1
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Perez AJ, Lamanna MM, Bruce KE, Touraev MA, Page JE, Shaw SL, Tsui HCT, Winkler ME. Elongasome core proteins and class A PBP1a display zonal, processive movement at the midcell of Streptococcus pneumoniae. Proc Natl Acad Sci U S A 2024; 121:e2401831121. [PMID: 38875147 PMCID: PMC11194595 DOI: 10.1073/pnas.2401831121] [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: 02/07/2024] [Accepted: 05/02/2024] [Indexed: 06/16/2024] Open
Abstract
Ovoid-shaped bacteria, such as Streptococcus pneumoniae (pneumococcus), have two spatially separated peptidoglycan (PG) synthase nanomachines that locate zonally to the midcell of dividing cells. The septal PG synthase bPBP2x:FtsW closes the septum of dividing pneumococcal cells, whereas the elongasome located on the outer edge of the septal annulus synthesizes peripheral PG outward. We showed previously by sm-TIRFm that the septal PG synthase moves circumferentially at midcell, driven by PG synthesis and not by FtsZ treadmilling. The pneumococcal elongasome consists of the PG synthase bPBP2b:RodA, regulators MreC, MreD, and RodZ, but not MreB, and genetically associated proteins Class A aPBP1a and muramidase MpgA. Given its zonal location separate from FtsZ, it was of considerable interest to determine the dynamics of proteins in the pneumococcal elongasome. We found that bPBP2b, RodA, and MreC move circumferentially with the same velocities and durations at midcell, driven by PG synthesis. However, outside of the midcell zone, the majority of these elongasome proteins move diffusively over the entire surface of cells. Depletion of MreC resulted in loss of circumferential movement of bPBP2b, and bPBP2b and RodA require each other for localization and circumferential movement. Notably, a fraction of aPBP1a molecules also moved circumferentially at midcell with velocities similar to those of components of the core elongasome, but for shorter durations. Other aPBP1a molecules were static at midcell or diffusing over cell bodies. Last, MpgA displayed nonprocessive, subdiffusive motion that was largely confined to the midcell region and less frequently detected over the cell body.
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Affiliation(s)
- Amilcar J. Perez
- Department of Biology, Indiana University Bloomington, Bloomington, IN47405
| | - Melissa M. Lamanna
- Department of Biology, Indiana University Bloomington, Bloomington, IN47405
| | - Kevin E. Bruce
- Department of Biology, Indiana University Bloomington, Bloomington, IN47405
| | - Marc A. Touraev
- Department of Biology, Indiana University Bloomington, Bloomington, IN47405
| | - Julia E. Page
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA02115
| | - Sidney L. Shaw
- Department of Biology, Indiana University Bloomington, Bloomington, IN47405
| | | | - Malcolm E. Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, IN47405
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2
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Tandukar S, Kwon E, Kim DY. Structural analysis of the peptidoglycan DL-endopeptidase CwlO complexed with its inhibitory protein IseA. FEBS J 2024. [PMID: 38840475 DOI: 10.1111/febs.17197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 03/08/2024] [Accepted: 05/28/2024] [Indexed: 06/07/2024]
Abstract
Peptidoglycan DL-endopeptidases locally cleave the peptide stem of peptidoglycan in the bacterial cell wall. This process facilitates bacterial growth and division by loosening the rigid peptidoglycan layer. IseA binds to the active site of multiple DL-endopeptidases and inhibits excessive peptidoglycan degradation that leads to cell lysis. To better understand how IseA inhibits DL-endopeptidase activity, we determined the crystal structure of the peptidoglycan DL-endopeptidase CwlO/IseA complex and compared it with that of the peptidoglycan DL-endopeptidase LytE/IseA complex. Structural analyses showed significant differences between the hydrophobic pocket-binding residues of the DL-endopeptidases (F361 of CwlO and W237 of LytE). Additionally, binding assays showed that the F361 mutation of CwlO to the bulkier hydrophobic residue, tryptophan, increased its binding affinity for IseA, whereas mutation to alanine reduced the affinity. These analyses revealed that the hydrophobic pocket-binding residue of DL-endopeptidases determines IseA-binding affinity and is required for substrate-mimetic inhibition by IseA.
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Affiliation(s)
| | - Eunju Kwon
- Division of Life Science, Gyeongsang National University, Jinju, Korea
- Research Institute of Molecular Alchemy, Gyeongsang National University, Jinju, Korea
| | - Dong Young Kim
- College of Pharmacy, Yeungnam University, Gyeongsan, Korea
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3
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Perez AJ, Lamanna MM, Bruce KE, Touraev MA, Page JE, Shaw SL, Tsui HCT, Winkler ME. Elongasome core proteins and class A PBP1a display zonal, processive movement at the midcell of Streptococcus pneumoniae. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.10.575112. [PMID: 38328058 PMCID: PMC10849506 DOI: 10.1101/2024.01.10.575112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Ovoid-shaped bacteria, such as Streptococcus pneumoniae (pneumococcus), have two spatially separated peptidoglycan (PG) synthase nanomachines that locate zonally to the midcell of dividing cells. The septal PG synthase bPBP2x:FtsW closes the septum of dividing pneumococcal cells, whereas the elongasome located on the outer edge of the septal annulus synthesizes peripheral PG outward. We showed previously by sm-TIRFm that the septal PG synthase moves circumferentially at midcell, driven by PG synthesis and not by FtsZ treadmilling. The pneumococcal elongasome consists of the PG synthase bPBP2b:RodA, regulators MreC, MreD, and RodZ, but not MreB, and genetically associated proteins Class A aPBP1a and muramidase MpgA. Given its zonal location separate from FtsZ, it was of considerable interest to determine the dynamics of proteins in the pneumococcal elongasome. We found that bPBP2b, RodA, and MreC move circumferentially with the same velocities and durations at midcell, driven by PG synthesis. However, outside of the midcell zone, the majority of these elongasome proteins move diffusively over the entire surface of cells. Depletion of MreC resulted in loss of circumferential movement of bPBP2b, and bPBP2b and RodA require each other for localization and circumferential movement. Notably, a fraction of aPBP1a molecules also moved circumferentially at midcell with velocities similar to those of components of the core elongasome, but for shorter durations. Other aPBP1a molecules were static at midcell or diffusing over cell bodies. Last, MpgA displayed non-processive, subdiffusive motion that was largely confined to the midcell region and less frequently detected over the cell body.
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4
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Guo T, Sperber AM, Krieger IV, Duan Y, Chemelewski VR, Sacchettini JC, Herman JK. Bacillus subtilis YisK possesses oxaloacetate decarboxylase activity and exhibits Mbl-dependent localization. J Bacteriol 2024; 206:e0020223. [PMID: 38047707 PMCID: PMC10810218 DOI: 10.1128/jb.00202-23] [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: 06/28/2023] [Accepted: 11/10/2023] [Indexed: 12/05/2023] Open
Abstract
YisK is an uncharacterized protein in Bacillus subtilis previously shown to interact genetically with the elongasome protein Mbl. YisK overexpression leads to cell widening and lysis, phenotypes that are dependent on mbl and suppressed by mbl mutations. In the present work, we characterize YisK's localization, structure, and enzymatic activity. We show that YisK localizes as puncta that depend on Mbl. YisK belongs to the fumarylacetoacetate hydrolase (FAH) superfamily, and crystal structures revealed close structural similarity to two oxaloacetate (OAA) decarboxylases: human mitochondrial FAHD1 and Corynebacterium glutamicum Cg1458. We demonstrate that YisK can also catalyze the decarboxylation of OAA (K m = 134 µM, K cat = 31 min-1). A catalytic dead variant (YisK E148A, E150A) retains wild-type localization and still widens cells following overexpression, indicating these activities are not dependent on YisK catalysis. Conversely, a non-localizing variant (YisK E30A) retains wild-type enzymatic activity in vitro but localizes diffusely and no longer widens cells following overexpression. Together, these results suggest that YisK may be subject to spatial regulation that depends on the cell envelope synthesis machinery. IMPORTANCE The elongasome is a multiprotein complex that guides lengthwise growth in some bacteria. We previously showed that, in B. subtilis, overexpression of an uncharacterized putative enzyme (YisK) perturbed function of the actin-like elongasome protein Mbl. Here, we show that YisK exhibits Mbl-dependent localization. Through biochemical and structural characterization, we demonstrate that, like its mitochondrial homolog FAHD1, YisK can catalyze the decarboxylation of the oxaloacetate to pyruvate and CO2. YisK is the first example of an enzyme implicated in central carbon metabolism with subcellular localization that depends on Mbl.
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Affiliation(s)
- Tingfeng Guo
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
| | - Anthony M. Sperber
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
| | - Inna V. Krieger
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
| | - Yi Duan
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
| | - Veronica R. Chemelewski
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
| | - James C. Sacchettini
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
- Department of Chemistry, Texas A&M University, College Station, Texas, USA
| | - Jennifer K. Herman
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
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5
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Kitahara Y, van Teeffelen S. Bacterial growth - from physical principles to autolysins. Curr Opin Microbiol 2023; 74:102326. [PMID: 37279609 DOI: 10.1016/j.mib.2023.102326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 04/11/2023] [Accepted: 04/13/2023] [Indexed: 06/08/2023]
Abstract
For bacteria to increase in size, they need to enzymatically expand their cell envelopes, and more concretely their peptidoglycan cell wall. A major task of growth is to increase intracellular space for the accumulation of macromolecules, notably proteins, RNA, and DNA. Here, we review recent progress in our understanding of how cells coordinate envelope growth with biomass growth, focusing on elongation of rod-like bacteria. We first describe the recent discovery that surface area, but not cell volume, increases in proportion to mass growth. We then discuss how this relation could possibly be implemented mechanistically, reviewing the role of envelope insertion for envelope growth. Since cell-wall expansion requires the well-controlled activity of autolysins, we finally review recent progress in our understanding of autolysin regulation.
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Affiliation(s)
- Yuki Kitahara
- Département de Microbiologie, Infectiologie, et Immunologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Sven van Teeffelen
- Département de Microbiologie, Infectiologie, et Immunologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada.
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6
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Kawai Y, Errington J. Dissecting the roles of peptidoglycan synthetic and autolytic activities in the walled to L-form bacterial transition. Front Microbiol 2023; 14:1204979. [PMID: 37333659 PMCID: PMC10272550 DOI: 10.3389/fmicb.2023.1204979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 05/10/2023] [Indexed: 06/20/2023] Open
Abstract
Bacterial cells are surrounded by a peptidoglycan (PG) wall, which is a crucial target for antibiotics. It is well known that treatment with cell wall-active antibiotics occasionally converts bacteria to a non-walled "L-form" state that requires the loss of cell wall integrity. L-forms may have an important role in antibiotic resistance and recurrent infection. Recent work has revealed that inhibition of de novo PG precursor synthesis efficiently induces the L-form conversion in a wide range of bacteria, but the molecular mechanisms remain poorly understood. Growth of walled bacteria requires the orderly expansion of the PG layer, which involves the concerted action not just of synthases but also degradative enzymes called autolysins. Most rod-shaped bacteria have two complementary systems for PG insertion, the Rod and aPBP systems. Bacillus subtilis has two major autolysins, called LytE and CwlO, which are thought to have partially redundant functions. We have dissected the functions of autolysins, relative to the Rod and aPBP systems, during the switch to L-form state. Our results suggest that when de novo PG precursor synthesis is inhibited, residual PG synthesis occurs specifically via the aPBP pathway, and that this is required for continued autolytic activity by LytE/CwlO, resulting in cell bulging and efficient L-form emergence. The failure of L-form generation in cells lacking aPBPs was rescued by enhancing the Rod system and in this case, emergence specifically required LytE but was not associated with cell bulging. Our results suggest that two distinct pathways of L-form emergence exist depending on whether PG synthesis is being supported by the aPBP or RodA PG synthases. This work provides new insights into mechanisms of L-form generation, and specialisation in the roles of essential autolysins in relation to the recently recognised dual PG synthetic systems of bacteria.
