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Simpson BW, Gilmore MC, McLean AB, Cava F, Trent MS. Escherichia coli CadB is capable of promiscuously transporting muropeptides and contributing to peptidoglycan recycling. J Bacteriol 2024; 206:e0036923. [PMID: 38169298 PMCID: PMC10810205 DOI: 10.1128/jb.00369-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 12/05/2023] [Indexed: 01/05/2024] Open
Abstract
The bacterial peptidoglycan (PG) cell wall is remodeled during growth and division, releasing fragments called muropeptides. Muropeptides can be internalized and reused in a process called PG recycling. Escherichia coli is highly devoted to recycling muropeptides and is known to have at least two transporters, AmpG and OppBCDF, that import them into the cytoplasm. While studying mutants lacking AmpG, we unintentionally isolated mutations that led to the altered expression of a third transporter, CadB. CadB is normally upregulated under acidic pH conditions and is an antiporter for lysine and cadaverine. Here, we explored if CadB was altering PG recycling to assist in the absence of AmpG. Surprisingly, CadB overexpression was able to restore PG recycling when both AmpG and OppBCDF were absent. CadB was found to import freed PG peptides, a subpopulation of muropeptides, through a promiscuous activity. Altogether, our data support that CadB is a third transporter capable of contributing to PG recycling. IMPORTANCE Bacteria produce a rigid mesh cell wall. During growth, the cell wall is remodeled, which releases cell wall fragments. If released into the extracellular environment, cell wall fragments can trigger inflammation by the immune system of a host. Gastrointestinal bacteria, like Escherichia coli, have dedicated pathways to recycle almost all cell wall fragments they produce. E. coli contains two known recycling transporters, AmpG and Opp, that we previously showed are optimized for growth in different environments. Here, we identify that a third transporter, CadB, can also contribute to cell wall recycling. This work expands our understanding of cell wall recycling and highlights the dedication of organisms like E. coli to ensure high recycling in multiple growth environments.
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Affiliation(s)
- Brent W. Simpson
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Michael C. Gilmore
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, SciLifeLab, Umeå University, Umeå, Sweden
| | - Amanda Briann McLean
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, SciLifeLab, Umeå University, Umeå, Sweden
| | - M. Stephen Trent
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
- Department of Microbiology, College of Arts and Sciences, University of Georgia, Athens, Georgia, USA
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2
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Simpson BW, Gilmore MC, McLean AB, Cava F, Trent MS. Escherichia coli utilizes multiple peptidoglycan recycling permeases with distinct strategies of recycling. Proc Natl Acad Sci U S A 2023; 120:e2308940120. [PMID: 37871219 PMCID: PMC10622912 DOI: 10.1073/pnas.2308940120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Accepted: 09/27/2023] [Indexed: 10/25/2023] Open
Abstract
Bacteria produce a structural layer of peptidoglycan (PG) that enforces cell shape, resists turgor pressure, and protects the cell. As bacteria grow and divide, the existing layer of PG is remodeled and PG fragments are released. Enterics such as Escherichia coli go to great lengths to internalize and reutilize PG fragments. E. coli is estimated to break down one-third of its cell wall, yet only loses ~0 to 5% of meso-diaminopimelic acid, a PG-specific amino acid, per generation. Two transporters were identified early on to possibly be the primary permease that facilitates PG fragment recycling, i) AmpG and ii) the Opp ATP binding cassette transporter in conjunction with a PG-specific periplasmic binding protein, MppA. The contribution of each transporter to PG recycling has been debated. Here, we have found that AmpG and MppA/Opp are differentially regulated by carbon source and growth phase. In addition, MppA/Opp is uniquely capable of high-affinity scavenging of muropeptides from growth media, demonstrating that AmpG and MppA/Opp allow for different strategies of recycling PG fragments. Altogether, this work clarifies environmental contexts under which E. coli utilizes distinct permeases for PG recycling and explores how scavenging by MppA/Opp could be beneficial in mixed communities.
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Affiliation(s)
- Brent W. Simpson
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA30602
| | - Michael C. Gilmore
- Laboratory for Molecular Infection Medicine Sweden, Umeå Center for Microbial Research, Department of Molecular Biology, Umeå University, Umeå90187, Sweden
| | - Amanda Briann McLean
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA30602
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden, Umeå Center for Microbial Research, Department of Molecular Biology, Umeå University, Umeå90187, Sweden
| | - M. Stephen Trent
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA30602
- Department of Microbiology, College of Art and Sciences, University of Georgia, Athens, GA30602
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3
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Rousseau A, Michaud J, Pradeau S, Armand S, Cottaz S, Richard E, Fort S. Hijacking the Peptidoglycan Recycling Pathway of Escherichia coli to Produce Muropeptides. Chemistry 2023; 29:e202202991. [PMID: 36256497 PMCID: PMC10107939 DOI: 10.1002/chem.202202991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Indexed: 11/05/2022]
Abstract
Soluble fragments of peptidoglycan called muropeptides are released from the cell wall of bacteria as part of their metabolism or as a result of biological stresses. These compounds trigger immune responses in mammals and plants. In bacteria, they play a major role in the induction of antibiotic resistance. The development of efficient methods to produce muropeptides is, therefore, desirable both to address their mechanism of action and to design new antibacterial and immunostimulant agents. Herein, we engineered the peptidoglycan recycling pathway of Escherichia coli to produce N-acetyl-β-D-glucosaminyl-(1→4)-1,6-anhydro-N-acetyl-β-D-muramic acid (GlcNAc-anhMurNAc), a common precursor of Gram-negative and Gram-positive muropeptides. Inactivation of the hexosaminidase nagZ gene allowed the efficient production of this key disaccharide, providing access to Gram-positive muropeptides through subsequent chemical peptide conjugation. E. coli strains deficient in both NagZ hexosaminidase and amidase activities further enabled the in vivo production of Gram-negative muropeptides containing meso-diaminopimelic acid, a rarely available amino acid.
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Affiliation(s)
| | - Julie Michaud
- Univ. Grenoble Alpes, CNRS, CERMAV, 38000, Grenoble, France
| | | | - Sylvie Armand
- Univ. Grenoble Alpes, CNRS, CERMAV, 38000, Grenoble, France
| | - Sylvain Cottaz
- Univ. Grenoble Alpes, CNRS, CERMAV, 38000, Grenoble, France
| | | | - Sébastien Fort
- Univ. Grenoble Alpes, CNRS, CERMAV, 38000, Grenoble, France
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4
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Peptidoglycan recycling mediated by an ABC transporter in the plant pathogen Agrobacterium tumefaciens. Nat Commun 2022; 13:7927. [PMID: 36566216 PMCID: PMC9790009 DOI: 10.1038/s41467-022-35607-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 12/13/2022] [Indexed: 12/25/2022] Open
Abstract
During growth and division, the bacterial cell wall peptidoglycan (PG) is remodelled, resulting in the liberation of PG muropeptides which are typically reinternalized and recycled. Bacteria belonging to the Rhizobiales and Rhodobacterales orders of the Alphaproteobacteria lack the muropeptide transporter AmpG, despite having other key PG recycling enzymes. Here, we show that an alternative transporter, YejBEF-YepA, takes over this role in the Rhizobiales phytopathogen Agrobacterium tumefaciens. Muropeptide import by YejBEF-YepA governs expression of the β-lactamase AmpC in A. tumefaciens, contributing to β-lactam resistance. However, we show that the absence of YejBEF-YepA causes severe cell wall defects that go far beyond lowered AmpC activity. Thus, contrary to previously established Gram-negative models, PG recycling is vital for cell wall integrity in A. tumefaciens. YepA is widespread in the Rhizobiales and Rhodobacterales, suggesting that YejBEF-YepA-mediated PG recycling could represent an important but overlooked aspect of cell wall biology in these bacteria.
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5
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Yang X, Wang Z, Liu M, Yu X, Zhong Y, Wang F, Xu Y. Cefazolin and imipenem enhance AmpC expression and resistance in NagZ-dependent manner in Enterobacter cloacae complex. BMC Microbiol 2022; 22:284. [PMID: 36443681 PMCID: PMC9706910 DOI: 10.1186/s12866-022-02707-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 11/15/2022] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Enterobacter cloacae complex (ECC) is a common opportunistic pathogen and is responsible for causing various infections in humans. Owing to its inducible chromosomal AmpC β-lactamase (AmpC), ECC is inherently resistant to the 1st- and 2nd- generation cephalosporins. However, whether β-lactams antibiotics enhance ECC resistance remains unclear. RESULTS In this study, we found that subinhibitory concentrations (SICs) of cefazolin (CFZ) and imipenem (IMP) can advance the expression of AmpC and enhance its resistance towards β-lactams through NagZ in Enterobacter cloacae (EC). Further, AmpC manifested a substantial upregulation in EC in response to SICs of CFZ and IMP. In nagZ knockout EC (ΔnagZ), the resistance to β-lactam antibiotics was rather weakened and the effect of CFZ and IMP on AmpC induction was completely abrogated. NagZ ectopic expression can rescue the induction effects of CFZ and IMP on AmpC and increase ΔnagZ resistance. More importantly, CFZ and IMP have the potential to induce the expression of AmpR's target genes in a NagZ-dependent manner. CONCLUSIONS Our findings suggest that NagZ is a critical determinant for CFZ and IMP to promote AmpC expression and resistance and that CFZ and IMP should be used with caution since they may aggravate ECC resistance. At the same time, this study further improves our understanding of resistance mechanisms in ECC.
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Affiliation(s)
- Xianggui Yang
- grid.414880.1Department of Laboratory Medicine, Clinical Medical College and the First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan China
| | - Zhenguo Wang
- grid.414880.1Department of Stomatology, Clinical Medical College and the First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan China
| | - Mingquan Liu
- grid.414880.1Department of Laboratory Medicine, Clinical Medical College and the First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan China
| | - Xuejing Yu
- grid.267313.20000 0000 9482 7121Department of Internal Medicine, Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, TX USA
| | - Yuanxiu Zhong
- grid.413856.d0000 0004 1799 3643Department of Biotechnology, Chengdu Medical College, Chengdu, Sichuan China
| | - Fuying Wang
- grid.413856.d0000 0004 1799 3643Department of Biotechnology, Chengdu Medical College, Chengdu, Sichuan China
| | - Ying Xu
- grid.414880.1Department of Laboratory Medicine, Clinical Medical College and the First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan China
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Heydari S, Malekzadeh R, Jazayeri MH, Sarrafnejad A, Siavoshi F. Detection of peptidoglycan in yeast as a marker for the presence or abundance of intracellular Helicobacter pylori and Staphylococcus. Arch Microbiol 2022; 204:407. [PMID: 35726098 DOI: 10.1007/s00203-022-03045-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 05/21/2022] [Accepted: 05/27/2022] [Indexed: 11/26/2022]
Abstract
Peptidoglycan (PG) was targeted as the marker for bacterial occurrence inside yeast. Detection of only few bacteria in old and new generations of yeast raised the question of how yeast controls the abundance of its intracellular bacteria. One gastric C. tropicalis that showed concurrence of H. pylori and Staphylococcus 16S rDNA was stained for assessing the viability of intracellular bacteria. Fluorescein isothiocyanate (FITC)-labeled anti-PG monoclonal antibody (APGMAb) was used for detection of PG inside yeast by direct immunofluorescence. APGMAb-coated magnetic beads were used for separation of bacteria from disrupted yeasts. Bead-bound bacteria were separated, fixed, stained, and examined by scanning electron microscope (SEM). Bead-bound bacteria were cultured and identified by amplification and sequencing of 16S rDNA. Fluorescence microscopy demonstrated occurrence of few live bacteria inside yeast cells. FITC- APGMAb interacted with PG of intracellular bacteria, appearing as few green spots in mother and daughter yeast cells. Interestingly, PG fragments were also detected in the exterior of yeast cells. SEM observations showed separated bead-bound bacilli and cocci. Culture of Staphylococcus was positive. Sequencing results confirmed identity of separated bacteria as H. pylori and Staphylococcus. PG detected inside yeast may have belonged to H. pylori, Staphylococcus or any other intracellular bacteria that coexisted in yeast as its microbiome. Detection of only few intracellular bacteria in old and new generations of yeast as well as PG fragments in their exterior suggested that yeast controls the abundance of its intracellular bacteria at low rate by hydrolysis and exporting of PG.
