Karl Ocius

World J Microbiol Biotechnol. 2023 Aug 12;39(10):277. doi: 10.1007/s11274-023-03723-z.

ABSTRACT

Vibrio natriegens is a fast-growing, non-pathogenic marine bacterium with promising features for biotechnological applications such as high-level recombinant protein production or fast DNA propagation. A remarkable short generation time (< 10 min), robust proteosynthetic activity and versatile metabolism with abilities to utilise wide range of substrates contribute to its establishment as a future industrial platform for fermentation processes operating with high productivity.D,D-carboxypeptidases are membrane-associated enzymes involved in peptidoglycan biosynthesis and cell wall formation. This study investigates the impact of overexpressed D,D-carboxypeptidases on membrane integrity and the increased leakage of intracellular proteins into the growth medium in V. natriegens. Our findings confirm that co-expression of these enzymes can enhance membrane permeability, thereby facilitating the transport of target proteins into the extracellular environment, without the need for secretion signals, tags, or additional permeabilization methods. Using only a single step IMAC chromatography, we were able to purify AfKatG, MDBP or Taq polymerase in total yields of 117.9 ± 56.0 mg/L, 36.5 ± 12.9 mg/L and 26.5 ± 6.0 mg/L directly from growth medium, respectively. These results demonstrate the feasibility of our V. natriegens based system as a broadly applicable extracellular tag-less recombinant protein producer.

PMID:37568013 | PMC:PMC10421817 | DOI:10.1007/s11274-023-03723-z

Bioorg Med Chem Lett. 2023 Sep 1;93:129428. doi: 10.1016/j.bmcl.2023.129428. Epub 2023 Aug 2.

ABSTRACT

Imaging or killing of a specific pathogen is of significance for precise therapy. Staphylococcus aureus (S. aureus) is an infectious gram-positive bacteria relying on Sortase A (SrtA) to anchor cell surface protein on peptidoglycan. We herein report signal-on labeling of S. aureus with self-quenched optical probes featuring vancomycin-conjugated SrtA substrate that is flanked by a dabcyl moiety paired with either fluorescein or eosine photosensizer (PS). SrtA-mediated cleavage of the substrate motif releases the dabcyl quencher, leading to covalent labeling of peptidoglycan with fluorescein or PS of restored photophysical property. The dual biomarked-enabled peptidoglycan labeling enables signal-on imaging and effective photodynamic destruction of S. aureus, suggesting a protheranostic approch activatable to SrtA-positive bacteria engaged in myriad diseases.

PMID:37541632 | DOI:10.1016/j.bmcl.2023.129428

Chem Sci. 2023 May 30;14(26):7262-7278. doi: 10.1039/d2sc06858c. eCollection 2023 Jul 5.

ABSTRACT

Disruption of bacterial cell wall biosynthesis in Mycobacterium tuberculosis is a promising target for treating tuberculosis. The l,d-transpeptidase Ldt_Mt2, which is responsible for the formation of 3 → 3 cross-links in the cell wall peptidoglycan, has been identified as essential for M. tuberculosis virulence. We optimised a high-throughput assay for Ldt_Mt2, and screened a targeted library of ∼10 000 electrophilic compounds. Potent inhibitor classes were identified, including established (e.g., β-lactams) and unexplored covalently reacting electrophilic groups (e.g., cyanamides). Protein-observed mass spectrometric studies reveal most classes to react covalently and irreversibly with the Ldt_Mt2 catalytic cysteine (Cys354). Crystallographic analyses of seven representative inhibitors reveal induced fit involving a loop enclosing the Ldt_Mt2 active site. Several of the identified compounds have a bactericidal effect on M. tuberculosis within macrophages, one with an MIC₅₀ value of ∼1 μM. The results provide leads for the development of new covalently reaction inhibitors of Ldt_Mt2 and other nucleophilic cysteine enzymes.

PMID:37416715 | PMC:PMC10321483 | DOI:10.1039/d2sc06858c

Zhonghua Jie He He Hu Xi Za Zhi. 2023 Aug 12;46(8):797-805. doi: 10.3760/cma.j.cn112147-20230111-00017.