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7
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Griffin ME, Klupt S, Espinosa J, Hang HC. Peptidoglycan NlpC/P60 peptidases in bacterial physiology and host interactions. Cell Chem Biol 2023; 30:436-456. [PMID: 36417916 PMCID: PMC10192474 DOI: 10.1016/j.chembiol.2022.11.001] [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: 05/18/2022] [Revised: 09/15/2022] [Accepted: 10/31/2022] [Indexed: 11/23/2022]
Abstract
The bacterial cell wall is composed of a highly crosslinked matrix of glycopeptide polymers known as peptidoglycan that dictates bacterial cell morphology and protects against environmental stresses. Regulation of peptidoglycan turnover is therefore crucial for bacterial survival and growth and is mediated by key protein complexes and enzyme families. Here, we review the prevalence, structure, and activity of NlpC/P60 peptidases, a family of peptidoglycan hydrolases that are crucial for cell wall turnover and division as well as interactions with antibiotics and different hosts. Understanding the molecular functions of NlpC/P60 peptidases should provide important insight into bacterial physiology, their interactions with different kingdoms of life, and the development of new therapeutic approaches.
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Affiliation(s)
- Matthew E Griffin
- Department of Immunology and Microbiology, Scripps Research, La Jolla, CA 92037, USA
| | - Steven Klupt
- Department of Immunology and Microbiology, Scripps Research, La Jolla, CA 92037, USA
| | - Juliel Espinosa
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY 10065, USA
| | - Howard C Hang
- Department of Immunology and Microbiology, Scripps Research, La Jolla, CA 92037, USA; Department of Chemistry, Scripps Research, La Jolla, CA 92037, USA.
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8
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Brogan AP, Rudner DZ. Regulation of peptidoglycan hydrolases: localization, abundance, and activity. Curr Opin Microbiol 2023; 72:102279. [PMID: 36812681 PMCID: PMC10031507 DOI: 10.1016/j.mib.2023.102279] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/17/2023] [Accepted: 01/18/2023] [Indexed: 02/22/2023]
Abstract
Most bacteria are surrounded by a cell wall composed of peptidoglycan (PG) that specifies shape and protects the cell from osmotic rupture. Growth, division, and morphogenesis are intimately linked to the synthesis of this exoskeleton but also its hydrolysis. The enzymes that cleave the PG meshwork require careful control to prevent aberrant hydrolysis and loss of envelope integrity. Bacteria employ diverse mechanisms to control the activity, localization, and abundance of these potentially autolytic enzymes. Here, we discuss four examples of how cells integrate these control mechanisms to finely tune cell wall hydrolysis. We highlight recent advances and exciting avenues for future investigation.
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Affiliation(s)
- Anna P Brogan
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - David Z Rudner
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA.
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9
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Abstract
Gram-positive bacterial cells are protected from the environment by a cell envelope that is comprised of a thick layer of peptidoglycan that maintains cell shape and teichoic acid polymers whose biological function remains unclear. In Bacillus subtilis, the loss of all class A penicillin-binding proteins (aPBPs), which function in peptidoglycan synthesis, is conditionally lethal. Here, we show that this lethality is associated with an alteration of lipoteichoic acids (LTAs) and the accumulation of the major autolysin LytE in the cell wall. Our analysis provides further evidence that the length and abundance of LTAs act to regulate the cellular level and activity of autolytic enzymes, specifically LytE. Importantly, we identify a novel function for the aminoacyl-phosphatidylglycerol synthase MprF in the modulation of LTA biosynthesis in both B. subtilis and Staphylococcus aureus. This finding has implications for our understanding of antimicrobial resistance (particularly to daptomycin) in clinically relevant bacteria and the involvement of MprF in the virulence of pathogens such as methicillin-resistant S. aureus (MRSA). IMPORTANCE In Gram-positive bacteria such as Bacillus subtilis and Staphylococcus aureus, the cell envelope is a structure that protects the cells from the environment but is also dynamic in that it must be modified in a controlled way to allow cell growth. In this study, we show that lipoteichoic acids (LTAs), which are anionic polymers attached to the membrane, have a direct role in modulating the cellular abundance of cell wall-degrading enzymes. We also find that the apparent length of the LTA is modulated by the activity of the enzyme MprF, previously implicated in modifications of the cell membrane leading to resistance to antimicrobial peptides. These findings are important contributions to our understanding of how bacteria balance cell wall synthesis and degradation to permit controlled growth and division. These results also have implications for the interpretation of antibiotic resistance, particularly for the clinical treatment of MRSA infections.
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10
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Schulz LM, Rothe P, Halbedel S, Gründling A, Rismondo J. Imbalance of peptidoglycan biosynthesis alters the cell surface charge of Listeria monocytogenes. Cell Surf 2022; 8:100085. [PMID: 36304571 PMCID: PMC9593813 DOI: 10.1016/j.tcsw.2022.100085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 10/19/2022] [Accepted: 10/19/2022] [Indexed: 02/09/2023] Open
Abstract
The bacterial cell wall is composed of a thick layer of peptidoglycan and cell wall polymers, which are either embedded in the membrane or linked to the peptidoglycan backbone and referred to as lipoteichoic acid (LTA) and wall teichoic acid (WTA), respectively. Modifications of the peptidoglycan or WTA backbone can alter the susceptibility of the bacterial cell towards cationic antimicrobials and lysozyme. The human pathogen Listeria monocytogenes is intrinsically resistant towards lysozyme, mainly due to deacetylation and O-acetylation of the peptidoglycan backbone via PgdA and OatA. Recent studies identified additional factors, which contribute to the lysozyme resistance of this pathogen. One of these is the predicted ABC transporter, EslABC. An eslB mutant is hyper-sensitive towards lysozyme, likely due to the production of thinner and less O-acetylated peptidoglycan. Using a suppressor screen, we show here that suppression of eslB phenotypes could be achieved by enhancing peptidoglycan biosynthesis, reducing peptidoglycan hydrolysis or alterations in WTA biosynthesis and modification. The lack of EslB also leads to a higher negative surface charge, which likely stimulates the activity of peptidoglycan hydrolases and lysozyme. Based on our results, we hypothesize that the portion of cell surface exposed WTA is increased in the eslB mutant due to the thinner peptidoglycan layer and that latter one could be caused by an impairment in UDP-N-acetylglucosamine (UDP-GlcNAc) production or distribution.
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Affiliation(s)
- Lisa Maria Schulz
- Department of General Microbiology, Institute of Microbiology and Genetics, GZMB, Georg-August University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
| | - Patricia Rothe
- FG11, Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, Burgstraße 37, 38855 Wernigerode, Germany
| | - Sven Halbedel
- FG11, Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, Burgstraße 37, 38855 Wernigerode, Germany
- Institute for Medical Microbiology and Hospital Hygiene, Otto von Guericke University Magdeburg, Leipziger Straße 44, 39120 Magdeburg, Germany
| | - Angelika Gründling
- Section of Molecular Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Jeanine Rismondo
- Department of General Microbiology, Institute of Microbiology and Genetics, GZMB, Georg-August University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
- Section of Molecular Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
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11
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Zhang Z, He P, Cai D, Chen S. Genetic and metabolic engineering for poly-γ-glutamic acid production: current progress, challenges, and prospects. World J Microbiol Biotechnol 2022; 38:208. [DOI: 10.1007/s11274-022-03390-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 08/13/2022] [Indexed: 11/29/2022]
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12
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Brunet YR, Habib C, Brogan AP, Artzi L, Rudner DZ. Intrinsically disordered protein regions are required for cell wall homeostasis in Bacillus subtilis. Genes Dev 2022; 36:970-984. [PMID: 36265902 PMCID: PMC9732909 DOI: 10.1101/gad.349895.122] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 10/03/2022] [Indexed: 01/07/2023]
Abstract
Intrinsically disordered protein regions (IDRs) have been implicated in diverse nuclear and cytoplasmic functions in eukaryotes, but their roles in bacteria are less clear. Here, we report that extracytoplasmic IDRs in Bacillus subtilis are required for cell wall homeostasis. The B. subtilis σI transcription factor is activated in response to envelope stress through regulated intramembrane proteolysis (RIP) of its membrane-anchored anti-σ factor, RsgI. Unlike canonical RIP pathways, we show that ectodomain (site-1) cleavage of RsgI is constitutive, but the two cleavage products remain stably associated, preventing intramembrane (site-2) proteolysis. The regulated step in this pathway is their dissociation, which is triggered by impaired cell wall synthesis and requires RsgI's extracytoplasmic IDR. Intriguingly, the major peptidoglycan polymerase PBP1 also contains an extracytoplasmic IDR, and we show that this region is important for its function. Disparate IDRs can replace the native IDRs on both RsgI and PBP1, arguing that these unstructured regions function similarly. Our data support a model in which the RsgI-σI signaling system and PBP1 represent complementary pathways to repair gaps in the PG meshwork. The IDR on RsgI senses these gaps and activates σI, while the IDR on PBP1 directs the synthase to these sites to fortify them.
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Affiliation(s)
- Yannick R. Brunet
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Cameron Habib
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Anna P. Brogan
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Lior Artzi
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - David Z. Rudner
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115, USA
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13
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Wang J, Yu Q, Peng Q, Slamti L, Zhang R, Hou S, Lereclus D, Song F. Deletion of the novel gene mother cell lysis X results in Cry1Ac encapsulation in the Bacillus thuringiensis HD73. Front Microbiol 2022; 13:951830. [PMID: 36016772 PMCID: PMC9397120 DOI: 10.3389/fmicb.2022.951830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 07/14/2022] [Indexed: 11/13/2022] Open
Abstract
The novel protein MclX (mother cell lysis X) in Bacillus thuringiensis subsp. kurstaki strain HD73 (B. thuringiensis HD73) was characterized in this work. MclX has no known domain and its gene deletion in HD73 resulted in Cry1Ac encapsulation in the mother cell and did not influence Cry1Ac protein production or insecticidal activity. In vitro cell wall hydrolysis experiments showed that MclX cannot hydrolyze the cell wall. In mclX deletion mutants, the expression of cwlC (which encodes a key cell wall hydrolase) was significantly decreased, as shown by the β-galactosidase activity assay. MclX cannot directly bind to the cwlC promoter, based on the electrophoretic mobility shift assay (EMSA). The cwlC was reported to be regulated by σK and GerE. However, the transcriptional activities of sigK and gerE showed no difference between HD73 and the mclX deletion mutant. It is indicated that MclX influenced cwlC expression independently of σK or GerE, through a new pathway to regulate cwlC expression. mclX deletion could be a new approach for insecticidal protein encapsulation in Bacillus thuringiensis.