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Affiliation(s)
- Samira Heydari
- Department of Microbiology, School of Biology, University College of Sciences, University of Tehran, Tehran, Iran
| | - Reza Malekzadeh
- Digestive Disease Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Mir Hadi Jazayeri
- Immunology Research Center, Iran University of Medical Sciences, Tehran, Iran
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Abdolfattah Sarrafnejad
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Farideh Siavoshi
- Department of Microbiology, School of Biology, University College of Sciences, University of Tehran, Tehran, Iran.
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7
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Zhang Y, Chen W, Wu D, Liu Y, Wu Z, Li J, Zhang SY, Ji Q. Molecular basis for cell-wall recycling regulation by transcriptional repressor MurR in Escherichia coli. Nucleic Acids Res 2022; 50:5948-5960. [PMID: 35640608 PMCID: PMC9177960 DOI: 10.1093/nar/gkac442] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 05/01/2022] [Accepted: 05/10/2022] [Indexed: 11/13/2022] Open
Abstract
The cell-wall recycling process is important for bacterial survival in nutrient-limited conditions and, in certain cases, is directly involved in antibiotic resistance. In the sophisticated cell-wall recycling process in Escherichia coli, the transcriptional repressor MurR controls the expression of murP and murQ, which are involved in transporting and metabolizing N-acetylmuramic acid (MurNAc), generating N-acetylmuramic acid-6-phosphate (MurNAc-6-P) and N-acetylglucosamine-6-phosphate (GlcNAc-6-P). Here, we report that both MurNAc-6-P and GlcNAc-6-P can bind to MurR and weaken the DNA binding ability of MurR. Structural characterizations of MurR in complex with MurNAc-6-P or GlcNAc-6-P as well as in the apo form revealed the detailed ligand recognition chemistries. Further studies showed that only MurNAc-6-P, but not GlcNAc-6-P, is capable of derepressing the expression of murQP controlled by MurR in cells and clarified the substrate specificity through the identification of key residues responsible for ligand binding in the complex structures. In summary, this study deciphered the molecular mechanism of the cell wall recycling process regulated by MurR in E. coli.
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Affiliation(s)
- Ya Zhang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Weizhong Chen
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Di Wu
- Shanghai Key Laboratory for Molecular Engineer of Chiral Drugs, School of Chemistry and Chemical Engineering & Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yushi Liu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Zhaowei Wu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Jian Li
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Shu-Yu Zhang
- Shanghai Key Laboratory for Molecular Engineer of Chiral Drugs, School of Chemistry and Chemical Engineering & Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Quanjiang Ji
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.,Gene Editing Center, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
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8
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Szczubiał M, Kankofer M, Wawrzykowski J, Dąbrowski R, Bochniarz M, Brodzki P. Activity of the glycosidases β-galactosidase, α-l-fucosidase, β-N-acetyl-hexosaminidase, and sialidase in uterine tissues from female dogs in diestrus with and without pyometra. Theriogenology 2022; 177:133-139. [PMID: 34700070 DOI: 10.1016/j.theriogenology.2021.10.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 10/18/2021] [Accepted: 10/18/2021] [Indexed: 01/05/2023]
Abstract
This study aimed to compare the activity of selected glycosidases (β-galactosidase, α-l-fucosidase, β-N-acetyl-hexosaminidase, and sialidase) in homogenates of uterine tissues obtained from female dogs with and without pyometra. In addition, it examined the availability of substrates for these glycosidases in the homogenates. The study was carried out on female dogs undergoing ovariohysterectomy for pyometra (n = 10) and clinically healthy dogs (n = 10) undergoing elective spaying. The activity of β-galactosidase, α-l-fucosidase, and β-N-acetyl-hexosaminidase was analyzed using a spectrofluorometer and that of sialidase using a colorimetric method. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis with Alcian Blue (AB) and Periodic Acid-Schiff (PAS) staining was performed to determine the presence of substrates for these glycosidases in the homogenates of uterine tissues. The results revealed that the activity of all the examined glycosidases was significantly higher (P < 0.05) in the uterine tissues isolated from dogs with pyometra in comparison to healthy dogs. The electrophoretic patterns of the selected samples showed several proteins, which contained different sugar moieties stained by AB and PAS and the profiles differed significantly between the pyometra group and the healthy group. Densitometric analysis of AB staining showed patterns between 233 and 148, 86 and 55, and 43 and 20 kDa, which differed markedly in sugar content between the examined groups of animals. Similarly, PAS staining analysis revealed patterns of different molecular weights, between 233 and 117 and between 55 and 32 kDa, which also differed in sugar content. These findings suggest that canine pyometra is accompanied by the increase in the activity of selected glycosidases in the uterus. This could potentially modify the glycan structures of uterine glycoproteins and in result their biological functions. Further studies are needed to elucidate the potential role of the increased activity of glycosidases in the pathogenesis of this disease.
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Affiliation(s)
- Marek Szczubiał
- Department and Clinic of Animal Reproduction, Faculty of Veterinary Medicine, University of Life Sciences, Głeboka 30, 20-612, Lublin, Poland.
| | - Marta Kankofer
- Department of Animal Biochemistry, Faculty of Veterinary Medicine, University of Life Sciences, Akademicka 12, 20-033, Lublin, Poland
| | - Jacek Wawrzykowski
- Department of Animal Biochemistry, Faculty of Veterinary Medicine, University of Life Sciences, Akademicka 12, 20-033, Lublin, Poland
| | - Roman Dąbrowski
- Department and Clinic of Animal Reproduction, Faculty of Veterinary Medicine, University of Life Sciences, Głeboka 30, 20-612, Lublin, Poland
| | - Mariola Bochniarz
- Department and Clinic of Animal Reproduction, Faculty of Veterinary Medicine, University of Life Sciences, Głeboka 30, 20-612, Lublin, Poland
| | - Piotr Brodzki
- Department and Clinic of Animal Reproduction, Faculty of Veterinary Medicine, University of Life Sciences, Głeboka 30, 20-612, Lublin, Poland
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9
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Bouquet J, Auberger N, Ashmus R, King D, Bordes A, Fontelle N, Nakagawa S, Madden Z, Proceviat C, Kato A, Désiré J, Vocadlo DJ, Blériot Y. Structural variation of the 3-acetamido-4,5,6-trihydroxyazepane iminosugar through epimerization and C-alkylation leads to low micromolar HexAB and NagZ inhibitors. Org Biomol Chem 2021; 20:619-629. [PMID: 34940771 DOI: 10.1039/d1ob02280f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the synthesis of seven-membered iminosugars derived from a 3S-acetamido-4R,5R,6S-trihydroxyazepane scaffold and their evaluation as inhibitors of functionally related exo-N-acetylhexosaminidases including human O-GlcNAcase (OGA), human lysosomal β-hexosaminidase (HexAB), and Escherichia coli NagZ. Capitalizing on the flexibility of azepanes and the active site tolerances of hexosaminidases, we explore the effects of epimerization of stereocenters at C-3, C-5 and C-6 and C-alkylation at the C-2 or C-7 positions. Accordingly, epimerization at C-6 (L-ido) and at C-5 (D-galacto) led to selective HexAB inhibitors whereas introduction of a propyl group at C-7 on the C-3 epimer furnished a potent NagZ inhibitor.
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Affiliation(s)
- J Bouquet
- Université de Poitiers, IC2MP, UMR CNRS 7285, OrgaSynth Team, Glyco group, 4 rue Michel Brunet, 86073 Poitiers cedex 09, France.
| | - N Auberger
- Université de Poitiers, IC2MP, UMR CNRS 7285, OrgaSynth Team, Glyco group, 4 rue Michel Brunet, 86073 Poitiers cedex 09, France.
| | - R Ashmus
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, V5S 1P6, Canada.
| | - D King
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, V5S 1P6, Canada.
| | - A Bordes
- Université de Poitiers, IC2MP, UMR CNRS 7285, OrgaSynth Team, Glyco group, 4 rue Michel Brunet, 86073 Poitiers cedex 09, France.
| | - N Fontelle
- Université de Poitiers, IC2MP, UMR CNRS 7285, OrgaSynth Team, Glyco group, 4 rue Michel Brunet, 86073 Poitiers cedex 09, France.
| | - S Nakagawa
- Department of Hospital Pharmacy, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
| | - Z Madden
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, V5S 1P6, Canada.
| | - C Proceviat
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, V5S 1P6, Canada.
| | - A Kato
- Department of Hospital Pharmacy, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
| | - J Désiré
- Université de Poitiers, IC2MP, UMR CNRS 7285, OrgaSynth Team, Glyco group, 4 rue Michel Brunet, 86073 Poitiers cedex 09, France.
| | - D J Vocadlo
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, V5S 1P6, Canada.
| | - Y Blériot
- Université de Poitiers, IC2MP, UMR CNRS 7285, OrgaSynth Team, Glyco group, 4 rue Michel Brunet, 86073 Poitiers cedex 09, France.
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10
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Acinetobacter baumannii Can Survive with an Outer Membrane Lacking Lipooligosaccharide Due to Structural Support from Elongasome Peptidoglycan Synthesis. mBio 2021; 12:e0309921. [PMID: 34844428 PMCID: PMC8630537 DOI: 10.1128/mbio.03099-21] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gram-negative bacteria resist external stresses due to cell envelope rigidity, which is provided by two membranes and a peptidoglycan layer. The outer membrane (OM) surface contains lipopolysaccharide (LPS; contains O-antigen) or lipooligosaccharide (LOS). LPS/LOS are essential in most Gram-negative bacteria and may contribute to cellular rigidity. Acinetobacter baumannii is a useful tool for testing these hypotheses as it can survive without LOS. Previously, our group found that strains with naturally high levels of penicillin binding protein 1A (PBP1A) could not become LOS deficient unless the gene encoding it was deleted, highlighting the relevance of peptidoglycan biosynthesis and suggesting that high PBP1A levels were toxic during LOS deficiency. Transposon sequencing and follow-up analysis found that axial peptidoglycan synthesis by the elongasome and a peptidoglycan recycling enzyme, ElsL, were vital in LOS-deficient cells. The toxicity of high PBP1A levels during LOS deficiency was clarified to be due to a negative impact on elongasome function. Our data suggest that during LOS deficiency, the strength of the peptidoglycan specifically imparted by elongasome synthesis becomes essential, supporting that the OM and peptidoglycan contribute to cell rigidity.
