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Del Duca S, Riccardi C, Vassallo A, Fontana G, Castronovo LM, Chioccioli S, Fani R. The Histidine Biosynthetic Genes in the Superphylum Bacteroidota-Rhodothermota-Balneolota-Chlorobiota: Insights into the Evolution of Gene Structure and Organization. Microorganisms 2021; 9:microorganisms9071439. [PMID: 34361875 PMCID: PMC8305728 DOI: 10.3390/microorganisms9071439] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 06/23/2021] [Accepted: 06/29/2021] [Indexed: 12/02/2022] Open
Abstract
One of the most studied metabolic routes is the biosynthesis of histidine, especially in enterobacteria where a single compact operon composed of eight adjacent genes encodes the complete set of biosynthetic enzymes. It is still not clear how his genes were organized in the genome of the last universal common ancestor community. The aim of this work was to analyze the structure, organization, phylogenetic distribution, and degree of horizontal gene transfer (HGT) of his genes in the Bacteroidota-Rhodothermota-Balneolota-Chlorobiota superphylum, a group of phylogenetically close bacteria with different surviving strategies. The analysis of the large variety of his gene structures and organizations revealed different scenarios with genes organized in more or less compact—heterogeneous or homogeneous—operons, in suboperons, or in regulons. The organization of his genes in the extant members of the superphylum suggests that in the common ancestor of this group, genes were scattered throughout the chromosome and that different forces have driven the assembly of his genes in compact operons. Gene fusion events and/or paralog formation, HGT of single genes or entire operons between strains of the same or different taxonomic groups, and other molecular rearrangements shaped the his gene structure in this superphylum.
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Chiu SF, Teng KW, Wang PC, Chung HY, Wang CJ, Cheng HC, Kao MC. Helicobacter pylori GmhB enzyme involved in ADP-heptose biosynthesis pathway is essential for lipopolysaccharide biosynthesis and bacterial virulence. Virulence 2021; 12:1610-1628. [PMID: 34125649 PMCID: PMC8204981 DOI: 10.1080/21505594.2021.1938449] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Helicobacter pylori infection is linked to serious gastric-related diseases including gastric cancer. However, current therapies for treating H. pylori infection are challenged by the increased antibiotic resistance of H. pylori. Therefore, it is in an urgent need to identify novel targets for drug development against H. pylori infection. In this study, HP0860 gene from H. pylori predicted to encode a D-glycero-D-manno-heptose-1,7-bisphosphate phosphatase (GmhB) involved in the synthesis of ADP-L-glycero-D-manno-heptose for the assembly of lipopolysaccharide (LPS) in the inner core region was cloned and characterized. We reported HP0860 protein is monomeric and functions as a phosphatase by converting D-glycero-D-manno-heptose-1,7-bisphosphate into D-glycero-D-manno-heptose-1-phosphate with a preference for the β-anomer over the α-anomer of sugar phosphate substrates. Subsequently, a HP0860 knockout mutant and its complementary mutant were constructed and their phenotypic properties were examined. HP0860 knockout mutant contained both mature and immature forms of LPS and could still induce significant IL-8 secretion after gastric AGS cell infection, suggesting other enzymatic activities in HP0860 knockout mutant might be able to partially compensate for the loss of HP0860 activity. In addition, HP0860 knockout mutant was much more sensitive to antibiotic novobiocin, had decreased adherence abilities, and caused less classic hummingbird phenotype on the infected AGS cells, indicating H. pylori lacking HP0860 is less virulent. Furthermore, the disruption of HP0860 gene altered the sorting of cargo proteins into outer membrane vesicles (OMVs). The above findings confirm the importance of HP0860 in LPS core biosynthesis and shed light on therapeutic intervention against H. pylori infection.