ABSTRACT

Objective: To evaluate the activity of six β-lactams in combination with three β-lactamase inhibitors against mycobacterium tuberculosis(MTB) in vitro. Methods: A total of 105 multidrug-resistant tuberculosis (MDR-TB) strains from different regions of Henan province from January to September 2020 were included in this study. Drug activity of six β-lactams (biapenem, meropenem, imipenem, doripenem, ertapenem and tebipenem) alone or in combination with β-lactamase inhibitors (clavulanic acid, avibactam and relebactam) was examined by minimum inhibitory concentration method (MICs) against 105 clinical isolates. Mutations of blaC, ldt_mt1 and ldt_mt2 were analyzed by PCR and DNA sequencing. Chi-square test was used to compare the antimicrobial activities of different β-lactam drugs. Results: Out of the β-lactams used herein, tebipenem was the most effective against MDR-TB and had an MIC₅₀ value of 8 mg/L(χ²=123.70,P=0.001). Besides, after the addition of β-lactamase inhibitors, the MICs of most β-lactam drugs were reduced more evidently in the presence of avibactam and relebactam compared to clavulanic acid.Especially, relebactam decreased both the MIC50 and MIC90 of telbipenem by 16-fold, and diluted the MIC of 23 (21.90%) and 41 (39.04%) isolatesby 32-fold and 16-fold.In addition, a total of 13.33% (14/105) of isolates harbored mutations in the blaC gene, with three different nucleotide substitutions: AGT333AGG, AAC638ACC and ATC786ATT. For the strains with Ser111Arg and Asn213Thr substitution in BlaC, the MIC values of the meropenem-clavulanate combination were reduced compared with a synonymous single nucleotide polymorphism (SNP) group. Conclusions: Both avibactam and relebactam had better synergistic effects on β-lactams than clavulanic acid. The combination of tebipenem and relebactam showed the most potent activity against MDR-TB isolates. In addition, the Ser111Arg and Asn213Thr substitution of BlaC may be associated with an increased susceptibility of MDR-TB isolates to meropenem in the presence of clavulanate.

PMID:37536990 | DOI:10.3760/cma.j.cn112147-20230111-00017

World J Microbiol Biotechnol. 2023 Aug 12;39(10):277. doi: 10.1007/s11274-023-03723-z.

ABSTRACT

Vibrio natriegens is a fast-growing, non-pathogenic marine bacterium with promising features for biotechnological applications such as high-level recombinant protein production or fast DNA propagation. A remarkable short generation time (< 10 min), robust proteosynthetic activity and versatile metabolism with abilities to utilise wide range of substrates contribute to its establishment as a future industrial platform for fermentation processes operating with high productivity.D,D-carboxypeptidases are membrane-associated enzymes involved in peptidoglycan biosynthesis and cell wall formation. This study investigates the impact of overexpressed D,D-carboxypeptidases on membrane integrity and the increased leakage of intracellular proteins into the growth medium in V. natriegens. Our findings confirm that co-expression of these enzymes can enhance membrane permeability, thereby facilitating the transport of target proteins into the extracellular environment, without the need for secretion signals, tags, or additional permeabilization methods. Using only a single step IMAC chromatography, we were able to purify AfKatG, MDBP or Taq polymerase in total yields of 117.9 ± 56.0 mg/L, 36.5 ± 12.9 mg/L and 26.5 ± 6.0 mg/L directly from growth medium, respectively. These results demonstrate the feasibility of our V. natriegens based system as a broadly applicable extracellular tag-less recombinant protein producer.

PMID:37568013 | PMC:PMC10421817 | DOI:10.1007/s11274-023-03723-z

Innate Immun. 2023 Aug 7:17534259231193926. doi: 10.1177/17534259231193926. Online ahead of print.

ABSTRACT

Consumption of diets high in fat has been linked to the development of obesity and related metabolic complications. Such associations originate from the enhanced, chronic, low-grade inflammation mediated by macrophages in response to translocated bacteria, bacterial products, or dietary constituents such as fatty acids (FAs). Nucleotide-binding Oligomerization Domain 2 (NOD2) senses muramyl dipeptide (MDP), a component of bacterial peptidoglycan. The inability to sense peptidoglycan through NOD2 has been demonstrated to lead to dysbiosis, increased bacterial translocation, inflammation and metabolic dysfunction. Currently, it is unknown how consumption of HFDs with different FA compositions might influence NOD2-dependent responses. In this study, we subjected WT mice to a control diet or to HFDs comprised of various ratios of unsaturated to saturated fats and determined the macrophage response to TLR4 and NOD2 agonists. A HFD with equal ratios of saturated and unsaturated fats enhanced subsequent responsiveness of macrophages to LPS but not to MDP. However, a high-unsaturated fat diet (HUFD) or a high-saturated fat diet (HSFD) both decreased the responsiveness to NOD2 agonists compared to that observed in control diet (CD) fed mice. These data suggest that dietary fatty acid composition can influence the subsequent macrophage responsiveness to bacterial products.