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11
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Désiré J, Foucart Q, Poveda A, Gourlaouen G, Shimadate Y, Kise M, Proceviat C, Ashmus R, Vocadlo DJ, Jiménez-Barbero J, Kato A, Blériot Y. Synthesis, conformational analysis and glycosidase inhibition of bicyclic nojirimycin C-glycosides based on an octahydrofuro[3,2-b]pyridine motif. Carbohydr Res 2021; 511:108491. [PMID: 34953389 DOI: 10.1016/j.carres.2021.108491] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 12/11/2021] [Accepted: 12/13/2021] [Indexed: 12/13/2022]
Abstract
A set of bicyclic iminosugar C-glycosides, based on an octahydrofuro[3,2-b]pyridine motif, has been synthesized from a C-allyl iminosugar exploiting a debenzylative iodocycloetherification and an iodine nucleophilic displacement as the key steps. The halogen allowed the introduction of a range of aglycon moieties of different sizes bearing several functionalities such as alcohol, amine, amide and triazole. In these carbohydrate mimics the fused THF ring forces the piperidine to adopt a flattened 4C1 conformation according to NMR and DFT calculations studies. In their deprotected form, these bicycles were assayed on a panel of 23 glycosidases. The iminosugars displaying hydrophobic aglycon moieties proved to be superior glycosidase inhibitors, leading to a low micromolar inhibition of human lysosome β-glucosidase (compound 11; IC50 = 2.7 μM) and rice α-glucosidase (compound 10; IC50 = 7.7 μM). Finally, the loose structural analogy of these derivatives with Thiamet G, a potent OGA bicyclic inhibitor, was illustrated by the weak OGA inhibitory activity (Ki = 140 μM) of iminosugar 5.
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Affiliation(s)
- Jérôme Désiré
- Université de Poitiers, IC2MP, UMR CNRS 7285, Equipe "Synthèse Organique", Groupe Glycochimie, 4 rue Michel Brunet, 86073, Poitiers Cedex 9, France.
| | - Quentin Foucart
- Université de Poitiers, IC2MP, UMR CNRS 7285, Equipe "Synthèse Organique", Groupe Glycochimie, 4 rue Michel Brunet, 86073, Poitiers Cedex 9, France
| | - Ana Poveda
- CIC bioGUNE, Parque technologico de Bizkaia, Edif. 801A-1°, Derio-Bizkaia 48160, and Ikerbasque, Basque Foundation for Science, Maria Lopez de Haro 3, 48013, Bilbao, Spain
| | - Gurvan Gourlaouen
- Université de Poitiers, IC2MP, UMR CNRS 7285, Equipe "Synthèse Organique", Groupe Glycochimie, 4 rue Michel Brunet, 86073, Poitiers Cedex 9, France
| | - Yuna Shimadate
- Department of Hospital Pharmacy, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Maki Kise
- Department of Hospital Pharmacy, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Cameron Proceviat
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada, V5S 1P6
| | - Roger Ashmus
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada, V5S 1P6
| | - David J Vocadlo
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada, V5S 1P6
| | - Jesús Jiménez-Barbero
- CIC bioGUNE, Parque technologico de Bizkaia, Edif. 801A-1°, Derio-Bizkaia 48160, and Ikerbasque, Basque Foundation for Science, Maria Lopez de Haro 3, 48013, Bilbao, Spain
| | - Atsushi Kato
- Department of Hospital Pharmacy, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan.
| | - Yves Blériot
- Université de Poitiers, IC2MP, UMR CNRS 7285, Equipe "Synthèse Organique", Groupe Glycochimie, 4 rue Michel Brunet, 86073, Poitiers Cedex 9, France.
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12
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Utsunomiya H, Saiki N, Kadoguchi H, Fukudome M, Hashimoto S, Ueda M, Takechi K, Takano H. Genes encoding lipid II flippase MurJ and peptidoglycan hydrolases are required for chloroplast division in the moss Physcomitrella patens. PLANT MOLECULAR BIOLOGY 2021; 107:405-415. [PMID: 33078277 DOI: 10.1007/s11103-020-01081-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 10/02/2020] [Indexed: 06/11/2023]
Abstract
Homologous genes for the peptidoglycan precursor flippase MurJ, and peptidoglycan hydrolases: lytic transglycosylase MltB, and DD-carboxypeptidase VanY are required for chloroplast division in the moss Physcomitrella patens. The moss Physcomitrella patens is used as a model plant to study plastid peptidoglycan biosynthesis. In bacteria, MurJ flippase transports peptidoglycan precursors from the cytoplasm to the periplasm. In this study, we identified a MurJ homolog (PpMurJ) in the P. patens genome. Bacteria employ peptidoglycan degradation and recycling pathways for cell division. We also searched the P. patens genome for genes homologous to bacterial peptidoglycan hydrolases and identified genes homologous for the lytic transglycosylase mltB, N-acetylglucosaminidase nagZ, and LD-carboxypeptidase ldcA in addition to a putative DD-carboxypeptidase vanY reported previously. Moreover, we found a ß-lactamase-like gene (Pplactamase). GFP fusion proteins with either PpMltB or PpVanY were detected in the chloroplasts, whereas fusion proteins with PpNagZ, PpLdcA, or Pplactamase localized in the cytoplasm. Experiments seeking PpMurJ-GFP fusion proteins failed. PpMurJ gene disruption in P. patens resulted in the appearance of macrochloroplasts in protonemal cells. Compared with the numbers of chloroplasts in wild-type plants (38.9 ± 4.9), PpMltB knockout and PpVanY knockout had lower numbers of chloroplasts (14.3 ± 6.7 and 28.1 ± 5.9, respectively). No differences in chloroplast numbers were observed after PpNagZ, PpLdcA, or Pplactamase single-knockout. Chloroplast numbers in PpMltB/PpVanY double-knockout cells were similar to those in PpMltB single-knockout cells. Zymogram analysis of the recombinant PpMltB protein revealed its peptidoglycan hydrolase activity. Our results imply that PpMurJ, PpMltB and PpVanY play a critical role in chloroplast division in the moss P. patens.
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Affiliation(s)
- Hanae Utsunomiya
- Graduate School of Science and Technology, Kumamoto University, Kumamoto, 860-8555, Japan
| | - Nozomi Saiki
- Graduate School of Science and Technology, Kumamoto University, Kumamoto, 860-8555, Japan
| | - Hayato Kadoguchi
- Faculty of Science, Kumamoto University, Kumamoto, 860-8555, Japan
| | - Masaya Fukudome
- Faculty of Science, Kumamoto University, Kumamoto, 860-8555, Japan
| | - Satomi Hashimoto
- Faculty of Science, Kumamoto University, Kumamoto, 860-8555, Japan
| | - Mami Ueda
- Faculty of Science, Kumamoto University, Kumamoto, 860-8555, Japan
| | - Katsuaki Takechi
- Faculty of Advanced Science and Technology, Kumamoto University, Kumamoto, 860-8555, Japan.
| | - Hiroyoshi Takano
- Faculty of Advanced Science and Technology, Kumamoto University, Kumamoto, 860-8555, Japan.
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13
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The fish pathogen Aliivibrio salmonicida LFI1238 can degrade and metabolize chitin despite major gene loss in the chitinolytic pathway. Appl Environ Microbiol 2021; 87:e0052921. [PMID: 34319813 DOI: 10.1128/aem.00529-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The fish pathogen Aliivibrio (Vibrio) salmonicida LFI1238 is thought to be incapable of utilizing chitin as a nutrient source since approximately half of the genes representing the chitinolytic pathway are disrupted by insertion sequences. In the present study, we combined a broad set of analytical methods to investigate this hypothesis. Cultivation studies revealed that Al. salmonicida grew efficiently on N-acetylglucosamine (GlcNAc) and chitobiose ((GlcNAc)2), the primary soluble products resulting from enzymatic chitin hydrolysis. The bacterium was also able to grow on chitin particles, albeit at a lower rate compared to the soluble substrates. The genome of the bacterium contains five disrupted chitinase genes (pseudogenes) and three intact genes encoding a glycoside hydrolase family 18 (GH18) chitinase and two auxiliary activity family 10 (AA10) lytic polysaccharide monooxygenases (LPMOs). Biochemical characterization showed that the chitinase and LPMOs were able to depolymerize both α- and β-chitin to (GlcNAc)2 and oxidized chitooligosaccharides, respectively. Notably, the chitinase displayed up to 50-fold lower activity compared to other well-studied chitinases. Deletion of the genes encoding the intact chitinolytic enzymes showed that the chitinase was important for growth on β-chitin, whereas the LPMO gene-deletion variants only showed minor growth defects on this substrate. Finally, proteomic analysis of Al. salmonicida LFI1238 growth on β-chitin showed expression of all three chitinolytic enzymes, and intriguingly also three of the disrupted chitinases. In conclusion, our results show that Al. salmonicida LFI1238 can utilize chitin as a nutrient source and that the GH18 chitinase and the two LPMOs are needed for this ability. IMPORTANCE The ability to utilize chitin as a source of nutrients is important for the survival and spread of marine microbial pathogens in the environment. One such pathogen is Aliivibrio (Vibrio) salmonicida, the causative agent of cold water vibriosis. Due to extensive gene decay, many key enzymes in the chitinolytic pathway have been disrupted, putatively rendering this bacterium incapable of chitin degradation and utilization. In the present study we demonstrate that Al. salmonicida can degrade and metabolize chitin, the most abundant biopolymer in the ocean. Our findings shed new light on the environmental adaption of this fish pathogen.
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14
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Modulation of Peptidoglycan Synthesis by Recycled Cell Wall Tetrapeptides. Cell Rep 2021; 31:107578. [PMID: 32348759 DOI: 10.1016/j.celrep.2020.107578] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 03/12/2020] [Accepted: 04/06/2020] [Indexed: 12/20/2022] Open
Abstract
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.
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15
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Garde S, Chodisetti PK, Reddy M. Peptidoglycan: Structure, Synthesis, and Regulation. EcoSal Plus 2021; 9:eESP-0010-2020. [PMID: 33470191 PMCID: PMC11168573 DOI: 10.1128/ecosalplus.esp-0010-2020] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Indexed: 02/06/2023]
Abstract
Peptidoglycan is a defining feature of the bacterial cell wall. Initially identified as a target of the revolutionary beta-lactam antibiotics, peptidoglycan has become a subject of much interest for its biology, its potential for the discovery of novel antibiotic targets, and its role in infection. Peptidoglycan is a large polymer that forms a mesh-like scaffold around the bacterial cytoplasmic membrane. Peptidoglycan synthesis is vital at several stages of the bacterial cell cycle: for expansion of the scaffold during cell elongation and for formation of a septum during cell division. It is a complex multifactorial process that includes formation of monomeric precursors in the cytoplasm, their transport to the periplasm, and polymerization to form a functional peptidoglycan sacculus. These processes require spatio-temporal regulation for successful assembly of a robust sacculus to protect the cell from turgor and determine cell shape. A century of research has uncovered the fundamentals of peptidoglycan biology, and recent studies employing advanced technologies have shed new light on the molecular interactions that govern peptidoglycan synthesis. Here, we describe the peptidoglycan structure, synthesis, and regulation in rod-shaped bacteria, particularly Escherichia coli, with a few examples from Salmonella and other diverse organisms. We focus on the pathway of peptidoglycan sacculus elongation, with special emphasis on discoveries of the past decade that have shaped our understanding of peptidoglycan biology.