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Affiliation(s)
- Jiaojiao Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Qingyue Yu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Qi Peng
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Leyla Slamti
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Ruibin Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Shuo Hou
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Didier Lereclus
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Fuping Song
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- *Correspondence: Fuping Song,
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14
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Kitahara Y, Oldewurtel ER, Wilson S, Sun Y, Altabe S, de Mendoza D, Garner EC, van Teeffelen S. The role of cell-envelope synthesis for envelope growth and cytoplasmic density in Bacillus subtilis. PNAS NEXUS 2022; 1:pgac134. [PMID: 36082236 PMCID: PMC9437589 DOI: 10.1093/pnasnexus/pgac134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 07/21/2022] [Indexed: 01/29/2023]
Abstract
All cells must increase their volumes in response to biomass growth to maintain intracellular mass density within physiologically permissive bounds. Here, we investigate the regulation of volume growth in the Gram-positive bacterium Bacillus subtilis. To increase volume, bacteria enzymatically expand their cell envelopes and insert new envelope material. First, we demonstrate that cell-volume growth is determined indirectly, by expanding their envelopes in proportion to mass growth, similarly to the Gram-negative Escherichia coli, despite their fundamentally different envelope structures. Next, we studied, which pathways might be responsible for robust surface-to-mass coupling: We found that both peptidoglycan synthesis and membrane synthesis are required for proper surface-to-mass coupling. However, surprisingly, neither pathway is solely rate-limiting, contrary to wide-spread belief, since envelope growth continues at a reduced rate upon complete inhibition of either process. To arrest cell-envelope growth completely, the simultaneous inhibition of both envelope-synthesis processes is required. Thus, we suggest that multiple envelope-synthesis pathways collectively confer an important aspect of volume regulation, the coordination between surface growth, and biomass growth.
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Affiliation(s)
- Yuki Kitahara
- Département de Microbiologie, Infectiologie, et Immunologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada,Université de Paris, Paris, France,Microbial Morphogenesis and Growth Lab, Institut Pasteur, Paris, France
| | - Enno R Oldewurtel
- Microbial Morphogenesis and Growth Lab, Institut Pasteur, Paris, France
| | - Sean Wilson
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, USA,Center for Systems Biology, Harvard University, Cambridge, MA, USA
| | - Yingjie Sun
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, USA,Center for Systems Biology, Harvard University, Cambridge, MA, USA
| | - Silvia Altabe
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Conicet- and Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Diego de Mendoza
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Conicet- and Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Ethan C Garner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, USA,Center for Systems Biology, Harvard University, Cambridge, MA, USA
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15
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Hammond LR, Sacco MD, Khan SJ, Spanoudis C, Hough-Neidig A, Chen Y, Eswara PJ. GpsB Coordinates Cell Division and Cell Surface Decoration by Wall Teichoic Acids in Staphylococcus aureus. Microbiol Spectr 2022; 10:e0141322. [PMID: 35647874 PMCID: PMC9241681 DOI: 10.1128/spectrum.01413-22] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 05/12/2022] [Indexed: 11/20/2022] Open
Abstract
Bacterial cell division is a complex and highly regulated process requiring the coordination of many different proteins. Despite substantial work in model organisms, our understanding of the systems regulating cell division in noncanonical organisms, including critical human pathogens, is far from complete. One such organism is Staphylococcus aureus, a spherical bacterium that lacks known cell division regulatory proteins. Recent studies on GpsB, a protein conserved within the Firmicutes phylum, have provided insight into cell division regulation in S. aureus and other related organisms. It has been revealed that GpsB coordinates cell division and cell wall synthesis in multiple species. In S. aureus, we have previously shown that GpsB directly regulates FtsZ polymerization. In this study, using Bacillus subtilis as a tool, we isolated spontaneous suppressors that abrogate the lethality of S. aureus GpsB overproduction in B. subtilis. Through characterization, we identified several residues important for the function of GpsB. Furthermore, we discovered an additional role for GpsB in wall teichoic acid (WTA) biosynthesis in S. aureus. Specifically, we show that GpsB directly interacts with the WTA export protein TarG. We also identified a region in GpsB that is crucial for this interaction. Analysis of TarG localization in S. aureus suggests that WTA machinery is part of the divisome complex. Taken together, this research illustrates how GpsB performs an essential function in S. aureus by directly linking the tightly regulated cell cycle processes of cell division and WTA-mediated cell surface decoration. IMPORTANCE Cytokinesis in bacteria involves an intricate orchestration of several key cell division proteins and other factors involved in building a robust cell envelope. Presence of teichoic acids is a signature characteristic of the Gram-positive cell wall. By characterizing the role of Staphylococcus aureus GpsB, an essential cell division protein in this organism, we have uncovered an additional role for GpsB in wall teichoic acid (WTA) biosynthesis. We show that GpsB directly interacts with TarG of the WTA export complex. We also show that this function of GpsB may be conserved in other GpsB homologs as GpsB and the WTA exporter complex follow similar localization patterns. It has been suggested that WTA acts as a molecular signal to control the activity of autolytic enzymes, especially during the separation of conjoined daughter cells. Thus, our results reveal that GpsB, in addition to playing a role in cell division, may also help coordinate WTA biogenesis.
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Affiliation(s)
- Lauren R. Hammond
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, Florida, USA
| | - Michael D. Sacco
- Department of Molecular Medicine, University of South Florida, Tampa, Florida, USA
| | - Sebastian J. Khan
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, Florida, USA
| | - Catherine Spanoudis
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, Florida, USA
| | - Abigail Hough-Neidig
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, Florida, USA
| | - Yu Chen
- Department of Molecular Medicine, University of South Florida, Tampa, Florida, USA
| | - Prahathees J. Eswara
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, Florida, USA
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16
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Xu Y, Yang L, Wang H, Wei X, Shi Y, Liang D, Cao M, He N. Putative functions of EpsK in teichuronic acid synthesis and phosphate starvation in Bacillus licheniformis. Synth Syst Biotechnol 2022; 7:815-823. [PMID: 35475252 PMCID: PMC9018123 DOI: 10.1016/j.synbio.2022.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/31/2022] [Accepted: 04/01/2022] [Indexed: 11/28/2022] Open
Abstract
Extracellular polymeric substances (EPSs) are extracellular macromolecules in bacteria, which function in cell growth and show potential for mechanism study and biosynthesis application. However, the biosynthesis mechanism of EPS is still not clear. We herein chose Bacillus licheniformis CGMCC 2876 as a target strain to investigate the EPS biosynthesis. epsK, a member of eps cluster, the predicted polysaccharide synthesis cluster, was overexpressed and showed that the overexpression of epsK led to a 26.54% decrease in the production of EPS and resulted in slenderer cell shape. Transcriptome analysis combined with protein-protein interactions analysis and protein modeling revealed that epsK was likely responsible for the synthesis of teichuronic acid, a substitute cell wall component of teichoic acid when the strain was suffering phosphate limitation. Further cell cultivation showed that either phosphate limitation or the overexpression of teichuronic acid synthesis genes, tuaB and tuaE could similarly lead to EPS reduction. The enhanced production of teichuronic acid induced by epsK overexpression triggered the endogenous phosphate starvation, resulting in the decreased EPS synthesis and biomass, and the enhanced bacterial chemotaxis. This study presents an insight into the mechanism of EPS synthesis and offers the potential in controllable synthesis of target products.
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Affiliation(s)
- Yiyuan Xu
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, PR China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China
| | - Lijie Yang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, PR China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China
| | - Haiyan Wang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, PR China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China
| | - Xiaoyu Wei
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, PR China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China
| | - Yanyan Shi
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, PR China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China
| | - Dafeng Liang
- Institute of Bioengineering, Guangdong Academy of Sciences, Guangzhou, 510316, Guangdong, PR China
| | - Mingfeng Cao
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, PR China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China
- Corresponding author. Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, PR China.
| | - Ning He
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, PR China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China
- Corresponding author. Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, PR China.
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17
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Wang Y, Wei Y, Shang N, Li P. Synergistic Inhibition of Plantaricin E/F and Lactic Acid Against Aeromonas hydrophila LPL-1 Reveals the Novel Potential of Class IIb Bacteriocin. Front Microbiol 2022; 13:774184. [PMID: 35242114 PMCID: PMC8886044 DOI: 10.3389/fmicb.2022.774184] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 01/04/2022] [Indexed: 01/15/2023] Open
Abstract
Plantaricin E/F (PlnEF) is a pair of two-component class IIb bacteriocin produced by lactic acid bacteria. PlnEF commonly displays potent antimicrobial activity against certain Gram-positive organisms. In this study, we investigated the synergistic activity of PlnEF combined with lactic acid against Gram-negative food and aquaculture potential pathogen Aeromonas hydrophila LPL-1, which is naturally resistant to PlnEF. We applied SDS-PAGE, wavelength-scanning, laser confocal microscopy, flow cytometer, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and two-dimensional electrophoresis to investigate their synergistic inhibitory activities. The results showed that L-lactic acid drove the release of LPS from A. hydrophila, making it possible for PlnEF to contact the inner cell membrane of A. hydrophila. Besides, co-treatment of lactic acid and PlnEF caused severe morphological and intracellular changes of A. hydrophila, including blebs on the cell surface, abnormal cell elongation, inner membrane disruption, pore-forming through the outer and inner membrane, coagulation of the cytoplasm, and structural transformation of DNA. Protein profile analysis revealed that combined treatment of lactic acid and PlnEF inhibited the energy metabolism, protein synthesis, protein folding, and DNA replication in A. hydrophila. These findings proved that PlnEF combined with lactic acid was efficient against A. hydrophila and shed light on bacteriocin’s potential and a new inhibition mechanism against A. hydrophila.
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Affiliation(s)
- Yang Wang
- Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.,Tianjin Key Laboratory of Aqua-Ecology and Aquaculture College of Fisheries, Tianjin Agricultural University, Tianjin, China
| | - Yunlu Wei
- Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.,School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, China
| | - Nan Shang
- College of Engineering, China Agricultural University, Beijing, China.,Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, China
| | - Pinglan Li
- Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.,Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, China
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18
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Magnesium rescues the morphology of Bacillus subtilis mreB mutants through its inhibitory effect on peptidoglycan hydrolases. Sci Rep 2022; 12:1137. [PMID: 35064120 PMCID: PMC8782873 DOI: 10.1038/s41598-021-04294-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 12/06/2021] [Indexed: 02/04/2023] Open
Abstract
Cell wall homeostasis in bacteria is tightly regulated by balanced synthesis and degradation of peptidoglycan (PG), allowing cells to expand their sacculus during growth while maintaining physical integrity. In rod-shaped bacteria, actin-like MreB proteins are key players of the PG elongation machinery known as the Rod complex. In the Gram-positive model bacterium Bacillus subtilis depletion of the essential MreB leads to loss of rod shape and cell lysis. However, millimolar concentrations of magnesium in the growth medium rescue the viability and morphological defects of mreB mutants by an unknown mechanism. Here, we used a combination of cytological, biochemical and biophysical approaches to investigate the cell surface properties of mreB null mutant cells and the interactions of Mg2+ with the cell wall of B. subtilis. We show that ∆mreB cells have rougher and softer surfaces, and changes in PG composition indicative of increased DL- and DD-endopeptidase activities as well as increased deacetylation of the sugar moieties. Increase in DL-endopeptidase activity is mitigated by excess Mg2+ while DD-endopeptidase activity remains high. Visualization of PG degradation in pulse-chase experiments showed anisotropic PG hydrolase activity along the sidewalls of ∆mreB cells, in particular at the sites of increased cell width and bulging, while PG synthesis remained isotropic. Overall, our data support a model in which divalent cations maintain rod shape in ∆mreB cells by inhibiting PG hydrolases, possibly through the formation of crosslinks with carboxyl groups of the PG meshwork that affect the capacity of PG hydrolases to act on their substrate.