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Affiliation(s)
- Sue-Fen Chiu
- Institute of Molecular Medicine, College of Life Science, National Tsing Hua University, Hsinchu, Taiwan
| | - Kai-Wen Teng
- Institute of Molecular Medicine, College of Life Science, National Tsing Hua University, Hsinchu, Taiwan
| | - Po-Chuan Wang
- Department of Gastroenterology, Hsinchu MacKay Memorial Hospital, Hsinchu, Taiwan
| | - Hsin-Yu Chung
- Institute of Molecular Medicine, College of Life Science, National Tsing Hua University, Hsinchu, Taiwan
| | - Chun-Jen Wang
- Institute of Molecular Medicine, College of Life Science, National Tsing Hua University, Hsinchu, Taiwan
| | - Hui-Chun Cheng
- Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, Hsinchu, Taiwan.,Department of Life Science, College of Life Science, National Tsing Hua University, Hsinchu, Taiwan
| | - Mou-Chieh Kao
- Institute of Molecular Medicine, College of Life Science, National Tsing Hua University, Hsinchu, Taiwan.,Department of Life Science, College of Life Science, National Tsing Hua University, Hsinchu, Taiwan
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García-Weber D, Arrieumerlou C. ADP-heptose: a bacterial PAMP detected by the host sensor ALPK1. Cell Mol Life Sci 2021; 78:17-29. [PMID: 32591860 PMCID: PMC11072087 DOI: 10.1007/s00018-020-03577-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 06/12/2020] [Accepted: 06/15/2020] [Indexed: 01/16/2023]
Abstract
The innate immune response constitutes the first line of defense against pathogens. It involves the recognition of pathogen-associated molecular patterns (PAMPs) by pathogen recognition receptors (PRRs), the production of inflammatory cytokines and the recruitment of immune cells to infection sites. Recently, ADP-heptose, a soluble intermediate of the lipopolysaccharide biosynthetic pathway in Gram-negative bacteria, has been identified by several research groups as a PAMP. Here, we recapitulate the evidence that led to this identification and discuss the controversy over the immunogenic properties of heptose 1,7-bisphosphate (HBP), another bacterial heptose previously defined as an activator of innate immunity. Then, we describe the mechanism of ADP-heptose sensing by alpha-protein kinase 1 (ALPK1) and its downstream signaling pathway that involves the proteins TIFA and TRAF6 and induces the activation of NF-κB and the secretion of inflammatory cytokines. Finally, we discuss possible delivery mechanisms of ADP-heptose in cells during infection, and propose new lines of thinking to further explore the roles of the ADP-heptose/ALPK1/TIFA axis in infections and its potential implication in the control of intestinal homeostasis.
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Affiliation(s)
- Diego García-Weber
- INSERM, U1016, Institut Cochin, CNRS, UMR8104, Université de Paris, 22 rue Méchain, 75014, Paris, France
| | - Cécile Arrieumerlou
- INSERM, U1016, Institut Cochin, CNRS, UMR8104, Université de Paris, 22 rue Méchain, 75014, Paris, France.
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Synthesis and Evaluation of Mannitol-Based Inhibitors for Lipopolysaccharide Biosynthesis. INTERNATIONAL JOURNAL OF MEDICINAL CHEMISTRY 2016; 2016:3475235. [PMID: 26981280 PMCID: PMC4766332 DOI: 10.1155/2016/3475235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 01/06/2016] [Accepted: 01/17/2016] [Indexed: 11/20/2022]
Abstract
Antibiotic resistance is a serious threat against humankind and the need for new therapeutics is crucial. Without working antibiotics, diseases that we thought were extinct will come back. In this paper two new mannitol bisphosphate analogs, 1,6-dideoxy-1,6-diphosphoramidate mannitol and 1,6-dideoxy-1,6-dimethansulfonamide mannitol, have been synthesized and evaluated as potential inhibitors of the enzyme GmhB in the biosynthesis of lipopolysaccharides. 1,6-Dideoxy-1,6-diphosphoramidate mannitol showed promising result in computational docking experiments, but neither phosphate analog showed activity in the Kirby-Bauer antibiotic susceptibility test.
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Determinants of intrinsic aminoglycoside resistance in Pseudomonas aeruginosa. Antimicrob Agents Chemother 2012; 56:5591-602. [PMID: 22908149 DOI: 10.1128/aac.01446-12] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Screening of a transposon insertion mutant library of Pseudomonas aeruginosa for increased susceptibility to paromomycin identified a number of genes whose disruption enhanced susceptibility of this organism to multiple aminoglycosides, including tobramycin, amikacin, and gentamicin. These included genes associated with lipid biosynthesis or metabolism (lptA, faoA), phosphate uptake (pstB), and two-component regulators (amgRS, PA2797-PA2798) and a gene of unknown function (PA0392). Deletion mutants lacking these showed enhanced panaminoglycoside susceptibility that was reversed by the cloned genes, confirming their contribution to intrinsic panaminoglycoside resistance. None of these mutants showed increased aminoglycoside permeation of the cell envelope, indicating that increased susceptibility was not related to enhanced aminoglycoside uptake owing to a reduced envelope barrier function. Several mutants (pstB, faoA, PA0392, amgR) did, however, show increased cytoplasmic membrane depolarization relative to wild type following gentamicin exposure, consistent with the membranes of these mutants being more prone to perturbation, likely by gentamicin-generated mistranslated polypeptides. Mutants lacking any two of these resistance genes in various combinations invariably showed increased aminoglycoside susceptibility relative to single-deletion mutants, confirming their independent contribution to resistance and highlighting the complexity of the intrinsic aminoglycoside resistome in P. aeruginosa. Deletion of these genes also compromised the high-level panaminoglycoside resistance of clinical isolates, emphasizing their important contribution to acquired resistance.