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Affiliation(s)
- Shambhavi Garde
- These authors contributed equally
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India 500007
| | - Pavan Kumar Chodisetti
- These authors contributed equally
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India 500007
| | - Manjula Reddy
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India 500007
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16
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Blériot Y. Contributing to the Study of Enzymatic and Chemical Glycosyl Transfer Through the Observation and Mimicry of Glycosyl Cations. SYNTHESIS-STUTTGART 2020. [DOI: 10.1055/s-0040-1706073] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
AbstractThis account describes our efforts dedicated to: 1) the design of glycomimetics aimed at targeting therapeutically relevant carbohydrate processing enzymes, and 2) the observation, characterization, and exploitation of glycosyl cations as a tool for studying the glycosylation reaction. These findings have brought important data regarding this key ionic species as well as innovative strategies to access iminosugars of interest.1 Introduction2 The Glycosyl Cation, A Central Species in Glycosciences2.1 A Selection of the Strategies Developed so far to Gain Insights into Glycosyl Cations Structure2.2 When Superacids Meet Carbohydrates3 Chemical Probes to Gain Insights into the Pseudorotational Itinerary of Glycosides During Glycosidic Bond Hydrolysis3.1 Conformationally Locked Glycosides3.1.1 The Xylopyranose Case3.1.2 The Mannopyranose Case3.2 Conformationally Flexible Iminosugars3.2.1 Nojirimycin Ring Homologues3.2.2 Noeuromycin Ring Homologues3.2.3 Seven-Membered Iminosugar C-Glycosides4 N-Acetyl-d-glucosamine Mimics5 Ring Contraction: A Useful Tool to Increase Iminosugar’s Structural Diversity6 Regioselective Deprotection of Iminosugar C-Glycosides to Introduce Diversity at C2 Position7 Conclusion
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Xu W, Yang W, Wang Y, Wang M, Zhang M. Structural and biochemical analyses of β-N-acetylhexosaminidase Am0868 from Akkermansia muciniphila involved in mucin degradation. Biochem Biophys Res Commun 2020; 529:876-881. [PMID: 32819592 DOI: 10.1016/j.bbrc.2020.06.116] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Accepted: 06/23/2020] [Indexed: 12/30/2022]
Abstract
β-N-acetylhexosaminidases from the gut microbes are found to be capable of cleaving the specific glycoside linkages in the process of mucin degradation that has relevance for human health. However, features of the enzyme used in regulating the sugar-degrading capacities of Akkermansia muciniphila have not been well defined. Here we reported the crystal structure of a novel β-N-acetylhexosaminidase from Akkermansia muciniphila (Am0868), which displayed a typical (β/α) 8 barrel fold with a GlcNAc bound to the active center. Crystallographic and subsequent mutagenic analyses confirmed that Asp326 and Glu327 are the key catalytic residues of Am0868. Furthermore, Am0868 exhibited high specificity to β-GlcNAc supporting the substrate-assisted catalytic mechanism. Am0868 was also active in a broad pH and temperature range but inhibited strongly by metal ions Zn2+ and Cu2+. Collectively, these results indicate that Am0868 has the potential for mucin hydrolysis under some severe conditions, which highlight the superiority of A. muciniphila surviving in gut.
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Affiliation(s)
- Wenjuan Xu
- School of Life Sciences, Anhui University, Hefei, Anhui, 230601, China; Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei, Anhui, 230601, China
| | - Wenyi Yang
- School of Life Sciences, Anhui University, Hefei, Anhui, 230601, China; Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei, Anhui, 230601, China
| | - Yongzhong Wang
- School of Life Sciences, Anhui University, Hefei, Anhui, 230601, China; Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei, Anhui, 230601, China
| | - Mingzhu Wang
- School of Life Sciences, Anhui University, Hefei, Anhui, 230601, China; Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei, Anhui, 230601, China; Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui, 230601, China.
| | - Min Zhang
- School of Life Sciences, Anhui University, Hefei, Anhui, 230601, China; Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei, Anhui, 230601, China.
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18
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Abstract
The bacterial cell envelope provides many important functions. It protects cells from harsh environments, serves as a selective permeability barrier, houses bioenergetic functions, defines sensitivity to antibacterial agents, and plays a crucial role in biofilm formation, symbiosis, and virulence. Despite the important roles of this cellular compartment, we lack a detailed understanding of the biosynthesis and remodeling of the cell envelope. Here, we report that the R. sphaeroides two-component signaling system NtrYX is a previously undescribed regulator of cell envelope processes, providing evidence that it is directly involved in controlling transcription of genes involved in cell envelope assembly, structure, and function in this and possibly other bacteria. Thus, our data report on a newly discovered process used by bacteria to assemble and remodel the cell envelope. Activity of the NtrYX two-component system has been associated with important processes in diverse bacteria, ranging from symbiosis to nitrogen and energy metabolism. In the facultative alphaproteobacterium Rhodobacter sphaeroides, loss of the two-component system NtrYX results in increased lipid production and sensitivity to some known cell envelope-active compounds. In this study, we show that NtrYX directly controls multiple properties of the cell envelope. We find that the response regulator NtrX binds upstream of cell envelope genes, including those involved in peptidoglycan biosynthesis and modification and in cell division. We show that loss of NtrYX impacts the cellular levels of peptidoglycan precursors and lipopolysaccharide and alters cell envelope structure, increasing cell length and the thickness of the periplasm. Cell envelope function is also disrupted in the absence of NtrYX, resulting in increased outer membrane permeability. Based on the properties of R. sphaeroides cells lacking NtrYX and the target genes under direct control of this two-component system, we propose that NtrYX plays a previously undescribed, and potentially conserved, role in the assembly, structure, and function of the cell envelope in a variety of bacteria.
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19
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Muropeptides Stimulate Growth Resumption from Stationary Phase in Escherichia coli. Sci Rep 2019; 9:18043. [PMID: 31792329 PMCID: PMC6888817 DOI: 10.1038/s41598-019-54646-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 11/18/2019] [Indexed: 12/19/2022] Open
Abstract
When nutrients run out, bacteria enter a dormant metabolic state. This low or undetectable metabolic activity helps bacteria to preserve their scant reserves for the future needs, yet it also diminishes their ability to scan the environment for new growth-promoting substrates. However, neighboring microbial growth is a reliable indicator of a favorable environment and can thus serve as a cue for exiting dormancy. Here we report that for Escherichia coli and Pseudomonas aeruginosa this cue is provided by the basic peptidoglycan unit (i.e. muropeptide). We show that several forms of muropeptides from a variety of bacterial species can stimulate growth resumption of dormant cells and the sugar – peptide bond is crucial for this activity. These results, together with previous research that identifies muropeptides as a germination signal for bacterial spores, and their detection by mammalian immune cells, show that muropeptides are a universal cue for bacterial growth.
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20
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β-N-Acetylhexosaminidases-the wizards of glycosylation. Appl Microbiol Biotechnol 2019; 103:7869-7881. [PMID: 31401752 DOI: 10.1007/s00253-019-10065-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/23/2019] [Accepted: 07/24/2019] [Indexed: 12/27/2022]
Abstract
β-N-Acetylhexosaminidases (EC 3.2.1.52) are a unique family of glycoside hydrolases with dual substrate specificity and a particular reaction mechanism. Though hydrolytic enzymes per se, their good stability, easy recombinant production, absolute stereoselectivity, and a broad substrate specificity predestine these enzymes for challenging applications in carbohydrate synthesis. This mini-review aims to demonstrate the catalytic potential of β-N-acetylhexosaminidases in a range of unusual reactions, processing of unnatural substrates, formation of unexpected products, and demanding reaction designs. The use of unconventional media can considerably alter the progress of transglycosylation reactions. By means of site-directed mutagenesis, novel catalytic machineries can be constructed. Glycosylation of difficult substrates such as sugar nucleotides was accomplished, and the range of afforded glycosidic bonds comprises unique non-reducing sugars. Specific functional groups may be tolerated in the substrate molecule, which makes β-N-acetylhexosaminidases invaluable allies in difficult synthetic problems.
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21
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Porfírio S, Carlson RW, Azadi P. Elucidating Peptidoglycan Structure: An Analytical Toolset. Trends Microbiol 2019; 27:607-622. [DOI: 10.1016/j.tim.2019.01.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 01/16/2019] [Accepted: 01/29/2019] [Indexed: 01/04/2023]
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The hydrolase LpqI primes mycobacterial peptidoglycan recycling. Nat Commun 2019; 10:2647. [PMID: 31201321 PMCID: PMC6572805 DOI: 10.1038/s41467-019-10586-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 05/14/2019] [Indexed: 12/26/2022] Open
Abstract
Growth and division by most bacteria requires remodelling and cleavage of their cell wall. A byproduct of this process is the generation of free peptidoglycan (PG) fragments known as muropeptides, which are recycled in many model organisms. Bacteria and hosts can harness the unique nature of muropeptides as a signal for cell wall damage and infection, respectively. Despite this critical role for muropeptides, it has long been thought that pathogenic mycobacteria such as Mycobacterium tuberculosis do not recycle their PG. Herein we show that M. tuberculosis and Mycobacterium bovis BCG are able to recycle components of their PG. We demonstrate that the core mycobacterial gene lpqI, encodes an authentic NagZ β-N-acetylglucosaminidase and that it is essential for PG-derived amino sugar recycling via an unusual pathway. Together these data provide a critical first step in understanding how mycobacteria recycle their peptidoglycan. Bacterial growth and division require remodelling of the cell wall, which generates free peptidoglycan fragments. Here, Moynihan et al. show that Mycobacterium tuberculosis can recycle components of their peptidoglycan, and characterise a crucial enzyme required for this process.
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23
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Dong L, Shen S, Xu Y, Wang L, Feng R, Zhang J, Lu H. Computational Studies on the Potency and Selectivity of PUGNAc Derivatives Against GH3, GH20, and GH84 β-N-acetyl-D-hexosaminidases. Front Chem 2019; 7:235. [PMID: 31111026 PMCID: PMC6499197 DOI: 10.3389/fchem.2019.00235] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 03/25/2019] [Indexed: 02/05/2023] Open
Abstract
β-N-acetyl-D-hexosaminidases have attracted significant attention due to their crucial role in diverse physiological functions including antibacterial synergists, pathogen defense, virus infection, lysosomal storage, and protein glycosylation. In particular, the GH3 β-N-acetyl-D-hexosaminidase of V. cholerae (VcNagZ), human GH20 β-N-acetyl-D-hexosaminidase B (HsHexB), and human GH84 β-N-acetyl-D-hexosaminidase (hOGA) are three important representative glycosidases. These have been found to be implicated in β-lactam resistance (VcNagZ), lysosomal storage disorders (HsHexB) and Alzheimer's disease (hOGA). Considering the profound effects of these three enzymes, many small molecule inhibitors with good potency and selectivity have been reported to regulate the corresponding physiological functions. In this paper, the best-known inhibitors PUGNAc and two of its derivatives (N-valeryl-PUGNAc and EtBuPUG) were selected as model compounds and docked into the active pockets of VcNagZ, HsHexB, and hOGA, respectively. Subsequently, molecular dynamics simulations of the nine systems were performed to systematically compare their binding modes from active pocket architecture and individual interactions. Furthermore, the binding free energy and free energy decomposition are calculated using the MM/GBSA methods to predict the binding affinities of enzyme-inhibitor systems and to quantitatively analyze the contribution of each residue. The results show that PUGNAc is deeply-buried in the active pockets of all three enzymes, which indicates its potency (but not selectivity) against VcNagZ, HsHexB, and hOGA. However, EtBuPUG, bearing branched 2-isobutamido, adopted strained conformations and was only located in the active pocket of VcNagZ. It has completely moved out of the pocket of HsHexB and lacks interactions with HsHexB. This indicates why the selectivity of EtBuPUG to VcNagZ/HsHexB is the largest, reaching 968-fold. In addition, the contributions of the catalytic residue Asp253 (VcNagZ), Asp254 (VcNagZ), Asp175 (hOGA), and Asp354 (HsHexB) are important to distinguish the activity and selectivity of these inhibitors. The results of this study provide a helpful structural guideline to promote the development of novel and selective inhibitors against specific β-N-acetyl-D-hexosaminidases.