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19
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Alcorlo M, Martínez-Caballero S, Molina R, Hermoso JA. Regulation of Lytic Machineries by the FtsEX Complex in the Bacterial Divisome. Subcell Biochem 2022; 99:285-315. [PMID: 36151380 DOI: 10.1007/978-3-031-00793-4_9] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The essential membrane complex FtsE/FtsX (FtsEX), belonging to the ABC transporter superfamily and widespread among bacteria, plays a relevant function in some crucial cell wall remodeling processes such as cell division, elongation, or sporulation. FtsEX plays a double role by recruiting proteins to the divisome apparatus and by regulating lytic activity of the cell wall hydrolases required for daughter cell separation. Interestingly, FtsEX does not act as a transporter but uses the ATPase activity of FtsE to mechanically transmit a signal from the cytosol, through the membrane, to the periplasm that activates the attached hydrolases. While the complete molecular details of such mechanism are not yet known, evidence has been recently reported that clarify essential aspects of this complex system. In this chapter we will present recent structural advances on this topic. The three-dimensional structure of FtsE, FtsX, and some of the lytic enzymes or their cognate regulators revealed an unexpected scenario in which a delicate set of intermolecular interactions, conserved among different bacterial genera, could be at the core of this regulatory mechanism providing exquisite control in both space and time of this central process to assist bacterial survival.
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Affiliation(s)
- Martín Alcorlo
- Department of Crystallography and Structural Biology, Institute of Physical Chemistry "Rocasolano", CSIC, Madrid, Spain
| | - Siseth Martínez-Caballero
- Department of Crystallography and Structural Biology, Institute of Physical Chemistry "Rocasolano", CSIC, Madrid, Spain
- Department of Chemistry of Biomacromolecules, Universidade Nacional Autonoma de Mexico, Ciudad de México, Mexico
| | - Rafael Molina
- Department of Crystallography and Structural Biology, Institute of Physical Chemistry "Rocasolano", CSIC, Madrid, Spain
| | - Juan A Hermoso
- Department of Crystallography and Structural Biology, Institute of Physical Chemistry "Rocasolano", CSIC, Madrid, Spain.
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20
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Abstract
Most bacteria are surrounded by a peptidoglycan cell wall that defines their shape and protects them from osmotic lysis. The expansion and division of this structure therefore plays an integral role in bacterial growth and division. Additionally, the biogenesis of the peptidoglycan layer is the target of many of our most effective antibiotics. Thus, a better understanding of how the cell wall is built will enable the development of new therapies to combat the rise of drug-resistant bacterial infections. This review covers recent advances in defining the mechanisms involved in assembling the peptidoglycan layer with an emphasis on discoveries related to the function and regulation of the cell elongation and division machineries in the model organisms Escherichia coli and Bacillus subtilis. Expected final online publication date for the Annual Review of Microbiology, Volume 75 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Patricia D A Rohs
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA; .,Current affiliation: Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Thomas G Bernhardt
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA; .,Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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21
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Ser/Thr Kinase-Dependent Phosphorylation of the Peptidoglycan Hydrolase CwlA Controls Its Export and Modulates Cell Division in Clostridioides difficile. mBio 2021; 12:mBio.00519-21. [PMID: 34006648 PMCID: PMC8262956 DOI: 10.1128/mbio.00519-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Cell growth and division require a balance between synthesis and hydrolysis of the peptidoglycan (PG). Inhibition of PG synthesis or uncontrolled PG hydrolysis can be lethal for the cells, making it imperative to control peptidoglycan hydrolase (PGH) activity. The synthesis or activity of several key enzymes along the PG biosynthetic pathway is controlled by the Hanks-type serine/threonine kinases (STKs). In Gram-positive bacteria, inactivation of genes encoding STKs is associated with a range of phenotypes, including cell division defects and changes in cell wall metabolism, but only a few kinase substrates and associated mechanisms have been identified. We previously demonstrated that STK-PrkC plays an important role in cell division, cell wall metabolism, and resistance to antimicrobial compounds in the human enteropathogen Clostridioides difficile In this work, we characterized a PG hydrolase, CwlA, which belongs to the NlpC/P60 family of endopeptidases and hydrolyses cross-linked PG between daughter cells to allow cell separation. We identified CwlA as the first PrkC substrate in C. difficile We demonstrated that PrkC-dependent phosphorylation inhibits CwlA export, thereby controlling hydrolytic activity in the cell wall. High levels of CwlA at the cell surface led to cell elongation, whereas low levels caused cell separation defects. Thus, we provided evidence that the STK signaling pathway regulates PGH homeostasis to precisely control PG hydrolysis during cell division.IMPORTANCE Bacterial cells are encased in a PG exoskeleton that helps to maintain cell shape and confers physical protection. To allow bacterial growth and cell separation, PG needs to be continuously remodeled by hydrolytic enzymes that cleave PG at critical sites. How these enzymes are regulated remains poorly understood. We identify a new PG hydrolase involved in cell division, CwlA, in the enteropathogen C. difficile Lack or accumulation of CwlA at the bacterial surface is responsible for a division defect, while its accumulation in the absence of PrkC also increases susceptibility to antimicrobial compounds targeting the cell wall. CwlA is a substrate of the kinase PrkC in C. difficile PrkC-dependent phosphorylation controls the export of CwlA, modulating its levels and, consequently, its activity in the cell wall. This work provides a novel regulatory mechanism by STK in tightly controlling protein export.
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22
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Class A Penicillin-Binding Protein-Mediated Cell Wall Synthesis Promotes Structural Integrity during Peptidoglycan Endopeptidase Insufficiency in Vibrio cholerae. mBio 2021; 12:mBio.03596-20. [PMID: 33824203 PMCID: PMC8092314 DOI: 10.1128/mbio.03596-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The bacterial cell wall is composed primarily of peptidoglycan (PG), a poly-aminosugar that is essential to sustain cell shape, growth, and structural integrity. PG is synthesized by class A/B penicillin-binding proteins (a/bPBPs) and shape, elongation, division, and sporulation (SEDS) proteins like RodA (as part of the Rod system cell elongation machinery) and degraded by "autolytic" enzymes to accommodate growth processes. It is thought that autolysins (particularly endopeptidases [EPs]) are required for PG synthesis and incorporation by creating gaps that are patched and paved by PG synthases, but the exact relationship between autolysins and PG synthesis remains incompletely understood. Here, we have probed the consequences of EP depletion for PG synthesis in the diarrheal pathogen Vibrio cholerae We found that EP depletion resulted in severe morphological and division defects, but these cells continued to increase in mass and aberrantly incorporated new cell wall material. Mass increase proceeded in the presence of Rod system inhibitors, but cells lysed upon inhibition of aPBPs, suggesting that aPBPs are required for structural integrity under these conditions. The Rod system, although not essential for the observed mass increase, remained functional even after prolonged EP depletion. Last, heterologous expression of an EP from Neisseria gonorrhoeae fully complemented growth and morphology of an EP-insufficient V. cholerae, highlighting the possibility that the PG synthases may not necessarily function via direct interaction with EPs. Overall, our findings suggest that during EP insufficiency in V. cholerae, aPBPs become essential for structural integrity while the Rod system is unable to promote proper cell expansion.IMPORTANCE Synthesis and turnover of the bacterial cell wall must be tightly coordinated to avoid structural integrity failure and cell death. Details of this coordination are poorly understood, particularly if and how cell wall turnover enzymes are required for the activity of the different cell wall synthesis machines, the aPBPs and the Rod system. Our results suggest that in Vibrio cholerae, one class of turnover enzymes, the endopeptidases, are necessary for proper cell elongation and division. aPBPs become essential for maintaining structural integrity during EP insufficiency, while the Rod system remains active but contributes little to cell expansion under these conditions. Our results suggest that aPBPs are more versatile than the Rod system in their ability to recognize cell wall gaps formed by autolysins other than the major endopeptidases, adding to our understanding of the coordination between autolysins and cell wall synthases. A detailed understanding of autolysin biology may promote the development of antibiotics that target these essential turnover processes.
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23
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Rismondo J, Schulz LM. Not Just Transporters: Alternative Functions of ABC Transporters in Bacillus subtilis and Listeria monocytogenes. Microorganisms 2021; 9:microorganisms9010163. [PMID: 33450852 PMCID: PMC7828314 DOI: 10.3390/microorganisms9010163] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/07/2021] [Accepted: 01/10/2021] [Indexed: 12/24/2022] Open
Abstract
ATP-binding cassette (ABC) transporters are usually involved in the translocation of their cognate substrates, which is driven by ATP hydrolysis. Typically, these transporters are required for the import or export of a wide range of substrates such as sugars, ions and complex organic molecules. ABC exporters can also be involved in the export of toxic compounds such as antibiotics. However, recent studies revealed alternative detoxification mechanisms of ABC transporters. For instance, the ABC transporter BceAB of Bacillus subtilis seems to confer resistance to bacitracin via target protection. In addition, several transporters with functions other than substrate export or import have been identified in the past. Here, we provide an overview of recent findings on ABC transporters of the Gram-positive organisms B. subtilis and Listeria monocytogenes with transport or regulatory functions affecting antibiotic resistance, cell wall biosynthesis, cell division and sporulation.
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24
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Hinzke T, Kleiner M, Meister M, Schlüter R, Hentschker C, Pané-Farré J, Hildebrandt P, Felbeck H, Sievert SM, Bonn F, Völker U, Becher D, Schweder T, Markert S. Bacterial symbiont subpopulations have different roles in a deep-sea symbiosis. eLife 2021; 10:58371. [PMID: 33404502 PMCID: PMC7787665 DOI: 10.7554/elife.58371] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 12/05/2020] [Indexed: 12/13/2022] Open
Abstract
The hydrothermal vent tubeworm Riftia pachyptila hosts a single 16S rRNA phylotype of intracellular sulfur-oxidizing symbionts, which vary considerably in cell morphology and exhibit a remarkable degree of physiological diversity and redundancy, even in the same host. To elucidate whether multiple metabolic routes are employed in the same cells or rather in distinct symbiont subpopulations, we enriched symbionts according to cell size by density gradient centrifugation. Metaproteomic analysis, microscopy, and flow cytometry strongly suggest that Riftia symbiont cells of different sizes represent metabolically dissimilar stages of a physiological differentiation process: While small symbionts actively divide and may establish cellular symbiont-host interaction, large symbionts apparently do not divide, but still replicate DNA, leading to DNA endoreduplication. Moreover, in large symbionts, carbon fixation and biomass production seem to be metabolic priorities. We propose that this division of labor between smaller and larger symbionts benefits the productivity of the symbiosis as a whole.
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Affiliation(s)
- Tjorven Hinzke
- Institute of Pharmacy, University of Greifswald, Greifswald, Germany.,Institute of Marine Biotechnology, Greifswald, Germany.,Energy Bioengineering Group, University of Calgary, Calgary, Canada
| | - Manuel Kleiner
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, United States
| | - Mareike Meister
- Institute of Microbiology, University of Greifswald, Greifswald, Germany.,Leibniz Institute for Plasma Science and Technology, Greifswald, Germany
| | - Rabea Schlüter
- Imaging Center of the Department of Biology, University of Greifswald, Greifswald, Germany
| | - Christian Hentschker
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Jan Pané-Farré
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany
| | - Petra Hildebrandt
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Horst Felbeck
- Scripps Institution of Oceanography, University of California San Diego, San Diego, United States
| | - Stefan M Sievert
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, United States
| | - Florian Bonn
- Institute of Biochemistry, University Hospital, Goethe University School of Medicine Frankfurt, Frankfurt, Germany
| | - Uwe Völker
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Dörte Becher
- Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Thomas Schweder
- Institute of Pharmacy, University of Greifswald, Greifswald, Germany.,Institute of Marine Biotechnology, Greifswald, Germany
| | - Stephanie Markert
- Institute of Pharmacy, University of Greifswald, Greifswald, Germany.,Institute of Marine Biotechnology, Greifswald, Germany
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25
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Dörr T. Understanding tolerance to cell wall-active antibiotics. Ann N Y Acad Sci 2020; 1496:35-58. [PMID: 33274447 PMCID: PMC8359209 DOI: 10.1111/nyas.14541] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 11/02/2020] [Accepted: 11/04/2020] [Indexed: 12/19/2022]
Abstract
Antibiotic tolerance-the ability of bacteria to survive for an extended time in the presence of bactericidal antibiotics-is an understudied contributor to antibiotic treatment failure. Herein, I review the manifestations, mechanisms, and clinical relevance of tolerance to cell wall-active (CWA) antibiotics, one of the most important groups of antibiotics at the forefront of clinical use. I discuss definitions of tolerance and assays for tolerance detection, comprehensively discuss the mechanism of action of β-lactams and other CWA antibiotics, and then provide an overview of how cells mitigate the potentially lethal effects of CWA antibiotic-induced cell damage to become tolerant. Lastly, I discuss evidence for a role of CWA antibiotic tolerance in clinical antibiotic treatment failure.