PMID:37545346 | DOI:10.1177/17534259231193926

Nat Commun. 2023 Aug 9;14(1):4815. doi: 10.1038/s41467-023-40494-5.

ABSTRACT

The cell envelope of Gram-negative bacteria belonging to the Burkholderia cepacia complex (Bcc) presents unique restrictions to antibiotic penetration. As a consequence, Bcc species are notorious for causing recalcitrant multidrug-resistant infections in immunocompromised individuals. Here, we present the results of a genome-wide screen for cell envelope-associated resistance and susceptibility determinants in a Burkholderia cenocepacia clinical isolate. For this purpose, we construct a high-density, randomly-barcoded transposon mutant library and expose it to 19 cell envelope-targeting antibiotics. By quantifying relative mutant fitness with BarSeq, followed by validation with CRISPR-interference, we profile over a hundred functional associations and identify mediators of antibiotic susceptibility in the Bcc cell envelope. We reveal connections between β-lactam susceptibility, peptidoglycan synthesis, and blockages in undecaprenyl phosphate metabolism. The synergy of the β-lactam/β-lactamase inhibitor combination ceftazidime/avibactam is primarily mediated by inhibition of the PenB carbapenemase. In comparison with ceftazidime, avibactam more strongly potentiates the activity of aztreonam and meropenem in a panel of Bcc clinical isolates. Finally, we characterize in Bcc the iron and receptor-dependent activity of the siderophore-cephalosporin antibiotic, cefiderocol. Our work has implications for antibiotic target prioritization, and for using additional combinations of β-lactam/β-lactamase inhibitors that can extend the utility of current antibacterial therapies.

PMID:37558695 | PMC:PMC10412643 | DOI:10.1038/s41467-023-40494-5

Microbiol Spectr. 2023 Aug 10:e0190623. doi: 10.1128/spectrum.01906-23. Online ahead of print.

ABSTRACT

Lysins (peptidoglycan hydrolases) are promising new protein-based antimicrobial candidates under development to address rising antibiotic resistance encountered among pathogenic bacteria. Exebacase is an antistaphylococcal lysin and the first member of the lysin class to have entered clinical trials in the United States. In this study, the bacteriolytic activity of exebacase was characterized with time-kill assays, turbidity reduction assays, and microscopy. Three methicillin-susceptible Staphylococcus aureus and three methicillin-resistant S. aureus isolates were tested in time-kill assays over a range of concentrations from 0.25 to 8 × MIC. Exebacase demonstrated a concentration-dependent killing and showed bactericidal activity (≥3 log₁₀ kill achieved relative to the starting inoculum) within 3 h at 1 × MIC against all strains tested. Dose-dependent lysis by exebacase was, furthermore, observed in the turbidity reduction assay, wherein decreases in initial OD₆₀₀ of 50% were observed within ~15 min at concentrations as low as 4 µg/mL. Membrane dissolution, loss of cytoplasmic material, and lysis were confirmed by video and electron microscopy. The demonstrated rapid bacteriolytic effect of exebacase is an important distinguishing feature of this novel modality. IMPORTANCE To guide the development of an investigational new antibacterial entity, microbiological data are required to evaluate the killing kinetics against target organism(s). Exebacase is a lysin (peptidoglycan hydrolase) that represents a novel antimicrobial modality based on degradation of the cell wall of Staphylococcus aureus. Killing by exebacase was determined in multiple assay formats including time-kill assays, wherein reductions of viability of ≥3 log₁₀ colony-forming units/mL were observed within 3 h for multiple different isolates tested, consistent with very rapid bactericidal activity. Rapid reductions in optical density were likewise observed in exebacase-treated cultures, which were visually consistent with microscopic observations of rapid lysis. Overall, exebacase provides a novel antimicrobial modality against S. aureus, characterized by a rapid cidal and lytic activity.