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Affiliation(s)
- Lili Dong
- Department of Applied Chemistry, College of Science, China Agricultural University, Beijing, China
| | - Shengqiang Shen
- Department of Applied Chemistry, College of Science, China Agricultural University, Beijing, China
| | - Yefei Xu
- Department of Applied Chemistry, College of Science, China Agricultural University, Beijing, China
| | - Leng Wang
- Department of Applied Chemistry, College of Science, China Agricultural University, Beijing, China
| | - Ruirui Feng
- Department of Applied Chemistry, College of Science, China Agricultural University, Beijing, China
| | - Jianjun Zhang
- Department of Applied Chemistry, College of Science, China Agricultural University, Beijing, China
| | - Huizhe Lu
- Department of Applied Chemistry, College of Science, China Agricultural University, Beijing, China
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Irazoki O, Hernandez SB, Cava F. Peptidoglycan Muropeptides: Release, Perception, and Functions as Signaling Molecules. Front Microbiol 2019; 10:500. [PMID: 30984120 PMCID: PMC6448482 DOI: 10.3389/fmicb.2019.00500] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 02/27/2019] [Indexed: 12/12/2022] Open
Abstract
Peptidoglycan (PG) is an essential molecule for the survival of bacteria, and thus, its biosynthesis and remodeling have always been in the spotlight when it comes to the development of antibiotics. The peptidoglycan polymer provides a protective function in bacteria, but at the same time is continuously subjected to editing activities that in some cases lead to the release of peptidoglycan fragments (i.e., muropeptides) to the environment. Several soluble muropeptides have been reported to work as signaling molecules. In this review, we summarize the mechanisms involved in muropeptide release (PG breakdown and PG recycling) and describe the known PG-receptor proteins responsible for PG sensing. Furthermore, we overview the role of muropeptides as signaling molecules, focusing on the microbial responses and their functions in the host beyond their immunostimulatory activity.
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Affiliation(s)
| | | | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
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25
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Wang M, Zheng F, Wang T, Lyu YM, Alteen MG, Cai ZP, Cui ZL, Liu L, Voglmeir J. Characterization of Stackebrandtia nassauensis GH 20 Beta-Hexosaminidase, a Versatile Biocatalyst for Chitobiose Degradation. Int J Mol Sci 2019; 20:ijms20051243. [PMID: 30871033 PMCID: PMC6429369 DOI: 10.3390/ijms20051243] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 02/21/2019] [Accepted: 03/04/2019] [Indexed: 12/31/2022] Open
Abstract
An unstudied β-N-acetylhexosaminidase (SnHex) from the soil bacterium Stackebrandtia nassauensis was successfully cloned and subsequently expressed as a soluble protein in Escherichia coli. Activity tests and the biochemical characterization of the purified protein revealed an optimum pH of 6.0 and a robust thermal stability at 50 °C within 24 h. The addition of urea (1 M) or sodium dodecyl sulfate (1% w/v) reduced the activity of the enzyme by 44% and 58%, respectively, whereas the addition of divalent metal ions had no effect on the enzymatic activity. PUGNAc (O-(2-acetamido-2-deoxy-D-glucopyranosylidene)amino-N-phenylcarbamate) strongly inhibited the enzyme in sub-micromolar concentrations. The β-N-acetylhexosaminidase was able to hydrolyze β1,2-linked, β1,3-linked, β1,4-linked, and β1,6-linked GlcNAc residues from the non-reducing end of various tested glycan standards, including bisecting GlcNAc from one of the tested hybrid-type N-glycan substrates. A mutational study revealed that the amino acids D306 and E307 bear the catalytically relevant side acid/base side chains. When coupled with a chitinase, the β-N-acetylhexosaminidase was able to generate GlcNAc directly from colloidal chitin, which showed the potential of this enzyme for biotechnological applications.
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Affiliation(s)
- Meng Wang
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
| | - Feng Zheng
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
| | - Ting Wang
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
| | - Yong-Mei Lyu
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
| | - Matthew G Alteen
- Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada.
| | - Zhi-Peng Cai
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
| | - Zhong-Li Cui
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
| | - Li Liu
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
| | - Josef Voglmeir
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
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26
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Chen X, Wang J, Liu M, Yang W, Wang Y, Tang R, Zhang M. Crystallographic evidence for substrate-assisted catalysis of β-N-acetylhexosaminidas from Akkermansia muciniphila. Biochem Biophys Res Commun 2019; 511:833-839. [PMID: 30846208 DOI: 10.1016/j.bbrc.2019.02.074] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 02/14/2019] [Indexed: 12/21/2022]
Abstract
β-N-acetylhexosaminidases from Akkermansia muciniphila was reported to perform the crystal structure with GlcNAc complex, which proved to be the substrate of Am2301. Domain II of Am2301 is consisted of amino acid residues 111-489 and is folded as a (β/α)8 barrel with the active site combined of the glycosyl hydrolases. Crystallographic evidence showed that Asp-278 and Glu-279 could be the catalytic site and Tyr-373 may plays a role on binding the substrate. Moreover, Am2301 prefers to bind Zn ion, which similar to other GH 20 family. Enzyme activity and kinetic parameters of wild-type Am2301 and mutants proved that Asp-278 and Glu-279 are the catalytic sites and they play a critical role on the catalytic process. Overall, our results demonstrate that Am2301 and its complex with GlcNAC provide obvious structural evidence for substrate-assisted catalysis. Obviously, this expands our understanding on the mode of substrate-assisted reaction for this enzyme family in Akkermansia muciniphila.
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Affiliation(s)
- Xi Chen
- School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei, Anhui, 230601, China; Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, 111 Jiulong Road, Hefei, Anhui, 230601, China; Department of Biological and Food Engineering, Bozhou University, 2266 Tangwang Road, Bozhou, Anhui, China
| | - Junchao Wang
- School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei, Anhui, 230601, China; Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, 111 Jiulong Road, Hefei, Anhui, 230601, China
| | - Mingjie Liu
- School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei, Anhui, 230601, China; Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, 111 Jiulong Road, Hefei, Anhui, 230601, China
| | - Wenyi Yang
- School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei, Anhui, 230601, China; Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, 111 Jiulong Road, Hefei, Anhui, 230601, China
| | - Yongzhong Wang
- School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei, Anhui, 230601, China; Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, 111 Jiulong Road, Hefei, Anhui, 230601, China
| | - Rupei Tang
- School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei, Anhui, 230601, China.
| | - Min Zhang
- School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei, Anhui, 230601, China; Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, 111 Jiulong Road, Hefei, Anhui, 230601, China.
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27
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Vermassen A, Leroy S, Talon R, Provot C, Popowska M, Desvaux M. Cell Wall Hydrolases in Bacteria: Insight on the Diversity of Cell Wall Amidases, Glycosidases and Peptidases Toward Peptidoglycan. Front Microbiol 2019; 10:331. [PMID: 30873139 PMCID: PMC6403190 DOI: 10.3389/fmicb.2019.00331] [Citation(s) in RCA: 179] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 02/08/2019] [Indexed: 11/13/2022] Open
Abstract
The cell wall (CW) of bacteria is an intricate arrangement of macromolecules, at least constituted of peptidoglycan (PG) but also of (lipo)teichoic acids, various polysaccharides, polyglutamate and/or proteins. During bacterial growth and division, there is a constant balance between CW degradation and biosynthesis. The CW is remodeled by bacterial hydrolases, whose activities are carefully regulated to maintain cell integrity or lead to bacterial death. Each cell wall hydrolase (CWH) has a specific role regarding the PG: (i) cell wall amidase (CWA) cleaves the amide bond between N-acetylmuramic acid and L-alanine residue at the N-terminal of the stem peptide, (ii) cell wall glycosidase (CWG) catalyses the hydrolysis of the glycosidic linkages, whereas (iii) cell wall peptidase (CWP) cleaves amide bonds between amino acids within the PG chain. After an exhaustive overview of all known conserved catalytic domains responsible for CWA, CWG, and CWP activities, this review stresses that the CWHs frequently display a modular architecture combining multiple and/or different catalytic domains, including some lytic transglycosylases as well as CW binding domains. From there, direct physiological and collateral roles of CWHs in bacterial cells are further discussed.
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Affiliation(s)
- Aurore Vermassen
- Université Clermont Auvergne, INRA, MEDiS, Clermont-Ferrand, France
| | - Sabine Leroy
- Université Clermont Auvergne, INRA, MEDiS, Clermont-Ferrand, France
| | - Régine Talon
- Université Clermont Auvergne, INRA, MEDiS, Clermont-Ferrand, France
| | | | - Magdalena Popowska
- Department of Applied Microbiology, Faculty of Biology, Institute of Microbiology, University of Warsaw, Warsaw, Poland
| | - Mickaël Desvaux
- Université Clermont Auvergne, INRA, MEDiS, Clermont-Ferrand, France
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28
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Jiang S, Jiang H, Zhou Y, Jiang S, Zhang G. High-level expression of β-N-Acetylglucosaminidase BsNagZ in Pichia pastoris to obtain GlcNAc. Bioprocess Biosyst Eng 2019; 42:611-619. [DOI: 10.1007/s00449-018-02067-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Accepted: 12/21/2018] [Indexed: 01/11/2023]
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29
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Oliveira ESD, Junges Â, Sbaraini N, Andreis FC, Thompson CE, Staats CC, Schrank A. Molecular evolution and transcriptional profile of GH3 and GH20 β-N-acetylglucosaminidases in the entomopathogenic fungus Metarhizium anisopliae. Genet Mol Biol 2018; 41:843-857. [PMID: 30534852 PMCID: PMC6415606 DOI: 10.1590/1678-4685-gmb-2017-0363] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 02/23/2018] [Indexed: 01/15/2023] Open
Abstract
Cell walls are involved in manifold aspects of fungi maintenance. For several fungi, chitin synthesis, degradation and recycling are essential processes required for cell wall biogenesis; notably, the activity of β-N-acetylglucosaminidases (NAGases) must be present for chitin utilization. For entomopathogenic fungi, such as Metarhizium anisopliae, chitin degradation is also used to breach the host cuticle during infection. In view of the putative role of NAGases as virulence factors, this study explored the transcriptional profile and evolution of putative GH20 NAGases (MaNAG1 and MaNAG2) and GH3 NAGases (MaNAG3 and MaNAG4) identified in M. anisopliae. While MaNAG2 orthologs are conserved in several ascomycetes, MaNAG1 clusters only with Aspergilllus sp. and entomopathogenic fungal species. By contrast, MaNAG3 and MaNAG4 were phylogenetically related with bacterial GH3 NAGases. The transcriptional profiles of M. anisopliae NAGase genes were evaluated in seven culture conditions showing no common regulatory patterns, suggesting that these enzymes may have specific roles during the Metarhizium life cycle. Moreover, the expression of MaNAG3 and MaNAG4 regulated by chitinous substrates is the first evidence of the involvement of putative GH3 NAGases in physiological cell processes in entomopathogens, indicating their potential influence on cell differentiation during the M. anisopliae life cycle.