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Affiliation(s)
- Tobias Dörr
- Weill Institute for Cell and Molecular Biology, Department of Microbiology, and Cornell Institute of Host-Pathogen Interactions and Disease, Cornell University, Ithaca, New York
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DrpB (YedR) Is a Nonessential Cell Division Protein in Escherichia coli. J Bacteriol 2020; 202:JB.00284-20. [PMID: 32900831 PMCID: PMC7648144 DOI: 10.1128/jb.00284-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 09/02/2020] [Indexed: 12/11/2022] Open
Abstract
A thorough understanding of bacterial cell division requires identifying and characterizing all of the proteins that participate in this process. Our discovery of DrpB brings us one step closer to this goal in E. coli. We report that the small Escherichia coli membrane protein DrpB (formerly YedR) is involved in cell division. We discovered DrpB in a screen for multicopy suppressors of a ΔftsEX mutation that prevents divisome assembly when cells are plated on low ionic strength medium, such as lysogeny broth without NaCl. Characterization of DrpB revealed that (i) translation initiates at an ATG annotated as codon 22 rather than the GTG annotated as codon 1, (ii) DrpB localizes to the septal ring when cells are grown in medium of low ionic strength but localization is greatly reduced in medium of high ionic strength, (iii) overproduction of DrpB in a ΔftsEX mutant background improves recruitment of the septal peptidoglycan synthase FtsI, implying multicopy suppression works by rescuing septal ring assembly, (iv) a ΔdrpB mutant divides quite normally, but a ΔdrpB ΔdedD double mutant has a strong division and viability defect, albeit only in medium of high ionic strength, and (v) DrpB homologs are found in E. coli and a few closely related enteric bacteria, but not outside this group. In sum, DrpB is a poorly conserved nonessential division protein that improves the efficiency of cytokinesis under suboptimal conditions. Proteins like DrpB are likely to be a widespread feature of the bacterial cell division apparatus, but they are easily overlooked because mutants lack obvious shape defects. IMPORTANCE A thorough understanding of bacterial cell division requires identifying and characterizing all of the proteins that participate in this process. Our discovery of DrpB brings us one step closer to this goal in E. coli.
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Cell morphology maintenance in Bacillus subtilis through balanced peptidoglycan synthesis and hydrolysis. Sci Rep 2020; 10:17910. [PMID: 33087775 PMCID: PMC7578834 DOI: 10.1038/s41598-020-74609-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/28/2020] [Indexed: 01/12/2023] Open
Abstract
The peptidoglycan layer is responsible for maintaining bacterial cell shape and permitting cell division. Cell wall growth is facilitated by peptidoglycan synthases and hydrolases and is potentially modulated by components of the central carbon metabolism. In Bacillus subtilis, UgtP synthesises the glucolipid precursor for lipoteichoic acid and has been suggested to function as a metabolic sensor governing cell size. Here we show that ugtP mutant cells have increased levels of cell wall precursors and changes in their peptidoglycan that suggest elevated DL-endopeptidase activity. The additional deletion of lytE, encoding a DL-endopeptidase important for cell elongation, in the ugtP mutant background produced cells with severe shape defects. Interestingly, the ugtP lytE mutant recovered normal rod-shape by acquiring mutations that decreased the expression of the peptidoglycan synthase PBP1. Together our results suggest that cells lacking ugtP must re-adjust the balance between peptidoglycan synthesis and hydrolysis to maintain proper cell morphology.
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28
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Structural Characterization of the Essential Cell Division Protein FtsE and Its Interaction with FtsX in Streptococcus pneumoniae. mBio 2020; 11:mBio.01488-20. [PMID: 32873757 PMCID: PMC7468199 DOI: 10.1128/mbio.01488-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Bacterial cell division is a central process that requires exquisite orchestration of both the cell wall biosynthetic and lytic machineries. The essential membrane complex FtsEX, widely conserved across bacteria, plays a central role by recruiting proteins to the divisome apparatus and by regulating periplasmic muralytic activity from the cytosol. FtsEX is a member of the type VII family of the ABC-superfamily, but instead of being a transporter, it couples the ATP hydrolysis catalyzed by FtsE to mechanically transduce a conformational signal that provokes the activation of peptidoglycan (PG) hydrolases. So far, no structural information is available for FtsE. Here, we provide the structural characterization of FtsE, confirming its ATPase nature and revealing regions with high structural plasticity which are key for FtsE binding to FtsX. The complementary binding region in FtsX has also been identified and validated in vivo. Our results provide evidence on how the difference between the ATP/ADP-bound states in FtsE would dramatically alter the interaction of FtsEX with the PG hydrolase PcsB in pneumococcal division. FtsEX is a membrane complex widely conserved across diverse bacterial genera and involved in critical processes such as recruitment of division proteins and in spatial and temporal regulation of muralytic activity during cell division or sporulation. FtsEX is a member of the ABC transporter superfamily. The component FtsX is an integral membrane protein, whereas FtsE is an ATPase and is required for the transmission of a conformational signal from the cytosol through the membrane to regulate the activity of cell wall hydrolases in the periplasm. Both proteins are essential in the major human respiratory pathogenic bacterium Streptococcus pneumoniae, and FtsX interacts with the modular peptidoglycan hydrolase PcsB at the septum. Here, we report high-resolution structures of pneumococcal FtsE bound to different nucleotides. Structural analysis revealed that FtsE contains all the conserved structural motifs associated with ATPase activity and afforded interpretation of the in vivo dimeric arrangement in both the ADP and ATP states. Interestingly, three specific FtsE regions with high structural plasticity were identified that shape the cavity in which the cytosolic region of FtsX would be inserted. The residues corresponding to the FtsX coupling helix, responsible for contacting FtsE, were identified and validated by in vivo mutagenesis studies showing that this interaction is essential for cell growth and proper morphology.
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29
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Abstract
Bacteria surround their cell membrane with a net-like peptidoglycan layer, called sacculus, to protect the cell from bursting and maintain its cell shape. Sacculus growth during elongation and cell division is mediated by dynamic and transient multiprotein complexes, the elongasome and divisome, respectively. In this Review we present our current understanding of how peptidoglycan synthases are regulated by multiple and specific interactions with cell morphogenesis proteins that are linked to a dynamic cytoskeletal protein, either the actin-like MreB or the tubulin-like FtsZ. Several peptidoglycan synthases and hydrolases require activation by outer-membrane-anchored lipoproteins. We also discuss how bacteria achieve robust cell wall growth under different conditions and stresses by maintaining multiple peptidoglycan enzymes and regulators as well as different peptidoglycan growth mechanisms, and we present the emerging role of LD-transpeptidases in peptidoglycan remodelling.
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30
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Morphology engineering: a new strategy to construct microbial cell factories. World J Microbiol Biotechnol 2020; 36:127. [PMID: 32712725 DOI: 10.1007/s11274-020-02903-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 07/14/2020] [Indexed: 10/23/2022]
Abstract
Currently, synthetic biology approaches have been developed for constructing microbial cell factories capable of efficient synthesis of high value-added products. Most studies have focused on the construction of novel biosynthetic pathways and their regulatory processes. Morphology engineering has recently been proposed as a novel strategy for constructing efficient microbial cell factories, which aims at controlling cell shape and cell division pattern by manipulating the cell morphology-related genes. Morphology engineering strategies have been exploited for improving bacterial growth rate, enlarging cell volume and simplifying downstream separation. This mini-review summarizes cell morphology-related proteins and their function, current advances in manipulation tools and strategies of morphology engineering, and practical applications of morphology engineering for enhanced production of intracellular product polyhydroxyalkanoate and extracellular products. Furthermore, current limitations and the future development direction using morphology engineering are proposed.
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31
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Silber N, Matos de Opitz CL, Mayer C, Sass P. Cell division protein FtsZ: from structure and mechanism to antibiotic target. Future Microbiol 2020; 15:801-831. [DOI: 10.2217/fmb-2019-0348] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Antimicrobial resistance to virtually all clinically applied antibiotic classes severely limits the available options to treat bacterial infections. Hence, there is an urgent need to develop and evaluate new antibiotics and targets with resistance-breaking properties. Bacterial cell division has emerged as a new antibiotic target pathway to counteract multidrug-resistant pathogens. New approaches in antibiotic discovery and bacterial cell biology helped to identify compounds that either directly interact with the major cell division protein FtsZ, thereby perturbing the function and dynamics of the cell division machinery, or affect the structural integrity of FtsZ by inducing its degradation. The impressive antimicrobial activities and resistance-breaking properties of certain compounds validate the inhibition of bacterial cell division as a promising strategy for antibiotic intervention.
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Affiliation(s)
- Nadine Silber
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology & Infection Medicine, University of Tübingen, Auf der Morgenstelle 28, Tübingen 72076, Germany
| | - Cruz L Matos de Opitz
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology & Infection Medicine, University of Tübingen, Auf der Morgenstelle 28, Tübingen 72076, Germany
| | - Christian Mayer
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology & Infection Medicine, University of Tübingen, Auf der Morgenstelle 28, Tübingen 72076, Germany
| | - Peter Sass
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology & Infection Medicine, University of Tübingen, Auf der Morgenstelle 28, Tübingen 72076, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Tübingen 72076, Germany
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32
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Shin JH, Sulpizio AG, Kelley A, Alvarez L, Murphy SG, Fan L, Cava F, Mao Y, Saper MA, Dörr T. Structural basis of peptidoglycan endopeptidase regulation. Proc Natl Acad Sci U S A 2020; 117:11692-11702. [PMID: 32393643 PMCID: PMC7261138 DOI: 10.1073/pnas.2001661117] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Most bacteria surround themselves with a cell wall, a strong meshwork consisting primarily of the polymerized aminosugar peptidoglycan (PG). PG is essential for structural maintenance of bacterial cells, and thus for viability. PG is also constantly synthesized and turned over; the latter process is mediated by PG cleavage enzymes, for example, the endopeptidases (EPs). EPs themselves are essential for growth but also promote lethal cell wall degradation after exposure to antibiotics that inhibit PG synthases (e.g., β-lactams). Thus, EPs are attractive targets for novel antibiotics and their adjuvants. However, we have a poor understanding of how these enzymes are regulated in vivo, depriving us of novel pathways for the development of such antibiotics. Here, we have solved crystal structures of the LysM/M23 family peptidase ShyA, the primary EP of the cholera pathogen Vibrio cholerae Our data suggest that ShyA assumes two drastically different conformations: a more open form that allows for substrate binding and a closed form, which we predicted to be catalytically inactive. Mutations expected to promote the open conformation caused enhanced activity in vitro and in vivo, and these results were recapitulated in EPs from the divergent pathogens Neisseria gonorrheae and Escherichia coli Our results suggest that LysM/M23 EPs are regulated via release of the inhibitory Domain 1 from the M23 active site, likely through conformational rearrangement in vivo.