PMID:37561151 | DOI:10.1128/spectrum.01906-23

bioRxiv. 2023 Jul 12:2023.07.12.548665. doi: 10.1101/2023.07.12.548665. Preprint.

ABSTRACT

Peptidoglycan (PG) is the main component of the bacterial cell wall; it maintains cell shape while protecting the cell from internal osmotic pressure and external environmental challenges. PG synthesis is essential for bacterial growth and survival, and a series of PG modifications are required to allow expansion of the sacculus. Endopeptidases (EPs), for example, cleave the crosslinks between adjacent PG strands to allow the incorporation of newly synthesized PG. EPs are collectively essential for bacterial growth and must likely be carefully regulated to prevent sacculus degradation and cell death. However, EP regulation mechanisms are poorly understood. Here, we used TnSeq to uncover novel EP regulation factors in Vibrio cholerae . This screen revealed that the carboxypeptidase DacA1 (PBP5) alleviates EP toxicity. dacA1 is essential for viability on LB medium, and this essentiality was suppressed by EP overexpression, revealing that EP toxicity both mitigates, and is mitigated by, a defect in dacA1 . A subsequent suppressor screen to restore viability of ΔdacA1 in LB medium was answered by hypomorphic mutants in the PG synthesis pathway, as well as mutations that promote PG degradation. Our data thus reveal a key role of DacA1 in maintaining the balance between PG synthesis and degradation.

PMID:37503280 | PMC:PMC10369974 | DOI:10.1101/2023.07.12.548665

Chem Sci. 2023 May 30;14(26):7262-7278. doi: 10.1039/d2sc06858c. eCollection 2023 Jul 5.

ABSTRACT

Disruption of bacterial cell wall biosynthesis in Mycobacterium tuberculosis is a promising target for treating tuberculosis. The l,d-transpeptidase Ldt_Mt2, which is responsible for the formation of 3 → 3 cross-links in the cell wall peptidoglycan, has been identified as essential for M. tuberculosis virulence. We optimised a high-throughput assay for Ldt_Mt2, and screened a targeted library of ∼10 000 electrophilic compounds. Potent inhibitor classes were identified, including established (e.g., β-lactams) and unexplored covalently reacting electrophilic groups (e.g., cyanamides). Protein-observed mass spectrometric studies reveal most classes to react covalently and irreversibly with the Ldt_Mt2 catalytic cysteine (Cys354). Crystallographic analyses of seven representative inhibitors reveal induced fit involving a loop enclosing the Ldt_Mt2 active site. Several of the identified compounds have a bactericidal effect on M. tuberculosis within macrophages, one with an MIC₅₀ value of ∼1 μM. The results provide leads for the development of new covalently reaction inhibitors of Ldt_Mt2 and other nucleophilic cysteine enzymes.

PMID:37416715 | PMC:PMC10321483 | DOI:10.1039/d2sc06858c

Chem Sci. 2023 May 31;14(25):6975-6985. doi: 10.1039/d3sc01209c. eCollection 2023 Jun 28.

ABSTRACT

The bacterial transpeptidase Sortase A (SrtA) is a surface enzyme of Gram-positive pathogenic bacteria. It has been shown to be an essential virulence factor for the establishment of various bacterial infections, including septic arthritis. However, the development of potent Sortase A inhibitors remains an unmet challenge. Sortase A relies on a five amino acid sorting signal (LPXTG), by which it recognizes its natural target. We report the synthesis of a series of peptidomimetic inhibitors of Sortase A based on the sorting signal, supported by computational binding analysis. By employing a FRET-compatible substrate, our inhibitors were assayed in vitro. Among our panel, we identified several promising inhibitors with IC₅₀ values below 200 μM, with our strongest inhibitor - LPRDSar - having an IC₅₀ of 18.9 μM. Furthermore, it was discovered that three of our compounds show an effect on growth and biofilm inhibition of pathogenic Staphylococcus aureus, with the inclusion of a phenyl ring seemingly key to this effect. The most promising compound in our panel, BzLPRDSar, could inhibit biofilm formation at concentrations as low as 32 μg mL^-1, manifesting it as a potential future drug lead. This could lead to treatments for MRSA infections in clinics and diseases such as septic arthritis, which has been directly linked with SrtA.

