we show that Xoc can spread in the intercellular spaces of mesophyll cells to form streak lesions. But Xoo is restricted to growth in the intercellular spaces of mesophyll cells on the inoculation sites. In vivo, Xoc largely breaks the surface and inner structures of cell wall in mesophyll cells in comparison with Xoo. In vitro, Xoc strongly damages the cellulose filter paper in comparison with Xoo. These results suggest that the stronger cell wall-degradation ability of Xoc than that of Xoo may be directly determining the tissue-specificity.

scholarly journals Phosphorylation-dependent activation of the cell wall synthase PBP2a in Streptococcus pneumoniae by MacP

2018 ◽  
Vol 115 (11) ◽  
pp. 2812-2817 ◽  
Author(s):  
Andrew K. Fenton ◽  
Sylvie Manuse ◽  
Josué Flores-Kim ◽  
Pierre Simon Garcia ◽  
Chryslène Mercy ◽  
...  
Keyword(s):  
Cell Wall ◽  
Streptococcus Pneumoniae ◽  
Drug Targets ◽  
Synthetic Activity ◽  
Bacterial Cells ◽  
Cell Wall Assembly ◽  
Division Site ◽  
A Cell ◽  
Wall Assembly

Most bacterial cells are surrounded by an essential cell wall composed of the net-like heteropolymer peptidoglycan (PG). Growth and division of bacteria are intimately linked to the expansion of the PG meshwork and the construction of a cell wall septum that separates the nascent daughter cells. Class A penicillin-binding proteins (aPBPs) are a major family of PG synthases that build the wall matrix. Given their central role in cell wall assembly and importance as drug targets, surprisingly little is known about how the activity of aPBPs is controlled to properly coordinate cell growth and division. Here, we report the identification of MacP (SPD_0876) as a membrane-anchored cofactor of PBP2a, an aPBP synthase of the Gram-positive pathogen Streptococcus pneumoniae. We show that MacP localizes to the division site of S. pneumoniae, forms a complex with PBP2a, and is required for the in vivo activity of the synthase. Importantly, MacP was also found to be a substrate for the kinase StkP, a global cell cycle regulator. Although StkP has been implicated in controlling the balance between the elongation and septation modes of cell wall synthesis, none of its substrates are known to modulate PG synthetic activity. Here we show that a phosphoablative substitution in MacP that blocks StkP-mediated phosphorylation prevents PBP2a activity without affecting the MacP–PBP2a interaction. Our results thus reveal a direct connection between PG synthase function and the control of cell morphogenesis by the StkP regulatory network.

scholarly journals Conserved mechanism of cell-wall synthase regulation revealed by the identification of a new PBP activator inPseudomonas aeruginosa

2018 ◽  
Vol 115 (12) ◽  
pp. 3150-3155 ◽  
Author(s):  
Neil G. Greene ◽  
Coralie Fumeaux ◽  
Thomas G. Bernhardt
Keyword(s):  
Cell Wall ◽  
Drug Targets ◽  
Bacterial Cells ◽  
Acinetobacter Baylyi ◽  
Gram Negative ◽  
E Coli ◽  
Outer Membrane Lipoprotein ◽  
Synthase Regulation

Penicillin-binding proteins (PBPs) are synthases required to build the essential peptidoglycan (PG) cell wall surrounding most bacterial cells. The mechanisms regulating the activity of these enzymes to control PG synthesis remain surprisingly poorly defined given their status as key antibiotic targets. Several years ago, the outer-membrane lipoproteinEcLpoB was identified as a critical activator ofEscherichia coliPBP1b (EcPBP1b), one of the major PG synthases of this organism. Activation ofEcPBP1b is mediated through the association ofEcLpoB with a regulatory domain onEcPBP1b called UB2H. Notably,Pseudomonas aeruginosaalso encodes PBP1b (PaPBP1b), which possesses a UB2H domain, but this bacterium lacks an identifiable LpoB homolog. We therefore searched for potentialPaPBP1b activators and identified a lipoprotein unrelated to LpoB that is required for the in vivo activity ofPaPBP1b. We named this protein LpoP and found that it interacts directly withPaPBP1b in vitro and is conserved in many Gram-negative species. Importantly, we also demonstrated thatPaLpoP-PaPBP1b as well as an equivalent protein pair fromAcinetobacter baylyican fully substitute forEcLpoB-EcPBP1b inE. colifor PG synthesis. Furthermore, we show that amino acid changes inPaPBP1b that bypass thePaLpoP requirement map to similar locations in the protein as changes promotingEcLpoB bypass inEcPBP1b. Overall, our results indicate that, although different Gram-negative bacteria activate their PBP1b synthases with distinct lipoproteins, they stimulate the activity of these important drug targets using a conserved mechanism.

scholarly journals Antibacterial efficacy of Jackfruit rag extract against clinically important pathogens and validation of its antimicrobial activity in Shigella dysenteriae infected Drosophila melanogaster infection model

2020 ◽  
Author(s):  
NV Dhwani ◽  
Gayathri Raju ◽  
Sumi E Mathew ◽  
Gaurav Baranwal ◽  
Shivakumar B Shivaram ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacterial Cell ◽  
Antibacterial Property ◽  
Mouse Fibroblast ◽  
Bacterial Cell Wall ◽  
Shigella Dysenteriae ◽  
Infection Model ◽  
Bacterial Cells

AbstractThe aim of this study was to determine the antibacterial property of extract derived from a part of the Jackfruit called ‘rag’, that is generally considered as fruit waste. Morpho-physical characterization of the Jackfruit rag extract (JFRE) was performed using gas-chromatography, where peaks indicative of furfural; pentanoic acid; and hexadecanoic acid were observed. In vitro biocompatibility of JFRE was performed using the MTT assay, which showed comparable cellular viability between extract-treated and untreated mouse fibroblast cells. Agar well disc diffusion assay exhibited JFRE induced zones of inhibition for a wide variety of laboratory and clinical strains of gram-positive and gram-negative bacteria. Analysis of electron microscope images of bacterial cells suggests that JFRE induces cell death by disintegration of the bacterial cell wall and precipitating intracytoplasmic clumping. The antibacterial activity of the JFREs was further validated in vivo using Shigella dysenteriae infected fly model, where JFRE pre-fed flies infected with S. dysenteriae had significantly reduced mortality compared to controls. JFRE demonstrates broad antibacterial property, both in vitro and in vivo, possibly by its activity on bacterial cell wall. This study highlights the importance of exploring alternative sources of antibacterial compounds, especially from plant-derived waste, that could provide economical and effective solutions to current challenges in antimicrobial therapy.

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