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Affiliation(s)
- Jung-Ho Shin
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - Alan G Sulpizio
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - Aaron Kelley
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109-5606
| | - Laura Alvarez
- The Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden
| | - Shannon G Murphy
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
- Department of Microbiology, Cornell University, Ithaca, NY 14853
| | - Lixin Fan
- Basic Science Program, Frederick National Laboratory for Cancer Research, SAXS Core Facility of the National Cancer Institute, Frederick, MD 21702
| | - Felipe Cava
- The Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden
| | - Yuxin Mao
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - Mark A Saper
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109-5606
| | - Tobias Dörr
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853;
- Department of Microbiology, Cornell University, Ithaca, NY 14853
- Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, NY 14853
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33
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Culp EJ, Waglechner N, Wang W, Fiebig-Comyn AA, Hsu YP, Koteva K, Sychantha D, Coombes BK, Van Nieuwenhze MS, Brun YV, Wright GD. Evolution-guided discovery of antibiotics that inhibit peptidoglycan remodelling. Nature 2020; 578:582-587. [DOI: 10.1038/s41586-020-1990-9] [Citation(s) in RCA: 121] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 12/12/2019] [Indexed: 11/09/2022]
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34
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Do T, Page JE, Walker S. Uncovering the activities, biological roles, and regulation of bacterial cell wall hydrolases and tailoring enzymes. J Biol Chem 2020; 295:3347-3361. [PMID: 31974163 DOI: 10.1074/jbc.rev119.010155] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Bacteria account for 1000-fold more biomass than humans. They vary widely in shape and size. The morphological diversity of bacteria is due largely to the different peptidoglycan-based cell wall structures that encase bacterial cells. Although the basic structure of peptidoglycan is highly conserved, consisting of long glycan strands that are cross-linked by short peptide chains, the mature cell wall is chemically diverse. Peptidoglycan hydrolases and cell wall-tailoring enzymes that regulate glycan strand length, the degree of cross-linking, and the addition of other modifications to peptidoglycan are central in determining the final architecture of the bacterial cell wall. Historically, it has been difficult to biochemically characterize these enzymes that act on peptidoglycan because suitable peptidoglycan substrates were inaccessible. In this review, we discuss fundamental aspects of bacterial cell wall synthesis, describe the regulation and diverse biochemical and functional activities of peptidoglycan hydrolases, and highlight recently developed methods to make and label defined peptidoglycan substrates. We also review how access to these substrates has now enabled biochemical studies that deepen our understanding of how bacterial cell wall enzymes cooperate to build a mature cell wall. Such improved understanding is critical to the development of new antibiotics that disrupt cell wall biogenesis, a process essential to the survival of bacteria.
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Affiliation(s)
- Truc Do
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115
| | - Julia E Page
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115
| | - Suzanne Walker
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115.
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35
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Do T, Schaefer K, Santiago AG, Coe KA, Fernandes PB, Kahne D, Pinho MG, Walker S. Staphylococcus aureus cell growth and division are regulated by an amidase that trims peptides from uncrosslinked peptidoglycan. Nat Microbiol 2020; 5:291-303. [PMID: 31932712 PMCID: PMC7046134 DOI: 10.1038/s41564-019-0632-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Accepted: 11/05/2019] [Indexed: 12/16/2022]
Abstract
Bacteria are protected by a polymer of peptidoglycan that serves as an exoskeleton1. In Staphylococcus aureus, the peptidoglycan assembly enzymes relocate during the cell cycle from the periphery, where they are active during growth, to the division site where they build the partition between daughter cells2-4. But how peptidoglycan synthesis is regulated throughout the cell cycle is poorly understood5,6. Here, we used a transposon screen to identify a membrane protein complex that spatially regulates S. aureus peptidoglycan synthesis. This complex consists of an amidase that removes stem peptides from uncrosslinked peptidoglycan and a partner protein that controls its activity. Amidases typically hydrolyse crosslinked peptidoglycan between daughter cells so that they can separate7. However, this amidase controls cell growth. In its absence, peptidoglycan synthesis becomes spatially dysregulated, which causes cells to grow so large that cell division is defective. We show that the cell growth and division defects due to loss of this amidase can be mitigated by attenuating the polymerase activity of the major S. aureus peptidoglycan synthase. Our findings lead to a model wherein the amidase complex regulates the density of peptidoglycan assembly sites to control peptidoglycan synthase activity at a given subcellular location. Removal of stem peptides from peptidoglycan at the cell periphery promotes peptidoglycan synthase relocation to midcell during cell division. This mechanism ensures that cell expansion is properly coordinated with cell division.
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Affiliation(s)
- Truc Do
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Kaitlin Schaefer
- Department of Microbiology, Harvard Medical School, Boston, MA, USA.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | | | - Kathryn A Coe
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Pedro B Fernandes
- Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Daniel Kahne
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Mariana G Pinho
- Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Suzanne Walker
- Department of Microbiology, Harvard Medical School, Boston, MA, USA.
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36
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Pichoff S, Du S, Lutkenhaus J. Roles of FtsEX in cell division. Res Microbiol 2019; 170:374-380. [PMID: 31376483 PMCID: PMC6899183 DOI: 10.1016/j.resmic.2019.07.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 07/09/2019] [Accepted: 07/16/2019] [Indexed: 02/04/2023]
Abstract
FtsEX is a member of a small subclass of ABC transporters that uses mechano-transmission to perform work in the periplasm. FtsEX controls periplasmic peptidoglycan (PG) hydrolase activities in many Gram negative and positive organisms to ensure the safe separation of daughter cells during division. In these organisms FtsEX localizes to the Z ring and uses its ATPase activity to regulate its periplasmic effectors. In Escherichia coli, FtsEX also participates in building the divisome and coordinates PG synthesis with PG hydrolysis. This review discusses studies that are beginning to elucidate the mechanisms of FtsEX's various roles in cell division.
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Affiliation(s)
- Sebastien Pichoff
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Shishen Du
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Joe Lutkenhaus
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, KS, 66160, USA.
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37
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Brunet YR, Wang X, Rudner DZ. SweC and SweD are essential co-factors of the FtsEX-CwlO cell wall hydrolase complex in Bacillus subtilis. PLoS Genet 2019; 15:e1008296. [PMID: 31437162 PMCID: PMC6705773 DOI: 10.1371/journal.pgen.1008296] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 07/08/2019] [Indexed: 01/10/2023] Open
Abstract
The peptidoglycan (PG) sacculus is composed of long glycan strands cross-linked together by short peptides forming a covalently closed meshwork that protects the bacterial cell from osmotic lysis and specifies its shape. PG hydrolases play essential roles in remodeling this three-dimensional network during growth and division but how these autolytic enzymes are regulated remains poorly understood. The FtsEX ABC transporter-like complex has emerged as a broadly conserved regulatory module in controlling cell wall hydrolases in diverse bacterial species. In most characterized examples, this complex regulates distinct PG hydrolases involved in cell division and is intimately associated with the cytokinetic machinery called the divisome. However, in the gram-positive bacterium Bacillus subtilis the FtsEX complex is required for cell wall elongation where it regulates the PG hydrolase CwlO that acts along the lateral cell wall. To investigate whether additional factors are required for FtsEX function outside the divisome, we performed a synthetic lethal screen taking advantage of the conditional essentiality of CwlO. This screen identified two uncharacterized factors (SweD and SweC) that are required for CwlO activity. We demonstrate that these proteins reside in a membrane complex with FtsX and that amino acid substitutions in residues adjacent to the ATPase domain of FtsE partially bypass the requirement for them. Collectively our data indicate that SweD and SweC function as essential co-factors of FtsEX in controlling CwlO during cell wall elongation. We propose that factors analogous to SweDC function to support FtsEX activity outside the divisome in other bacteria.
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Affiliation(s)
- Yannick R. Brunet
- Department of Microbiology, Harvard Medical School, Boston, MA, United States of America
| | - Xindan Wang
- Department of Microbiology, Harvard Medical School, Boston, MA, United States of America
| | - David Z. Rudner
- Department of Microbiology, Harvard Medical School, Boston, MA, United States of America
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38
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Duchêne MC, Rolain T, Knoops A, Courtin P, Chapot-Chartier MP, Dufrêne YF, Hallet BF, Hols P. Distinct and Specific Role of NlpC/P60 Endopeptidases LytA and LytB in Cell Elongation and Division of Lactobacillus plantarum. Front Microbiol 2019; 10:713. [PMID: 31031721 PMCID: PMC6473061 DOI: 10.3389/fmicb.2019.00713] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 03/21/2019] [Indexed: 11/22/2022] Open
Abstract
Peptidoglycan (PG) is an essential lattice of the bacterial cell wall that needs to be continuously remodeled to allow growth. This task is ensured by the concerted action of PG synthases that insert new material in the pre-existing structure and PG hydrolases (PGHs) that cleave the PG meshwork at critical sites for its processing. Contrasting with Bacillus subtilis that contains more than 35 PGHs, Lactobacillus plantarum is a non-sporulating rod-shaped bacterium that is predicted to possess a minimal set of 12 PGHs. Their role in morphogenesis and cell cycle remains mostly unexplored, except for the involvement of the glucosaminidase Acm2 in cell separation and the NlpC/P60 D, L-endopeptidase LytA in cell shape maintenance. Besides LytA, L. plantarum encodes three additional NlpC/P60 endopeptidases (i.e., LytB, LytC and LytD). The in silico analysis of these four endopeptidases suggests that they could have redundant functions based on their modular organization, forming two pairs of paralogous enzymes. In this work, we investigate the role of each Lyt endopeptidase in cell morphogenesis in order to evaluate their distinct or redundant functions, and eventually their synthetic lethality. We show that the paralogous LytC and LytD enzymes are not required for cell shape maintenance, which may indicate an accessory role such as in PG recycling. In contrast, LytA and LytB appear to be key players of the cell cycle. We show here that LytA is required for cell elongation while LytB is involved in the spatio-temporal regulation of cell division. In addition, both PGHs are involved in the proper positioning of the division site. The absence of LytA activity is responsible for the asymmetrical positioning of septa in round cells while the lack of LytB results in a lateral misplacement of division planes in rod-shaped cells. Finally, we show that the co-inactivation of LytA and LytB is synthetically affecting cell growth, which confirms the key roles played by both enzymes in PG remodeling during the cell cycle of L. plantarum. Based on the large distribution of NlpC/P60 endopeptidases in low-GC Gram-positive bacteria, these enzymes are attractive targets for the discovery of novel antimicrobial compounds.