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Affiliation(s)
- Eder Silva de Oliveira
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Ângela Junges
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Nicolau Sbaraini
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Fábio Carrer Andreis
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | | | | | - Augusto Schrank
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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Ho LA, Winogrodzki JL, Debowski AW, Madden Z, Vocadlo DJ, Mark BL, Stubbs KA. A mechanism-based GlcNAc-inspired cyclophellitol inactivator of the peptidoglycan recycling enzyme NagZ reverses resistance to β-lactams in Pseudomonas aeruginosa. Chem Commun (Camb) 2018; 54:10630-10633. [PMID: 30178799 DOI: 10.1039/c8cc05281f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The development of a potent mechanism-based inactivator of NagZ, an enzyme critical to the production of inducible AmpC β-lactamase in Gram-negative bacteria, is presented. This inactivator significantly reduces MIC values for important β-lactams against a clinically relevant strain of Pseudomonas aeruginosa.
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Affiliation(s)
- Louisa A Ho
- School of Molecular Sciences, University of Western Australia, Crawley, WA 6009, Australia.
| | - Judith L Winogrodzki
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba R3T2N2, Canada.
| | - Aleksandra W Debowski
- School of Molecular Sciences, University of Western Australia, Crawley, WA 6009, Australia. and School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia
| | - Zarina Madden
- Department of Chemistry, Simon Fraser University, Burnaby, BC V5A1S6, Canada
| | - David J Vocadlo
- Department of Chemistry, Simon Fraser University, Burnaby, BC V5A1S6, Canada
| | - Brian L Mark
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba R3T2N2, Canada.
| | - Keith A Stubbs
- School of Molecular Sciences, University of Western Australia, Crawley, WA 6009, Australia.
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31
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Dik DA, Fisher JF, Mobashery S. Cell-Wall Recycling of the Gram-Negative Bacteria and the Nexus to Antibiotic Resistance. Chem Rev 2018; 118:5952-5984. [PMID: 29847102 PMCID: PMC6855303 DOI: 10.1021/acs.chemrev.8b00277] [Citation(s) in RCA: 130] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The importance of the cell wall to the viability of the bacterium is underscored by the breadth of antibiotic structures that act by blocking key enzymes that are tasked with cell-wall creation, preservation, and regulation. The interplay between cell-wall integrity, and the summoning forth of resistance mechanisms to deactivate cell-wall-targeting antibiotics, involves exquisite orchestration among cell-wall synthesis and remodeling and the detection of and response to the antibiotics through modulation of gene regulation by specific effectors. Given the profound importance of antibiotics to the practice of medicine, the assertion that understanding this interplay is among the most fundamentally important questions in bacterial physiology is credible. The enigmatic regulation of the expression of the AmpC β-lactamase, a clinically significant and highly regulated resistance response of certain Gram-negative bacteria to the β-lactam antibiotics, is the exemplar of this challenge. This review gives a current perspective to this compelling, and still not fully solved, 35-year enigma.
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Affiliation(s)
- David A. Dik
- Department of Chemistry and Biochemistry, McCourtney Hall, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Jed F. Fisher
- Department of Chemistry and Biochemistry, McCourtney Hall, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Shahriar Mobashery
- Department of Chemistry and Biochemistry, McCourtney Hall, University of Notre Dame, Notre Dame, Indiana 46556, United States
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Isolation and Evaluation of New Antagonist Bacillus Strains for the Control of Pathogenic and Mycotoxigenic Fungi of Fig Orchards. Appl Biochem Biotechnol 2018; 186:692-711. [PMID: 29721823 DOI: 10.1007/s12010-018-2764-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 04/16/2018] [Indexed: 10/17/2022]
Abstract
Bacillus is an antagonistic bacteria that shows high effectiveness against different phytopathogenic fungi and produces various lytic enzymes, such as chitosanase, chitinase, protease, and gluconase. The aim of this study is to determine Bacillus spp. for lytic enzyme production and to evaluate the antifungal effects of the selected strains for biocontrol of mycotoxigenic and phytopathogenic fungi. A total of 92 endospore-forming bacterial isolates from the 24 fig orchard soil samples were screened for chitosanase production, and six best chitosanolytic isolates were selected to determine chitinase, protease, and N-acetyl-β-hexosaminidase activity and molecularly identified. The antagonistic activities of six Bacillus strains against Aspergillus niger EGE-K-213, Aspergillus foetidus EGE-K-211, Aspergillus ochraceus EGE-K-217, and Fusarium solani KCTC 6328 were evaluated. Fungal spore germination inhibition and biomass inhibition activities were also measured against A. niger EGE-K-213. The results demonstrated that Bacillus mojavensis EGE-B-5.2i and Bacillus thuringiensis EGE-B-14.1i were more efficient antifungal agents against A. niger EGE-K-213. B. mojavensis EGE-B-5.2i has shown maximum inhibition of the biomass (30.4%), and B. thuringiensis EGE-B-14.1i has shown maximum inhibition of spore germination (33.1%) at 12 h. This is the first study reporting the potential of antagonist Bacillus strains as biocontrol agents against mycotoxigenic fungi of fig orchads.
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33
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Juan C, Torrens G, González-Nicolau M, Oliver A. Diversity and regulation of intrinsic β-lactamases from non-fermenting and other Gram-negative opportunistic pathogens. FEMS Microbiol Rev 2018; 41:781-815. [PMID: 29029112 DOI: 10.1093/femsre/fux043] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 08/18/2017] [Indexed: 01/22/2023] Open
Abstract
This review deeply addresses for the first time the diversity, regulation and mechanisms leading to mutational overexpression of intrinsic β-lactamases from non-fermenting and other non-Enterobacteriaceae Gram-negative opportunistic pathogens. After a general overview of the intrinsic β-lactamases described so far in these microorganisms, including circa. 60 species and 100 different enzymes, we review the wide array of regulatory pathways of these β-lactamases. They include diverse LysR-type regulators, which control the expression of β-lactamases from relevant nosocomial pathogens such as Pseudomonas aeruginosa or Stenothrophomonas maltophilia or two-component regulators, with special relevance in Aeromonas spp., along with other pathways. Likewise, the multiple mutational mechanisms leading to β-lactamase overexpression and β-lactam resistance development, including AmpD (N-acetyl-muramyl-L-alanine amidase), DacB (PBP4), MrcA (PPBP1A) and other PBPs, BlrAB (two-component regulator) or several lytic transglycosylases among others, are also described. Moreover, we address the growing evidence of a major interplay between β-lactamase regulation, peptidoglycan metabolism and virulence. Finally, we analyse recent works showing that blocking of peptidoglycan recycling (such as inhibition of NagZ or AmpG) might be useful to prevent and revert β-lactam resistance. Altogether, the provided information and the identified gaps should be valuable for guiding future strategies for combating multidrug-resistant Gram-negative pathogens.
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Affiliation(s)
- Carlos Juan
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases-Instituto de Investigación Sanitaria de Baleares (IdISBa), 07120 Palma, Illes Balears, Spain
| | - Gabriel Torrens
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases-Instituto de Investigación Sanitaria de Baleares (IdISBa), 07120 Palma, Illes Balears, Spain
| | - Mar González-Nicolau
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases-Instituto de Investigación Sanitaria de Baleares (IdISBa), 07120 Palma, Illes Balears, Spain
| | - Antonio Oliver
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases-Instituto de Investigación Sanitaria de Baleares (IdISBa), 07120 Palma, Illes Balears, Spain
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34
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Wang M, Zhang XY, Guo RR, Cai ZP, Hu XC, Chen H, Wei S, Voglmeir J, Liu L. Cloning, purification and biochemical characterization of two β- N -acetylhexosaminidases from the mucin-degrading gut bacterium Akkermansia muciniphila. Carbohydr Res 2018; 457:1-7. [DOI: 10.1016/j.carres.2017.12.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 12/13/2017] [Accepted: 12/18/2017] [Indexed: 12/15/2022]
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35
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Dhar S, Kumari H, Balasubramanian D, Mathee K. Cell-wall recycling and synthesis in Escherichia coli and Pseudomonas aeruginosa – their role in the development of resistance. J Med Microbiol 2018; 67:1-21. [DOI: 10.1099/jmm.0.000636] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Affiliation(s)
- Supurna Dhar
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | - Hansi Kumari
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | | | - Kalai Mathee
- Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
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36
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Impacts of Penicillin Binding Protein 2 Inactivation on β-Lactamase Expression and Muropeptide Profile in Stenotrophomonas maltophilia. mSystems 2017; 2:mSystems00077-17. [PMID: 28861525 PMCID: PMC5574705 DOI: 10.1128/msystems.00077-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 07/28/2017] [Indexed: 12/05/2022] Open
Abstract
Inducible expression of chromosomally encoded β-lactamase(s) is a key mechanism for β-lactam resistance in Enterobacter cloacae, Citrobacter freundii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. The muropeptides produced during the peptidoglycan recycling pathway act as activator ligands for β-lactamase(s) induction. The muropeptides 1,6-anhydromuramyl pentapeptide and 1,6-anhydromuramyl tripeptide are the known activator ligands for ampC β-lactamase expression in E. cloacae. Here, we dissected the type of muropepetides for L1/L2 β-lactamase expression in an mrdA deletion mutant of S. maltophilia. Distinct from the findings with the ampC system, 1,6-anhydromuramyl tetrapeptide is the candidate for ΔmrdA-mediated β-lactamase expression in S. maltophilia. Our work extends the understanding of β-lactamase induction and provides valuable information for combating the occurrence of β-lactam resistance. Penicillin binding proteins (PBPs) are involved in peptidoglycan synthesis, and their inactivation is linked to β-lactamase expression in ampR–β-lactamase module–harboring Gram-negative bacteria. There are seven annotated PBP genes, namely, mrcA, mrcB, pbpC, mrdA, ftsI, dacB, and dacC, in the Stenotrophomonas maltophilia genome, and these genes encode PBP1a, PBP1b, PBP1c, PBP2, PBP3, PBP4, and PBP6, respectively. In addition, S. maltophilia harbors two β-lactamase genes, L1 and L2, whose expression is induced via β-lactam challenge. The impact of PBP inactivation on L1/L2 expression was assessed in this study. Inactivation of mrdA resulted in increased L1/L2 expression in the absence of β-lactam challenge, and the underlying mechanism was further elucidated. The roles of ampNG, ampDI (the homologue of Escherichia coli ampD), nagZ, ampR, and creBC in L1/L2 expression mediated by a ΔmrdA mutant strain were assessed via mutant construction and β-lactamase activity determinations. Furthermore, the strain ΔmrdA-mediated change in the muropeptide profile was assessed using liquid chromatography mass spectrometry (LC-MS). The mutant ΔmrdA-mediated L1/L2 expression relied on functional AmpNG, AmpR, and NagZ, was restricted by AmpDI, and was less related to the CreBC two-component system. Inactivation of mrdA significantly increased the levels of total and periplasmic N-acetylglucosaminyl-1,6-anhydro-N-acetylmuramyl-l-alanyl-d-glutamyl-meso-diamnopimelic acid-d-alanine (GlcNAc-anhMurNAc tetrapeptide, or M4N), supporting that the critical activator ligands for mutant strain ΔmrdA-mediated L1/L2 expression are anhMurNAc tetrapeptides. IMPORTANCE Inducible expression of chromosomally encoded β-lactamase(s) is a key mechanism for β-lactam resistance in Enterobacter cloacae, Citrobacter freundii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. The muropeptides produced during the peptidoglycan recycling pathway act as activator ligands for β-lactamase(s) induction. The muropeptides 1,6-anhydromuramyl pentapeptide and 1,6-anhydromuramyl tripeptide are the known activator ligands for ampC β-lactamase expression in E. cloacae. Here, we dissected the type of muropepetides for L1/L2 β-lactamase expression in an mrdA deletion mutant of S. maltophilia. Distinct from the findings with the ampC system, 1,6-anhydromuramyl tetrapeptide is the candidate for ΔmrdA-mediated β-lactamase expression in S. maltophilia. Our work extends the understanding of β-lactamase induction and provides valuable information for combating the occurrence of β-lactam resistance.