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Taylor PL, Sugiman-Marangos S, Zhang K, Valvano MA, Wright GD, Junop MS. Structural and kinetic characterization of the LPS biosynthetic enzyme D-alpha,beta-D-heptose-1,7-bisphosphate phosphatase (GmhB) from Escherichia coli. Biochemistry 2010; 49:1033-41. [PMID: 20050699 DOI: 10.1021/bi901780j] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lipopolysaccharide is a major component of the outer membrane of gram-negative bacteria and provides a permeability barrier to many commonly used antibiotics. ADP-heptose residues are an integral part of the LPS inner core, and mutants deficient in heptose biosynthesis demonstrate increased membrane permeability. The heptose biosynthesis pathway involves phosphorylation and dephosphorylation steps not found in other pathways for the synthesis of nucleotide sugar precursors. Consequently, the heptose biosynthetic pathway has been marked as a novel target for antibiotic adjuvants, which are compounds that facilitate and potentiate antibiotic activity. D-alpha,beta-D-heptose-1,7-bisphosphate phosphatase (GmhB) catalyzes the third essential step of LPS heptose biosynthesis. This study describes the first crystal structure of GmhB and enzymatic analysis of the protein. Structure-guided mutations followed by steady state kinetic analysis, together with established precedent for HAD phosphatases, suggest that GmhB functions through a phosphoaspartate intermediate. This study provides insight into the structure-function relationship of GmhB, a new target for combatting gram-negative bacterial infection.
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Affiliation(s)
- Patricia L Taylor
- Department of Biochemistry and Biomedical Sciences and M. G. DeGroote Institute for Infectious Disease Research, McMaster University, 1200 Main Street West, Hamilton, Ontario L8N 3Z5, Canada
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O'Dwyer CA, Li MS, Langford PR, Kroll JS. Meningococcal biofilm growth on an abiotic surface - a model for epithelial colonization? MICROBIOLOGY-SGM 2009; 155:1940-1952. [PMID: 19383679 DOI: 10.1099/mic.0.026559-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Neisseria meningitidis colonizes the human nasopharynx asymptomatically, often for prolonged periods, but occasionally invades from this site to cause life-threatening infection. In the nasopharynx aggregated organisms are closely attached to the epithelial surface, in a state in which the expression of components of the bacterial envelope differs significantly from that found in organisms multiplying exponentially in liquid phase culture or in the blood. We and others have hypothesized that here they are in the biofilm state, and to explore this we have investigated biofilm formation by the serogroup B strain MC58 on an abiotic surface, in a sorbarod system. Transcriptional changes were analysed, focusing on alteration in gene expression relevant to polysaccharide capsulation, lipooligosaccharide and outer-membrane protein synthesis - all phenotypes of importance in epithelial colonization. We report downregulation of genes controlling capsulation and the production of core oligosaccharide, and upregulation of genes encoding a range of outer-membrane components, reflecting phenotypic changes that have been established to occur in the colonizing state. A limited comparison with organisms recovered from an extended period of co-cultivation with epithelial cells suggests that this model system may better mirror natural colonization than do short-term meningococcal/epithelial cell co-cultivation systems. Modelling prolonged meningococcal colonization with a sorbarod system offers insight into gene expression during this important, but experimentally relatively inaccessible, phase of human infection.