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Affiliation(s)
- Marie-Clémence Duchêne
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, Louvain-La-Neuve, Belgium
| | - Thomas Rolain
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, Louvain-La-Neuve, Belgium
| | - Adrien Knoops
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, Louvain-La-Neuve, Belgium
| | - Pascal Courtin
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | | | - Yves F Dufrêne
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, Louvain-La-Neuve, Belgium
| | - Bernard F Hallet
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, Louvain-La-Neuve, Belgium
| | - Pascal Hols
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, Louvain-La-Neuve, Belgium
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39
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Crawford MA, Margulieux KR, Singh A, Nakamoto RK, Hughes MA. Mechanistic insights and therapeutic opportunities of antimicrobial chemokines. Semin Cell Dev Biol 2019; 88:119-128. [PMID: 29432954 PMCID: PMC6613794 DOI: 10.1016/j.semcdb.2018.02.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 02/06/2018] [Indexed: 12/27/2022]
Abstract
Chemokines are a family of small proteins best known for their ability to orchestrate immune cell trafficking and recruitment to sites of infection. Their role in promoting host defense is multiplied by a number of additional receptor-dependent biological activities, and most, but not all, chemokines have been found to mediate direct antimicrobial effects against a broad range of microorganisms. The molecular mechanism(s) by which antimicrobial chemokines kill bacteria remains unknown; however, recent observations have expanded our fundamental understanding of chemokine-mediated bactericidal activity to reveal increasingly diverse and complex actions. In the current review, we present and consider mechanistic insights of chemokine-mediated antimicrobial activity against bacteria. We also discuss how contemporary advances are reshaping traditional paradigms and opening up new and innovative avenues of research with translational implications. Towards this end, we highlight a developing framework for leveraging chemokine-mediated bactericidal and immunomodulatory effects to advance pioneering therapeutic approaches for treating bacterial infections, including those caused by multidrug-resistant pathogens.
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Affiliation(s)
- Matthew A Crawford
- Division of Infectious Diseases & International Health, Department of Medicine, University of Virginia, Charlottesville, VA, 22908, USA
| | - Katie R Margulieux
- Department of Enteric Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok 10400, Thailand
| | - Arpita Singh
- Division of Infectious Diseases & International Health, Department of Medicine, University of Virginia, Charlottesville, VA, 22908, USA
| | - Robert K Nakamoto
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, 22908, USA
| | - Molly A Hughes
- Division of Infectious Diseases & International Health, Department of Medicine, University of Virginia, Charlottesville, VA, 22908, USA.
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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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Ramaniuk O, Převorovský M, Pospíšil J, Vítovská D, Kofroňová O, Benada O, Schwarz M, Šanderová H, Hnilicová J, Krásný L. σ I from Bacillus subtilis: Impact on Gene Expression and Characterization of σ I-Dependent Transcription That Requires New Types of Promoters with Extended -35 and -10 Elements. J Bacteriol 2018; 200:e00251-18. [PMID: 29914988 PMCID: PMC6088155 DOI: 10.1128/jb.00251-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 06/09/2018] [Indexed: 11/20/2022] Open
Abstract
The σI sigma factor from Bacillus subtilis is a σ factor associated with RNA polymerase (RNAP) that was previously implicated in adaptation of the cell to elevated temperature. Here, we provide a comprehensive characterization of this transcriptional regulator. By transcriptome sequencing (RNA-seq) of wild-type (wt) and σI-null strains at 37°C and 52°C, we identified ∼130 genes affected by the absence of σI Further analysis revealed that the majority of these genes were affected indirectly by σI The σI regulon, i.e., the genes directly regulated by σI, consists of 16 genes, of which eight (the dhb and yku operons) are involved in iron metabolism. The involvement of σI in iron metabolism was confirmed phenotypically. Next, we set up an in vitro transcription system and defined and experimentally validated the promoter sequence logo that, in addition to -35 and -10 regions, also contains extended -35 and -10 motifs. Thus, σI-dependent promoters are relatively information rich in comparison with most other promoters. In summary, this study supplies information about the least-explored σ factor from the industrially important model organism B. subtilisIMPORTANCE In bacteria, σ factors are essential for transcription initiation. Knowledge about their regulons (i.e., genes transcribed from promoters dependent on these σ factors) is the key for understanding how bacteria cope with the changing environment and could be instrumental for biotechnologically motivated rewiring of gene expression. Here, we characterize the σI regulon from the industrially important model Gram-positive bacterium Bacillus subtilis We reveal that σI affects expression of ∼130 genes, of which 16 are directly regulated by σI, including genes encoding proteins involved in iron homeostasis. Detailed analysis of promoter elements then identifies unique sequences important for σI-dependent transcription. This study thus provides a comprehensive view on this underexplored component of the B. subtilis transcription machinery.
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Affiliation(s)
- Olga Ramaniuk
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
- Department of Genetics and Microbiology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Martin Převorovský
- Department of Cell Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Jiří Pospíšil
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Dragana Vítovská
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Olga Kofroňová
- Laboratory of Molecular Structure Characterization, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Oldřich Benada
- Laboratory of Molecular Structure Characterization, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Marek Schwarz
- Laboratory of Bioinformatics, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Hana Šanderová
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jarmila Hnilicová
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Libor Krásný
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
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Cao M, Feng J, Sirisansaneeyakul S, Song C, Chisti Y. Genetic and metabolic engineering for microbial production of poly-γ-glutamic acid. Biotechnol Adv 2018; 36:1424-1433. [PMID: 29852203 DOI: 10.1016/j.biotechadv.2018.05.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 05/27/2018] [Indexed: 12/15/2022]
Abstract
Poly-γ-glutamic acid (γ-PGA) is a natural biopolymer of glutamic acid. The repeating units of γ-PGA may be derived exclusively from d-glutamic acid, or l-glutamic acid, or both. The monomer units are linked by amide bonds between the α-amino group and the γ-carboxylic acid group. γ-PGA is biodegradable, edible and water-soluble. It has numerous existing and emerging applications in processing of foods, medicines and cosmetics. This review focuses on microbial production of γ-PGA via genetically and metabolically engineered recombinant bacteria. Strategies for improving production of γ-PGA include modification of its biosynthesis pathway, enhancing the production of its precursor (glutamic acid), and preventing loss of the precursor to competing byproducts. These and other strategies are discussed. Heterologous synthesis of γ-PGA in industrial bacterial hosts that do not naturally produce γ-PGA is discussed. Emerging trends and the challenges affecting the production of γ-PGA are reviewed.
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Affiliation(s)
- Mingfeng Cao
- Department of Chemical and Biological Engineering, NSF Center for Biorenewable Chemicals (CBiRC), Iowa State University, Ames, IA 50011-1098, USA
| | - Jun Feng
- Department of Biosystems Engineering, Auburn University, Auburn, AL 36849, USA
| | - Sarote Sirisansaneeyakul
- Department of Biotechnology, Faculty of Agro-Industry, Kasetsart University, Chatuchak, Bangkok 10900, Thailand.
| | - Cunjiang Song
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, Nankai University, Tianjin 300071, China
| | - Yusuf Chisti
- School of Engineering, Massey University, Private Bag 11 222, Palmerston North, New Zealand.
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Takada H, Shiwa Y, Takino Y, Osaka N, Ueda S, Watanabe S, Chibazakura T, Su'etsugu M, Utsumi R, Yoshikawa H. Essentiality of WalRK for growth in Bacillus subtilis and its role during heat stress. MICROBIOLOGY-SGM 2018; 164:670-684. [PMID: 29465029 DOI: 10.1099/mic.0.000625] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
WalRK is an essential two-component signal transduction system that plays a central role in coordinating cell wall synthesis and cell growth in Bacillus subtilis. However, the physiological role of WalRK and its essentiality for growth have not been elucidated. We investigated the behaviour of WalRK during heat stress and its essentiality for cell proliferation. We determined that the inactivation of the walHI genes which encode the negative modulator of WalK, resulted in growth defects and eventual cell lysis at high temperatures. Screening of suppressor mutations revealed that the inactivation of LytE, an dl-endopeptidase, restored the growth of the ΔwalHI mutant at high temperatures. Suppressor mutations that reduced heat induction arising from the walRK regulon were also mapped to the walK ORF. Therefore, we hypothesized that overactivation of LytE affects the phenotype of the ΔwalHI mutant. This hypothesis was corroborated by the overexpression of the negative regulator of LytE, IseA and PdaC, which rescued the growth of the ΔwalHI mutant at high temperatures. Elucidating the cause of the temperature sensitivity of the ΔwalHI mutant could explain the essentiality of WalRK. We proved that the constitutive expression of lytE or cwlO using a synthetic promoter uncouples these expressions from WalRK, and renders WalRK nonessential in the pdaC and iseA mutant backgrounds. We propose that the essentiality of WalRK is derived from the coordination of cell wall metabolism with cell growth by regulating dl-endopeptidase activity under various growth conditions.
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Affiliation(s)
- Hiraku Takada
- Department of Life Science and Research Center for Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo 171-8501, Japan.,Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
| | - Yuh Shiwa
- Genome Research Center, NODAI Research Institute, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
| | - Yuta Takino
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
| | - Natsuki Osaka
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
| | - Shuhei Ueda
- Department of Advanced Bioscience, Graduate School of Agriculture, Kindai University, 3327-204 Nakamachi, Nara-shi, Nara 631-8505, Japan
| | - Satoru Watanabe
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
| | - Taku Chibazakura
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
| | - Masayuki Su'etsugu
- Department of Life Science and Research Center for Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo 171-8501, Japan
| | - Ryutaro Utsumi
- Department of Advanced Bioscience, Graduate School of Agriculture, Kindai University, 3327-204 Nakamachi, Nara-shi, Nara 631-8505, Japan
| | - Hirofumi Yoshikawa
- Genome Research Center, NODAI Research Institute, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan.,Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
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FtsEX-CwlO regulates biofilm formation by a plant-beneficial rhizobacterium Bacillus velezensis SQR9. Res Microbiol 2018; 169:166-176. [PMID: 29427638 DOI: 10.1016/j.resmic.2018.01.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 01/23/2018] [Accepted: 01/29/2018] [Indexed: 12/23/2022]
Abstract
Bacillus velezensis strain SQR9 is a well-investigated rhizobacterium with an outstanding ability to colonize roots, enhance plant growth and suppress soil-borne diseases. The recognition that biofilm formation by plant-beneficial bacteria is crucial for their root colonization and function has resulted in increased interest in understanding molecular mechanisms related to biofilm formation. Here, we report that the gene ftsE, encoding the ATP-binding protein of an FtsEX ABC transporter, is required for efficient SQR9 biofilm formation. FtsEX has been reported to regulate the atolysin CwlO. We provided evidence that FtsEX-CwlO was involved in the regulation of SQR9 biofilm formation; however, this effect has little to do with CwlO autolysin activity. We propose that regulation of biofilm formation by CwlO was exerted through the spo0A pathway, since transcription of spo0A cascade genes was altered and their downstream extracellular matrix genes were downregulated in SQR9 ftsE/cwlO deletion mutants. CwlO was also shown to interact physically with KinB/KinD. CwlO may therefore interact with KinB/KinD to interfere with the spo0A pathway. This study revealed that FtsEX-CwlO plays a previously undiscovered regulatory role in biofilm formation by SQR9 that may enhance root colonization and plant-beneficial functions of SQR9 and other beneficial rhizobacteria as well.