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37
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Vadlamani G, Stubbs KA, Désiré J, Blériot Y, Vocadlo DJ, Mark BL. Conformational flexibility of the glycosidase NagZ allows it to bind structurally diverse inhibitors to suppress β-lactam antibiotic resistance. Protein Sci 2017; 26:1161-1170. [PMID: 28370529 DOI: 10.1002/pro.3166] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Revised: 03/22/2017] [Accepted: 03/23/2017] [Indexed: 11/10/2022]
Abstract
NagZ is an N-acetyl-β-d-glucosaminidase that participates in the peptidoglycan (PG) recycling pathway of Gram-negative bacteria by removing N-acetyl-glucosamine (GlcNAc) from PG fragments that have been excised from the cell wall during growth. The 1,6-anhydromuramoyl-peptide products generated by NagZ activate β-lactam resistance in many Gram-negative bacteria by inducing the expression of AmpC β-lactamase. Blocking NagZ activity can thereby suppress β-lactam antibiotic resistance in these bacteria. The NagZ active site is dynamic and it accommodates distortion of the glycan substrate during catalysis using a mobile catalytic loop that carries a histidine residue which serves as the active site general acid/base catalyst. Here, we show that flexibility of this catalytic loop also accommodates structural differences in small molecule inhibitors of NagZ, which could be exploited to improve inhibitor specificity. X-ray structures of NagZ bound to the potent yet non-selective N-acetyl-β-glucosaminidase inhibitor PUGNAc (O-(2-acetamido-2-deoxy-d-glucopyranosylidene) amino-N-phenylcarbamate), and two NagZ-selective inhibitors - EtBuPUG, a PUGNAc derivative bearing a 2-N-ethylbutyryl group, and MM-156, a 3-N-butyryl trihydroxyazepane, revealed that the phenylcarbamate moiety of PUGNAc and EtBuPUG completely displaces the catalytic loop from the NagZ active site to yield a catalytically incompetent form of the enzyme. In contrast, the catalytic loop was found positioned in the catalytically active conformation within the NagZ active site when bound to MM-156, which lacks the phenylcarbamate extension. Displacement of the catalytic loop by PUGNAc and its N-acyl derivative EtBuPUG alters the active site conformation of NagZ, which presents an additional strategy to improve the potency and specificity of NagZ inhibitors.
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Affiliation(s)
- Grishma Vadlamani
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada, R3T2N2
| | - Keith A Stubbs
- School of Molecular Sciences, University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Jérôme Désiré
- IC2MP, UMR CNRS 7285, Équipe "Synthèse Organique" Groupe Glycochimie, Université de Poitiers, 4 rue Michel Brunet, 86073, Poitiers cedex 9, France
| | - Yves Blériot
- IC2MP, UMR CNRS 7285, Équipe "Synthèse Organique" Groupe Glycochimie, Université de Poitiers, 4 rue Michel Brunet, 86073, Poitiers cedex 9, France
| | - David J Vocadlo
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada, V5S 1P6
| | - Brian L Mark
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada, R3T2N2
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Identification of MupP as a New Peptidoglycan Recycling Factor and Antibiotic Resistance Determinant in Pseudomonas aeruginosa. mBio 2017; 8:mBio.00102-17. [PMID: 28351916 PMCID: PMC5371409 DOI: 10.1128/mbio.00102-17] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Peptidoglycan (PG) is an essential cross-linked polymer that surrounds most bacterial cells to prevent osmotic rupture of the cytoplasmic membrane. Its synthesis relies on penicillin-binding proteins, the targets of beta-lactam antibiotics. Many Gram-negative bacteria, including the opportunistic pathogen Pseudomonas aeruginosa, are resistant to beta-lactams because of a chromosomally encoded beta-lactamase called AmpC. In P. aeruginosa, expression of the ampC gene is tightly regulated and its induction is linked to cell wall stress. We reasoned that a reporter gene fusion to the ampC promoter would allow us to identify mutants defective in maintaining cell wall homeostasis and thereby uncover new factors involved in the process. A library of transposon-mutagenized P. aeruginosa was therefore screened for mutants with elevated ampC promoter activity. As an indication that the screen was working as expected, mutants with transposons disrupting the dacB gene were isolated. Defects in DacB have previously been implicated in ampC induction and clinical resistance to beta-lactam antibiotics. The screen also uncovered murU and PA3172 mutants that, upon further characterization, displayed nearly identical drug resistance and sensitivity profiles. We present genetic evidence that PA3172, renamed mupP, encodes the missing phosphatase predicted to function in the MurU PG recycling pathway that is widely distributed among Gram-negative bacteria. The cell wall biogenesis pathway is the target of many of our best antibiotics, including penicillin and related beta-lactam drugs. Resistance to these therapies is on the rise, particularly among Gram-negative species like Pseudomonas aeruginosa, a problematic opportunistic pathogen. To better understand how these organisms resist cell wall-targeting antibiotics, we screened for P. aeruginosa mutants defective in maintaining cell wall homeostasis. The screen identified a new factor, called MupP, involved in the recycling of cell wall turnover products. Characterization of MupP and other components of the pathway revealed that cell wall recycling plays important roles in both the resistance and the sensitivity of P. aeruginosa to cell wall-targeting antibiotics.
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Carbohydrate recognition and lysis by bacterial peptidoglycan hydrolases. Curr Opin Struct Biol 2017; 44:87-100. [PMID: 28109980 DOI: 10.1016/j.sbi.2017.01.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 12/23/2016] [Accepted: 01/02/2017] [Indexed: 01/26/2023]
Abstract
The major component of bacterial cell wall is peptidoglycan (PG), a complex polymer formed by long glycan chains cross-linked by peptide stems. PG is in constant equilibrium requiring well-orchestrated coordination between synthesis and degradation. The resulting cell-wall fragments can be recycled, act as messengers for bacterial communication, as effector molecules in immune response or as signaling molecules triggering antibiotics resistance. Tailoring and recycling of PG requires the cleavage of different covalent bonds of the PG sacculi by a diverse set of specific enzymes whose activities are strictly regulated. Here, we review the molecular mechanisms that govern PG remodeling focusing on the structural information available for the bacterial lytic enzymes and the mechanisms by which they recognize their substrates.
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Hamou-Segarra M, Zamorano L, Vadlamani G, Chu M, Sanchez-Diener I, Juan C, Blazquez J, Hattie M, Stubbs KA, Mark BL, Oliver A. Synergistic activity of fosfomycin, β-lactams and peptidoglycan recycling inhibition againstPseudomonas aeruginosa. J Antimicrob Chemother 2016; 72:448-454. [DOI: 10.1093/jac/dkw456] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 09/22/2016] [Accepted: 09/25/2016] [Indexed: 01/26/2023] Open
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Dangi AK, Rishi P, Tewari R. Enhancing the Yield of Active Recombinant Chitobiase by Physico-Chemical and In Vitro Refolding Studies. Protein J 2016; 35:72-9. [PMID: 26831864 DOI: 10.1007/s10930-016-9648-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Chitobiase (CHB) is an important enzyme for the production of N-acetyl-D-glucosamine from the chitin biopolymer in the series of chitinolytic enzymes. Majority of over-expressed CHB (58%) in E. coli expression system led to formation of inclusion bodies. The production and soluble yield of active CHB was enhanced by co-expression with GroEL/ES chaperonin, optimizing culture conditions and solubilization followed by refolding of remaining inactive chitobiase present in the form of inclusion bodies. The growth of recombinant E. coli produced 42% CHB in soluble form and the rest (~58%) as inclusion bodies. The percentage of active CHB was enhanced to 71% by co-expression with GroEL/ES chaperonin system and optimizing culture conditions (37 °C, 200 rpm, IPTG--0.5 mM, L-arabinose--13.2 mM). Of the remaining inactive CHB present in inclusion bodies, 37% could be recovered in active form using pulsatile dilution method involving denaturants (2 M urea, pH 12.5) and protein refolding studies (1.0 M L-arginine, 5% glycerol). Using combinatorial approach, 80% of the total CHB expressed, could be recovered from cells grown in one litre of LB medium is a step forward in replacing hazardous chemical technology by biotechnological process for the production of NAG from chitinous waste.
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Affiliation(s)
- Arun Kumar Dangi
- Department of Microbial Biotechnology, Panjab University, Sector 14, Chandigarh, 160014, India.
| | - Praveen Rishi
- Department of Microbiology, Panjab University, Chandigarh, India.
| | - Rupinder Tewari
- Department of Microbial Biotechnology, Panjab University, Sector 14, Chandigarh, 160014, India.
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Su C, Lu Y, Liu H. N-acetylglucosamine sensing by a GCN5-related N-acetyltransferase induces transcription via chromatin histone acetylation in fungi. Nat Commun 2016; 7:12916. [PMID: 27694804 PMCID: PMC5063960 DOI: 10.1038/ncomms12916] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 08/16/2016] [Indexed: 12/11/2022] Open
Abstract
N-acetylglucosamine (GlcNAc) exists ubiquitously as a component of the surface on a wide range of cells, from bacteria to humans. Many fungi are able to utilize environmental GlcNAc to support growth and induce cellular development, a property important for their survival in various host niches. However, how the GlcNAc signal is sensed and subsequently transduced is largely unknown. Here, we identify a gene that is essential for GlcNAc signalling (NGS1) in Candida albicans, a commensal and pathogenic yeast of humans. Ngs1 can bind GlcNAc through the N-terminal β-N-acetylglucosaminidase homology domain. This binding activates N-acetyltransferase activity in the C-terminal GCN5-related N-acetyltransferase domain, which is required for GlcNAc-induced promoter histone acetylation and transcription. Ngs1 is targeted to the promoters of GlcNAc-inducible genes constitutively by the transcription factor Rep1. Ngs1 is conserved in diverse fungi that have GlcNAc catabolic genes. Thus, fungi use Ngs1 as a GlcNAc-sensor and transducer for GlcNAc-induced transcription. Many fungi are able to metabolise environmental N-acetylglucosamine, however the mechanism by which this molecule is sensed is unclear. Su and Lu et al. show that Candida albicans NGS1 fulfils this function by mediating N-acetylglucosamine-dependent histone acetylation at target genes.