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Affiliation(s)
- Clíona A O'Dwyer
- Molecular Infectious Diseases Group, Department of Paediatrics, Faculty of Medicine, Imperial College London, Wright-Fleming Institute, St Mary's Hospital Campus, Norfolk Place, London W2 1PG, UK
| | - Ming-Shi Li
- Molecular Infectious Diseases Group, Department of Paediatrics, Faculty of Medicine, Imperial College London, Wright-Fleming Institute, St Mary's Hospital Campus, Norfolk Place, London W2 1PG, UK
| | - Paul R Langford
- Molecular Infectious Diseases Group, Department of Paediatrics, Faculty of Medicine, Imperial College London, Wright-Fleming Institute, St Mary's Hospital Campus, Norfolk Place, London W2 1PG, UK
| | - J Simon Kroll
- Molecular Infectious Diseases Group, Department of Paediatrics, Faculty of Medicine, Imperial College London, Wright-Fleming Institute, St Mary's Hospital Campus, Norfolk Place, London W2 1PG, UK
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Zughaier SM, Lindner B, Howe J, Garidel P, Koch MHJ, Brandenburg K, Stephens DS. Physicochemical characterization and biological activity of lipooligosaccharides and lipid A from Neisseria meningitidis. ACTA ACUST UNITED AC 2008; 13:343-57. [PMID: 18182462 DOI: 10.1177/0968051907084435] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Meningococcal endotoxin is the major contributor to the pathogenesis of fulminant sepsis and meningitis of meningococcal disease and is a potent activator of the MyD88-dependent and MyD88-independent pathways via the MD-2/TLR4 receptor. To understand better the biological properties of meningococcal endotoxin that initiates these events, the physicochemical structure of Neisseria meningitidis lipopoly(oligo)saccharide (LOS) of the serogroup B wild-type strain NMB (NeuNAc-Gal beta-GlcNAc-Gal beta-Glc beta-Hep2(GlcNAc,Glc alpha)PEA-Kdo2-lipid A, 1,4'-bisphosphorylated +/- PEA, PEtN) and the genetically-defined mutants (gmhB, Kdo2 -lipid A; kdtA, meningococcal lipid A; gmhB-lpxL1, Kdo2penta-acylated lipid A and NMB-lpx1, penta-acylated meningococcal LOS) were assessed in relation to bioactivity. Confirming previous work, Kdo2lipid A was the minimal structure required for optimal activation of the MD-2/TLR4 pathway of human macrophages. Meningococcal lipid A alone was a very weak agonist in stimulating human macrophages, even at high doses. Penta-acylated LOS structures demonstrated a moderate reduction in TLR4/MyD88-dependent signaling and a dramatic decrease in TLR4-TRIF-dependent signaling. For a better understanding of these results, we have performed an analysis of physicochemical parameters of the LOS structures such as the gel-to-liquid crystalline phase transition of the acyl chains, the inclination angle of the diglucosamine backbone with respect to the membrane surface, and the aggregate structure, and have found a very significant correlation of these parameters with biological activities extending our concept of endotoxicity.
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Affiliation(s)
- Susu M Zughaier
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia 30033, USA.
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Zughaier S, Steeghs L, van der Ley P, Stephens DS. TLR4-dependent adjuvant activity of Neisseria meningitidis lipid A. Vaccine 2007; 25:4401-9. [PMID: 17466419 PMCID: PMC2722072 DOI: 10.1016/j.vaccine.2007.03.029] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2006] [Revised: 03/07/2007] [Accepted: 03/14/2007] [Indexed: 10/23/2022]
Abstract
The adjuvant activity of Neisseria meningitidis serogroup B lipopoly(oligo)saccharide (LOS) from wild-type and genetically defined LOS mutants and unglycosylated meningococcal lipid A was assessed in C3H/HeN and C3H/HeJ mice. Meningococcal lipid A, a weak agonist for TLR4/MD-2 in human macrophages, was found to have adjuvant activity similar to that of wild-type and KDO(2)-lipid A LOS in C3H/HeN mice. All meningococcal LOS structures as adjuvants induced high titers of IgG1, IgG2a and IgG2b but very little IgG3 to OMP compared to no adjuvant PBS controls. In addition, induced OMP antibodies were shown to have high bactericidal activity against serogroup B meningococci. Purified LOS and lipid A structures failed to induce any adjuvant activity in C3H/HeJ mice indicating that meningococcal LOS as an adjuvant was TLR4-dependent. Unglycosylated meningococcal lipid A because of its weak agonist activity for human macrophages and retention of adjuvant activity may be a candidate for use in serogroup B meningococcal OMP and OMV vaccines and for use as an adjuvant in other vaccines.