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Guariglia-Oropeza V, Orsi RH, Guldimann C, Wiedmann M, Boor KJ. The Listeria monocytogenes Bile Stimulon under Acidic Conditions Is Characterized by Strain-Specific Patterns and the Upregulation of Motility, Cell Wall Modification Functions, and the PrfA Regulon. Front Microbiol 2018; 9:120. [PMID: 29467736 PMCID: PMC5808219 DOI: 10.3389/fmicb.2018.00120] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 01/18/2018] [Indexed: 11/16/2022] Open
Abstract
Listeria monocytogenes uses a variety of transcriptional regulation strategies to adapt to the extra-host environment, the gastrointestinal tract, and the intracellular host environment. While the alternative sigma factor SigB has been proposed to be a key transcriptional regulator that facilitates L. monocytogenes adaptation to the gastrointestinal environment, the L. monocytogenes' transcriptional response to bile exposure is not well-understood. RNA-seq characterization of the bile stimulon was performed in two L. monocytogenes strains representing lineages I and II. Exposure to bile at pH 5.5 elicited a large transcriptomic response with ~16 and 23% of genes showing differential transcription in 10403S and H7858, respectively. The bile stimulon includes genes involved in motility and cell wall modification mechanisms, as well as genes in the PrfA regulon, which likely facilitate survival during the gastrointestinal stages of infection that follow bile exposure. The fact that bile exposure induced the PrfA regulon, but did not induce further upregulation of the SigB regulon (beyond that expected by exposure to pH 5.5), suggests a model where at the earlier stages of gastrointestinal infection (e.g., acid exposure in the stomach), SigB-dependent gene expression plays an important role. Subsequent exposure to bile induces the PrfA regulon, potentially priming L. monocytogenes for subsequent intracellular infection stages. Some members of the bile stimulon showed lineage- or strain-specific distribution when 27 Listeria genomes were analyzed. Even though sigB null mutants showed increased sensitivity to bile, the SigB regulon was not found to be upregulated in response to bile beyond levels expected by exposure to pH 5.5. Comparison of wildtype and corresponding ΔsigB strains newly identified 26 SigB-dependent genes, all with upstream putative SigB-dependent promoters.
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Affiliation(s)
| | - Renato H Orsi
- Food Safety Laboratory, Department of Food Science, Cornell University, Ithaca, NY, United States
| | - Claudia Guldimann
- Food Safety Laboratory, Department of Food Science, Cornell University, Ithaca, NY, United States
| | - Martin Wiedmann
- Food Safety Laboratory, Department of Food Science, Cornell University, Ithaca, NY, United States
| | - Kathryn J Boor
- Food Safety Laboratory, Department of Food Science, Cornell University, Ithaca, NY, United States
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46
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Zhao H, Patel V, Helmann JD, Dörr T. Don't let sleeping dogmas lie: new views of peptidoglycan synthesis and its regulation. Mol Microbiol 2017; 106:847-860. [PMID: 28975672 DOI: 10.1111/mmi.13853] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2017] [Indexed: 12/24/2022]
Abstract
Bacterial cell wall synthesis is the target for some of our most powerful antibiotics and has thus been the subject of intense research focus for more than 50 years. Surprisingly, we still lack a fundamental understanding of how bacteria build, maintain and expand their cell wall. Due to technical limitations, directly testing hypotheses about the coordination and biochemistry of cell wall synthesis enzymes or architecture has been challenging, and interpretation of data has therefore often relied on circumstantial evidence and implicit assumptions. A number of recent papers have exploited new technologies, like single molecule tracking and real-time, high resolution temporal mapping of cell wall synthesis processes, to address fundamental questions of bacterial cell wall biogenesis. The results have challenged established dogmas and it is therefore timely to integrate new data and old observations into a new model of cell wall biogenesis in rod-shaped bacteria.
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Affiliation(s)
- Heng Zhao
- Department of Microbiology, Cornell University, Ithaca, NY 14853-8101, USA
| | - Vaidehi Patel
- Department of Microbiology, Cornell University, Ithaca, NY 14853-8101, USA
| | - John D Helmann
- Department of Microbiology, Cornell University, Ithaca, NY 14853-8101, USA
| | - Tobias Dörr
- Department of Microbiology, Cornell University, Ithaca, NY 14853-8101, USA.,Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
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47
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Abstract
Bacillus subtilis is the best described member of the Gram positive bacteria. It is a typical rod shaped bacterium and grows by elongation in its long axis, before dividing at mid cell to generate two similar daughter cells. B. subtilis is a particularly interesting model for cell cycle studies because it also carries out a modified, asymmetrical division during endospore formation, which can be simply induced by starvation. Cell growth occurs strictly by elongation of the rod, which maintains a constant diameter at all growth rates. This process involves expansion of the cell wall, requiring intercalation of new peptidoglycan and teichoic acid material, as well as controlled hydrolysis of existing wall material. Actin-like MreB proteins are the key spatial regulators that orchestrate the plethora of enzymes needed for cell elongation, many of which are thought to assemble into functional complexes called elongasomes. Cell division requires a switch in the orientation of cell wall synthesis and is organised by a tubulin-like protein FtsZ. FtsZ forms a ring-like structure at the site of impending division, which is specified by a range of mainly negative regulators. There it recruits a set of dedicated division proteins to form a structure called the divisome, which brings about the process of division. During sporulation, both the positioning and fine structure of the division septum are altered, and again, several dedicated proteins that contribute specifically to this process have been identified. This chapter summarises our current understanding of elongation and division in B. subtilis, with particular emphasis on the cytoskeletal proteins MreB and FtsZ, and highlights where the major gaps in our understanding remain.
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Margulieux KR, Liebov BK, Tirumala VSKKS, Singh A, Bushweller JH, Nakamoto RK, Hughes MA. Bacillus anthracis Peptidoglycan Integrity Is Disrupted by the Chemokine CXCL10 through the FtsE/X Complex. Front Microbiol 2017; 8:740. [PMID: 28496437 PMCID: PMC5406473 DOI: 10.3389/fmicb.2017.00740] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 04/10/2017] [Indexed: 01/07/2023] Open
Abstract
The antimicrobial activity of the chemokine CXCL10 against vegetative cells of Bacillus anthracis occurs via both bacterial FtsE/X-dependent and-independent pathways. Previous studies established that the FtsE/X-dependent pathway was mediated through interaction of the N-terminal region(s) of CXCL10 with a functional FtsE/X complex, while the FtsE/X-independent pathway was mediated through the C-terminal α-helix of CXCL10. Both pathways result in cell lysis and death of B. anthracis. In other bacterial species, it has been shown that FtsE/X is involved in cellular elongation though activation of complex-associated peptidoglycan hydrolases. Thus, we hypothesized that the CXCL10-mediated killing of vegetative cells of B. anthracis through the FtsE/X-dependent pathway resulted from the disruption of peptidoglycan processing. Immunofluorescence microscopy studies using fluorescent peptidoglycan probes revealed that incubation of B. anthracis Sterne (parent) strain with CXCL10 or a C-terminal truncated CXCL10 (CTTC) affected peptidoglycan processing and/or incorporation of precursors into the cell wall. B. anthracis ΔftsX or ftsE(K123A/D481N) mutant strains, which lacked a functional FtsE/X complex, exhibited little to no evidence of disruption in peptidoglycan processing by either CXCL10 or CTTC. Additional studies demonstrated that the B. anthracis parent strain exhibited a statistically significant increase in peptidoglycan release in the presence of either CXCL10 or CTTC. While B. anthracis ΔftsX strain showed increased peptidoglycan release in the presence of CXCL10, no increase was observed with CTTC, suggesting that the FtsE/X-independent pathway was responsible for the activity observed with CXCL10. These results indicate that FtsE/X-dependent killing of vegetative cells of B. anthracis results from a loss of cell wall integrity due to disruption of peptidoglycan processing and suggest that FtsE/X may be an important antimicrobial target to study in the search for alternative microbial therapeutics.
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Affiliation(s)
- Katie R Margulieux
- Division of Infectious Diseases and International Health, Department of Medicine, School of Medicine, University of Virginia, CharlottesvilleVA, USA
| | - Benjamin K Liebov
- Department of Chemistry, University of Virginia, CharlottesvilleVA, USA
| | - Venkata S K K S Tirumala
- Department of Molecular Physiology and Biological Physics, University of Virginia, CharlottesvilleVA, USA
| | - Arpita Singh
- Division of Infectious Diseases and International Health, Department of Medicine, School of Medicine, University of Virginia, CharlottesvilleVA, USA
| | - John H Bushweller
- Department of Molecular Physiology and Biological Physics, University of Virginia, CharlottesvilleVA, USA
| | - Robert K Nakamoto
- Department of Molecular Physiology and Biological Physics, University of Virginia, CharlottesvilleVA, USA
| | - Molly A Hughes
- Division of Infectious Diseases and International Health, Department of Medicine, School of Medicine, University of Virginia, CharlottesvilleVA, USA
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Specific Glucoside Transporters Influence Septal Structure and Function in the Filamentous, Heterocyst-Forming Cyanobacterium Anabaena sp. Strain PCC 7120. J Bacteriol 2017; 199:JB.00876-16. [PMID: 28096449 DOI: 10.1128/jb.00876-16] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 01/12/2017] [Indexed: 12/26/2022] Open
Abstract
When deprived of combined nitrogen, some filamentous cyanobacteria contain two cell types: vegetative cells that fix CO2 through oxygenic photosynthesis and heterocysts that are specialized in N2 fixation. In the diazotrophic filament, the vegetative cells provide the heterocysts with reduced carbon (mainly in the form of sucrose) and heterocysts provide the vegetative cells with combined nitrogen. Septal junctions traverse peptidoglycan through structures known as nanopores and appear to mediate intercellular molecular transfer that can be traced with fluorescent markers, including the sucrose analog esculin (a coumarin glucoside) that is incorporated into the cells. Uptake of esculin by the model heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 was inhibited by the α-glucosides sucrose and maltose. Analysis of Anabaena mutants identified components of three glucoside transporters that move esculin into the cells: GlsC (Alr4781) and GlsP (All0261) are an ATP-binding subunit and a permease subunit of two different ABC transporters, respectively, and HepP (All1711) is a major facilitator superfamily (MFS) protein that was shown previously to be involved in formation of the heterocyst envelope. Transfer of fluorescent markers (especially calcein) between vegetative cells of Anabaena was impaired by mutation of glucoside transporter genes. GlsP and HepP interact in bacterial two-hybrid assays with the septal junction-related protein SepJ, and GlsC was found to be necessary for the formation of a normal number of septal peptidoglycan nanopores and for normal subcellular localization of SepJ. Therefore, beyond their possible role in nutrient uptake in Anabaena, glucoside transporters influence the structure and function of septal junctions.IMPORTANCE Heterocyst-forming cyanobacteria have the ability to perform oxygenic photosynthesis and to assimilate atmospheric CO2 and N2 These organisms grow as filaments that fix these gases specifically in vegetative cells and heterocysts, respectively. For the filaments to grow, these types of cells exchange nutrients, including sucrose, which serves as a source of reducing power and of carbon skeletons for the heterocysts. Movement of sucrose between cells in the filament takes place through septal junctions and has been traced with a fluorescent sucrose analog, esculin, that can be taken up by the cells. Here, we identified α-glucoside transporters of Anabaena that mediate uptake of esculin and, notably, influence septal structure and the function of septal junctions.
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50
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Antimicrobial peptide cWFW kills by combining lipid phase separation with autolysis. Sci Rep 2017; 7:44332. [PMID: 28276520 PMCID: PMC5343580 DOI: 10.1038/srep44332] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 02/07/2017] [Indexed: 12/17/2022] Open
Abstract
The synthetic cyclic hexapeptide cWFW (cyclo(RRRWFW)) has a rapid bactericidal activity against both Gram-positive and Gram-negative bacteria. Its detailed mode of action has, however, remained elusive. In contrast to most antimicrobial peptides, cWFW neither permeabilizes the membrane nor translocates to the cytoplasm. Using a combination of proteome analysis, fluorescence microscopy, and membrane analysis we show that cWFW instead triggers a rapid reduction of membrane fluidity both in live Bacillus subtilis cells and in model membranes. This immediate activity is accompanied by formation of distinct membrane domains which differ in local membrane fluidity, and which severely disrupts membrane protein organisation by segregating peripheral and integral proteins into domains of different rigidity. These major membrane disturbances cause specific inhibition of cell wall synthesis, and trigger autolysis. This novel antibacterial mode of action holds a low risk to induce bacterial resistance, and provides valuable information for the design of new synthetic antimicrobial peptides.
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