PMID:37389257 | PMC:PMC10306101 | DOI:10.1039/d3sc01209c

Nan Fang Yi Ke Da Xue Xue Bao. 2023 Jun 20;43(6):1002-1009. doi: 10.12122/j.issn.1673-4254.2023.06.16.

ABSTRACT

OBJECTIVE: To explore the interaction between Tubulin beta 4B class IVb (TUBB4B) and Agtpbp1/cytosolic carboxypeptidase- like1 (CCP1) in mouse primary spermatocytes (GC-2 cells) and the role of TUBB4B in regulating the development of GC-2 cells.

METHODS: Lentiviral vectors were used to infect GC-2 cells to construct TUBB4B knockdown and negative control (NC-KD) cells. The stable cell lines with TUBB4B overexpression (Tubb4b-OE) and the negative control (NC-OE) cells were screened using purinomycin. RT-qPCR and Western blotting were used to verify successful cell modeling and explore the relationship between TUBB4B and CCP1 expressions in GC-2 cells. The effects of TUBB4B silencing and overexpression on the proliferation and cell cycle of GC-2 cells were evaluated using CCK8 assay and flow cytometry. The signaling pathway proteins showing significant changes in response to TUBB4B silencing or overexpression were identified using Western blotting and immunofluorescence assay and then labeled for verification at the cellular level.

RESULTS: Both TUBB4B silencing and overexpression in GC-2 cells caused consistent changes in the mRNA and protein expressions of CCP1 (P < 0.05). Similarly, TUBB4B expression also showed consistent changes at the mRNA and protein after CCP1 knockdown and restoration (P < 0.05). TUBB4B knockdown and overexpression had no significant effect on proliferation rate or cell cycle of GC-2 cells, but caused significant changes in the key proteins of the nuclear factor kappa-B (NF-κB) signaling pathway (p65 and p-p65) and the mitogen-activated protein kinase (MAPK) signaling pathway (ErK1/2 and p-Erk1/2) (P < 0.05); CCP1 knockdown induced significant changes in PolyE expression in GC-2 cells (P < 0.05).

CONCLUSIONS: TUBB4B and CCP1 interact via a mutual positive regulation mechanism in GC-2 cells. CCP-1 can deglutamize TUBB4B, and the latter is involved in the regulation of NF-κB and MAPK signaling pathways in primary spermatocytes.

PMID:37439173 | PMC:PMC10339298 | DOI:10.12122/j.issn.1673-4254.2023.06.16

bioRxiv. 2023 May 3:2023.05.03.539199. doi: 10.1101/2023.05.03.539199. Preprint.

ABSTRACT

Mechanisms by which Mycobacterium tuberculosis (Mtb) evades pathogen recognition receptor activation during infection may offer insights for the development of improved tuberculosis (TB) vaccines. Whilst Mtb elicits NOD-2 activation through host recognition of its peptidoglycan-derived muramyl dipeptide (MDP), it masks the endogenous NOD-1 ligand through amidation of glutamate at the second position in peptidoglycan sidechains. As the current BCG vaccine is derived from pathogenic mycobacteria, a similar situation prevails. To alleviate this masking ability and to potentially improve efficacy of the BCG vaccine, we used CRISPRi to inhibit expression of the essential enzyme pair, MurT-GatD, implicated in amidation of peptidoglycan sidechains. We demonstrate that depletion of these enzymes results in reduced growth, cell wall defects, increased susceptibility to antibiotics and altered spatial localization of new peptidoglycan. In cell culture experiments, training of monocytes with this recombinant BCG yielded improved control of Mtb growth. In the murine model of TB infection, we demonstrate that depletion of MurT-GatD in BCG, resulting in unmasking of the D-glutamate diaminopimelate (iE-DAP) NOD-1 ligand, yields superior prevention of TB disease compared to the standard BCG vaccine. This work demonstrates the feasibility of gene regulation platforms such as CRISPRi to alter antigen presentation in BCG in a bespoke manner that tunes immunity towards more effective protection against TB disease.

PMID:37205421 | PMC:PMC10187164 | DOI:10.1101/2023.05.03.539199

Microlife. 2022 Jun 30;3:uqac009. doi: 10.1093/femsml/uqac009. eCollection 2022.