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Affiliation(s)
- Chang Su
- Department of Biological Chemistry, University of California, Irvine, California 92697, USA
| | - Yang Lu
- Department of Biological Chemistry, University of California, Irvine, California 92697, USA
| | - Haoping Liu
- Department of Biological Chemistry, University of California, Irvine, California 92697, USA
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Perley-Robertson GE, Yadav AK, Winogrodzki JL, Stubbs KA, Mark BL, Vocadlo DJ. A Fluorescent Transport Assay Enables Studying AmpG Permeases Involved in Peptidoglycan Recycling and Antibiotic Resistance. ACS Chem Biol 2016; 11:2626-35. [PMID: 27442597 DOI: 10.1021/acschembio.6b00552] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Inducible AmpC β-lactamases deactivate a broad-spectrum of β-lactam antibiotics and afford antibiotic resistance in many Gram-negative bacteria. The disturbance of peptidoglycan recycling caused by β-lactam antibiotics leads to accumulation of GlcNAc-1,6-anhydroMurNAc-peptides, which are transported by AmpG to the cytoplasm where they are processed into AmpC inducers. AmpG transporters are poorly understood; however, their loss restores susceptibility toward β-lactam antibiotics, highlighting AmpG as a potential target for resistance-attenuating therapeutics. We prepare a GlcNAc-1,6-anhydroMurNAc-fluorophore conjugate and, using live E. coli spheroplasts, quantitatively analyze its transport by AmpG and inhibition of this process by a competing substrate. Further, we use this transport assay to evaluate the function of two AmpG homologues from Pseudomonas aeruginosa and show that P. aeruginosa AmpG (Pa-AmpG) but not AmpP (Pa-AmpP) transports this probe substrate. We corroborate these results by AmpC induction assays with Pa-AmpG and Pa-AmpP. This fluorescent AmpG probe and spheroplast-based transport assay will enable improved understanding of PG recycling and of permeases from the major facilitator superfamily of transport proteins and may aid in identification of AmpG antagonists that combat AmpC-mediated resistance toward β-lactam antibiotics.
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Affiliation(s)
| | - Anuj K. Yadav
- Department
of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Judith L. Winogrodzki
- Department
of Microbiology, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Keith A. Stubbs
- School
of Chemistry and Biochemistry, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Brian L. Mark
- Department
of Microbiology, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - David J. Vocadlo
- Department
of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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Efficient and Regioselective Synthesis of β-GalNAc/GlcNAc-Lactose by a Bifunctional Transglycosylating β-N-Acetylhexosaminidase from Bifidobacterium bifidum. Appl Environ Microbiol 2016; 82:5642-52. [PMID: 27422836 DOI: 10.1128/aem.01325-16] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 06/29/2016] [Indexed: 01/08/2023] Open
Abstract
UNLABELLED β-N-Acetylhexosaminidases have attracted interest particularly for oligosaccharide synthesis, but their use remains limited by the rarity of enzyme sources , low efficiency, and relaxed regioselectivity of transglycosylation. In this work, genes of 13 β-N-acetylhexosaminidases, including 5 from Bacteroides fragilis ATCC 25285, 5 from Clostridium perfringens ATCC 13124, and 3 from Bifidobacterium bifidum JCM 1254, were cloned and heterogeneously expressed in Escherichia coli The resulting recombinant enzymes were purified and screened for transglycosylation activity. A β-N-acetylhexosaminidase named BbhI, which belongs to glycoside hydrolase family 20 and was obtained from B. bifidum JCM 1254, possesses the bifunctional property of efficiently transferring both GalNAc and GlcNAc residues through β1-3 linkage to the Gal residue of lactose. The effects of initial substrate concentration, pH, temperature, and reaction time on transglycosylation activities of BbhI were studied in detail. With the use of 10 mM pNP-β-GalNAc or 20 mM pNP-β-GlcNAc as the donor and 400 mM lactose as the acceptor in phosphate buffer (pH 5.8), BbhI synthesized GalNAcβ1-3Galβ1-4Glc and GlcNAcβ1-3Galβ1-4Glc at maximal yields of 55.4% at 45°C and 4 h and 44.9% at 55°C and 1.5 h, respectively. The model docking of BbhI with lactose showed the possible molecular basis of strict regioselectivity of β1-3 linkage in β-N-acetylhexosaminyl lactose synthesis. IMPORTANCE Oligosaccharides play a crucial role in many biological events and therefore are promising potential therapeutic agents. However, their use is limited because large-scale production of oligosaccharides is difficult. The chemical synthesis requires multiple protecting group manipulations to control the regio- and stereoselectivity of glycosidic bonds. In comparison, enzymatic synthesis can produce oligosaccharides in one step by using glycosyltransferases and glycosidases. Given the lower price of their glycosyl donor and their broader acceptor specificity, glycosidases are more advantageous than glycosyltransferases for large-scale synthesis. β-N-Acetylhexosaminidases have attracted interest particularly for β-N-acetylhexosaminyl oligosaccharide synthesis, but their application is affected by having few enzyme sources, low efficiency, and relaxed regioselectivity of transglycosylation. In this work, we describe a microbial β-N-acetylhexosaminidase that exhibited strong transglycosylation activity and strict regioselectivity for β-N-acetylhexosaminyl lactose synthesis and thus provides a powerful synthetic tool to obtain biologically important GalNAcβ1-3Lac and GlcNAcβ1-3Lac.
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Domínguez-Gil T, Molina R, Alcorlo M, Hermoso JA. Renew or die: The molecular mechanisms of peptidoglycan recycling and antibiotic resistance in Gram-negative pathogens. Drug Resist Updat 2016; 28:91-104. [PMID: 27620957 DOI: 10.1016/j.drup.2016.07.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Antimicrobial resistance is one of the most serious health threats. Cell-wall remodeling processes are tightly regulated to warrant bacterial survival and in some cases are directly linked to antibiotic resistance. Remodeling produces cell-wall fragments that are recycled but can also act as messengers for bacterial communication, as effector molecules in immune response and as signaling molecules triggering antibiotic resistance. This review is intended to provide state-of-the-art information about the molecular mechanisms governing this process and gather structural information of the different macromolecular machineries involved in peptidoglycan recycling in Gram-negative bacteria. The growing body of literature on the 3D structures of the corresponding macromolecules reveals an extraordinary complexity. Considering the increasing incidence and widespread emergence of Gram-negative multidrug-resistant pathogens in clinics, structural information on the main actors of the recycling process paves the way for designing novel antibiotics disrupting cellular communication in the recycling-resistance pathway.
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Affiliation(s)
- Teresa Domínguez-Gil
- Department of Crystallography and Structural Biology, Inst. Química-Física "Rocasolano", CSIC, Serrano 119, 28006 Madrid, Spain
| | - Rafael Molina
- Department of Crystallography and Structural Biology, Inst. Química-Física "Rocasolano", CSIC, Serrano 119, 28006 Madrid, Spain
| | - Martín Alcorlo
- Department of Crystallography and Structural Biology, Inst. Química-Física "Rocasolano", CSIC, Serrano 119, 28006 Madrid, Spain
| | - Juan A Hermoso
- Department of Crystallography and Structural Biology, Inst. Química-Física "Rocasolano", CSIC, Serrano 119, 28006 Madrid, Spain.
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Broughton CE, Van Den Berg HA, Wemyss AM, Roper DI, Rodger A. Beyond the Discovery Void: New targets for antibacterial compounds. Sci Prog 2016; 99:153-182. [PMID: 28742471 PMCID: PMC10365418 DOI: 10.3184/003685016x14616130512308] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Antibiotics save many lives, but their efficacy is under threat: overprescription, population growth, and global travel all contribute to the rapid origination and spread of resistant strains. Exacerbating this threat is the fact that no new major classes of antibiotics have been discovered in the last 30 years: this is the "discovery void." We discuss the traditional molecular targets of antibiotics as well as putative novel targets.
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Affiliation(s)
| | | | - Alan M. Wemyss
- Molecular Organisation and Assembly in Cells Doctoral Training Centre
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Pseudomonas aeruginosa: targeting cell-wall metabolism for new antibacterial discovery and development. Future Med Chem 2016; 8:975-92. [PMID: 27228070 DOI: 10.4155/fmc-2016-0017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Pseudomonas aeruginosa is a leading cause of hospital-acquired infections and is resistant to most antibiotics. With therapeutic options against P. aeruginosa dwindling, and the lack of new antibiotics in advanced developmental stages, strategies for preserving the effectiveness of current antibiotics are urgently required. β-Lactam antibiotics are important agents for treating P. aeruginosa infections, thus, adjuvants that potentiate the activity of these compounds are desirable for extending their lifespan while new antibiotics - or antibiotic classes - are discovered and developed. In this review, we discuss recent research that has identified exploitable targets of cell-wall metabolism for the design and development of compounds that hinder resistance and potentiate the activity of antipseudomonal β-lactams.
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Abstract
Bacterial-bacterial interactions play a critical role in promoting biofilm formation. Here we show that NagZ, a protein associated with peptidoglycan recycling, has moonlighting activity that allows it to modulate biofilm accumulation by Neisseria gonorrhoeae. We characterize the biochemical properties of NagZ and demonstrate its ability to function as a dispersing agent for biofilms formed on abiotic surfaces. We extend these observations to cell culture and tissue explant models and show that in nagZ mutants, the biofilms formed in cell culture and on human tissues contain significantly more biomass than those formed by a wild-type strain. Our results demonstrate that an enzyme thought to be restricted to peptidoglycan recycling is able to disperse preformed biofilms.
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Kappel L, Gaderer R, Flipphi M, Seidl-Seiboth V. The N-acetylglucosamine catabolic gene cluster in Trichoderma reesei is controlled by the Ndt80-like transcription factor RON1. Mol Microbiol 2016; 99:640-57. [PMID: 26481444 PMCID: PMC4950302 DOI: 10.1111/mmi.13256] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/19/2015] [Indexed: 11/28/2022]
Abstract
Chitin is an important structural constituent of fungal cell walls composed of N-acetylglucosamine (GlcNAc) monosaccharides, but catabolism of GlcNAc has not been studied in filamentous fungi so far. In the yeast Candida albicans, the genes encoding the three enzymes responsible for stepwise conversion of GlcNAc to fructose-6-phosphate are clustered. In this work, we analysed GlcNAc catabolism in ascomycete filamentous fungi and found that the respective genes are also clustered in these fungi. In contrast to C. albicans, the cluster often contains a gene for an Ndt80-like transcription factor, which we named RON1 (regulator of N-acetylglucosamine catabolism 1). Further, a gene for a glycoside hydrolase 3 protein related to bacterial N-acetylglucosaminidases can be found in the GlcNAc gene cluster in filamentous fungi. Functional analysis in Trichoderma reesei showed that the transcription factor RON1 is a key activator of the GlcNAc gene cluster and essential for GlcNAc catabolism. Furthermore, we present an evolutionary analysis of Ndt80-like proteins in Ascomycota. All GlcNAc cluster genes, as well as the GlcNAc transporter gene ngt1, and an additional transcriptional regulator gene, csp2, encoding the homolog of Neurospora crassa CSP2/GRHL, were functionally characterised by gene expression analysis and phenotypic characterisation of knockout strains in T. reesei.
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Affiliation(s)
- Lisa Kappel
- Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Vienna, Austria
| | - Romana Gaderer
- Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Vienna, Austria
| | - Michel Flipphi
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - Verena Seidl-Seiboth
- Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Vienna, Austria
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50
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Su H, Sheng X, Liu Y. Insights into the catalytic mechanism of N-acetylglucosaminidase glycoside hydrolase from Bacillus subtilis: a QM/MM study. Org Biomol Chem 2016; 14:3432-42. [DOI: 10.1039/c6ob00320f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
QM/MM calculations on NagZs fromBacillus subtilisfurther confirm NagZs to be glycoside phosphorylases rather than glycoside hydrolases.
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Affiliation(s)
- Hao Su
- Key Laboratory of Colloid and Interface Chemistry
- Ministry of Education
- School of Chemistry and Chemical Engineering
- Shandong University
- Jinan
| | - Xiang Sheng
- Key Laboratory of Colloid and Interface Chemistry
- Ministry of Education
- School of Chemistry and Chemical Engineering
- Shandong University
- Jinan
| | - Yongjun Liu
- Key Laboratory of Colloid and Interface Chemistry
- Ministry of Education
- School of Chemistry and Chemical Engineering
- Shandong University
- Jinan
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