ABSTRACT

Bacterial membrane vesicles (MVs) have been reported to kill other bacteria. In the case of Pseudomonas aeruginosa the bactericidal activity has been attributed to an unidentified 26 kDa peptidoglycan (PG) hydrolase that is associated with MVs and gives rise to a lytic band on zymograms using murein sacculi as substrate. In this study, we employed a proteomics approach to show that this PG hydrolase is the AmphD3 amidase. The analysis of an amphD3 mutant as well as of an AmphD3 overexpression derivative revealed that this enzyme is not required for the bactericidal activity of P. aeruginosa MVs but is involved in cell wall recycling and thus protects the cell against PG damage. Another 23 kDa PG hydrolase, which we observed on zymograms of SOS-induced MVs, was identified as the endolysin Lys, which triggers explosive cell lysis but is shown to be dispensable for MV-mediated killing. We conclude that the lytic activities observed on zymograms do not correlate with the bactericidal potential of MVs. We demonstrate that P. aeruginosa MVs are enriched for several autolysins, suggesting that the predatory activity of MVs depends on the combined action of different murein hydrolases.

PMID:37229443 | PMC:PMC10117874 | DOI:10.1093/femsml/uqac009

Anim Biotechnol. 2023 May 25:1-10. doi: 10.1080/10495398.2023.2214189. Online ahead of print.

ABSTRACT

Pathogen-associated molecular patterns (PAMPs) such as lipopolysaccharide (LPS), peptidoglycan (PGN), Polyinosinic-polycytidylic acid (poly I:C), and CpG Oligodeoxynucleotides (ODN) are recognized by Toll-like receptors (TLR). This study aimed to investigate the effect of diverse PAMPs on the transcription of TLR signaling pathway genes in goat blood. Whole blood was collected from 3 female BoerXSpanish goats and treated with the following PAMPs: 10 µg/ml LPS, PGN, CpG ODN (2216), CpG ODN (2006), and 12.5 µg/ml Poly I:C. Blood-treated PBS served as a control. The expression of 84 genes in the human TLR signaling pathway RT2 PCR Array (Qiagen) was evaluated using real-time PCR. Treatment with PBS affected the expression of 74 genes, Poly I:C affected the expression of 40 genes, t ODN 2006 affected the expression of 50 genes, ODN 2216 affected the expression of 52 genes, LPS affected the expression of 49 genes, while PGN affected the expression of 49 genes. Our results show that PAMPs modulated and increased the expression of genes in the TLR signaling pathway. These results highlight important insights into how the host responds to different pathogens and may help design adjuvants for therapeutics and vaccines that target different.

PMID:37226739 | DOI:10.1080/10495398.2023.2214189

Curr Oncol. 2023 May 4;30(5):4724-4735. doi: 10.3390/curroncol30050356.

ABSTRACT

Most so-called "beneficial bacteria" in gut microbiota are Gram-positive, and TLR6 recognizes the peptidoglycan (PGN) present in their cell walls. We hypothesized that a high TLR6 expression status predicts a more favorable prognosis after esophagectomy. We used an ESCC tissue microarray (TMA) to examine TLR6 expression status in ESCC patients and to determine whether TLR6 expression status correlates with prognosis after curative esophagectomy. We also examined whether PGN influences the cell proliferation activity of ESCC lines. Clinical ESCC samples from 177 patients tested for the expression of TLR6 were categorized as 3+ (n = 17), 2+ (n = 48), 1+ (n = 68), or 0 (n = 44). High TLR6 expression (3+ and 2+) correlated with significantly more favorable 5-year overall survival (OS) and disease-specific survival (DSS) after esophagectomy than a lower TLR6 expression (1+ and 0). Univariate and multivariate analyses showed that TLR6 expression status is an independent prognostic factor that affects 5-year OS. PGN significantly inhibited the cell proliferation activity of ESCC lines. This is the first study to show that high TLR6 expression status predicts a more favorable prognosis in locally advanced thoracic ESCC patients after curative esophagectomy. PGN released from "beneficial bacteria" seems to have potential to inhibit the cell proliferation activity of ESCC.

PMID:37232814 | PMC:PMC10217459 | DOI:10.3390/curroncol30050356

Biomolecules. 2023 Apr 22;13(5):720. doi: 10.3390/biom13050720.

ABSTRACT

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 Escherichia coli and the Gram-positive Bacillus subtilis. 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.

PMID:37238589 | PMC:PMC10216114 | DOI:10.3390/biom13050720