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Affiliation(s)
- Susu Zughaier
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Liana Steeghs
- Department of Infectious Diseases and Immunology, Utrecht University, Utrecht, The Netherlands
| | - Peter van der Ley
- Department of Research and Development, Netherlands Vaccine Institute, The Netherlands
| | - David S. Stephens
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
- Laboratories of Microbial Pathogenesis,, Department of Veterans Affairs Medical Center, Atlanta, GA, USA
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Plant L, Sundqvist J, Zughaier S, Lövkvist L, Stephens DS, Jonsson AB. Lipooligosaccharide structure contributes to multiple steps in the virulence of Neisseria meningitidis. Infect Immun 2006; 74:1360-7. [PMID: 16428785 PMCID: PMC1360357 DOI: 10.1128/iai.74.2.1360-1367.2006] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lipooligosaccharide (LOS) of Neisseria meningitidis has been implicated in meningococcal interaction with host epithelial cells and is a major factor contributing to the human proinflammatory response to meningococci. LOS mutants of the encapsulated N. meningitidis serogroup B strain NMB were used to further determine the importance of the LOS structure in in vitro adherence and invasion of human pharyngeal epithelial cells by meningococci and to study pathogenicity in a mouse (CD46 transgenic) model of meningococcal disease. The wild-type strain [NeuNAc-Galbeta-GlcNAc-Galbeta-Glcbeta-Hep2 (GlcNAc, Glcalpha) 3-deoxy-D-manno-2-octulosonic acid (KDO2)-lipid A; 1,4' bisphosphorylated], although poorly adherent, rapidly invaded an epithelial cell layer in vitro, survived and multiplied early in blood, reached the cerebrospinal fluid, and caused lethal disease in the mouse model. In contrast, the Hep2 (GlcNAc) KDO2-lipid A (pgm) mutant, which was highly adherent to cultured epithelial cells, caused significantly less bacteremia and mortality in the mouse model. The Hep2-KDO2-lipid A (rfaK) mutant was shown to be moderately adherent and to cause levels of bacteremia and mortality similar to those caused by the wild-type strain in the mouse model. The KDO2-lipid A (gmhB) mutant, which lacks the heptose disaccharide in the inner core of LOS, avidly attached to epithelial cells but was otherwise avirulent. Disease development correlated with expression of specific LOS structures and was associated with lower adherence but rapid meningococcal passage to and survival in the bloodstream, induction of proinflammatory cytokines, and the crossing of the blood-brain barrier. Taken together, the results of this study further define the importance of the LOS structure as a virulence component involved in multiple steps in the pathogenesis of N. meningitidis.
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Affiliation(s)
- Laura Plant
- Department of Medical Biochemistry and Microbiology, Biomedical Centrum, Uppsala University, PO Box 582, Uppsala, Sweden.
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Kahler CM, Datta A, Tzeng YL, Carlson RW, Stephens DS. Inner core assembly and structure of the lipooligosaccharide of Neisseria meningitidis: capacity of strain NMB to express all known immunotype epitopes. Glycobiology 2004; 15:409-19. [PMID: 15574803 DOI: 10.1093/glycob/cwi018] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Neisseria meningitidis expresses a heterogeneous population of lipooligosaccharide (LOS) inner cores variously substituted with alpha1-3-linked glucose and O-3, O-6, and O-7 linked phosphoethanolamine (PEA), as well as glycine, attached to HepII. Combinations of these attachments to the LOS inner core represent immunodominant epitopes that are being exploited as future vaccine candidates. Historically, each LOS immunotype was structurally assessed and prescribed a certain unique inner core epitope. We report that a single isolate, strain NMB, possesses the capacity to produce all of the known neisserial LOS inner core immunotype structures. Analysis of the inner cores from parental LOS revealed the presence or absence of alpha1,3-linked glucose, O-6 and/or O-7 linked PEA, in addition to glycine attached at the 7 position of the HepII inner core. Identification and inactivation of lpt-6 in strain NMB resulted in the loss of both O-6 and O-7 linked PEA groups from the LOS inner core, suggesting that Lpt-6 of strain NMB may have bifunctional transferase activities or that the O-6 linked PEA groups once attached to the inner core undergo nonenzymatic transfer to the O-7 position of HepII. Although O-3 linked PEA was not detected in parental LOS inner cores devoid of alpha1-3-linked glucose residues, LOS glycoforms bearing O-3 PEA groups accumulated in a truncated mutant, NMBlgtK (Hep2Kdo2-lipid A). Because these structures disappeared upon inactivation of the lpt-3 locus, strain NMB expresses a functional O-3 PEA transferase. The LOS glycoforms expressed by NMBlgtK were also devoid of glycine attachments, indicating that glycine was added to the inner core after the completion of the gamma-chain by LgtK. In conclusion, strain NMB has the capability to express all known inner core structures, but in in vitro culture L2 and L4 immunotype structures are predominantly expressed.
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Affiliation(s)
- Charlene M Kahler
- Department of Microbiology, Monash University, Clayton 3800, Australia.
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Wright JC, Hood DW, Randle GA, Makepeace K, Cox AD, Li J, Chalmers R, Richards JC, Moxon ER. lpt6, a gene required for addition of phosphoethanolamine to inner-core lipopolysaccharide of Neisseria meningitidis and Haemophilus influenzae. J Bacteriol 2004; 186:6970-82. [PMID: 15466050 PMCID: PMC522187 DOI: 10.1128/jb.186.20.6970-6982.2004] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We previously described a gene, lpt3, required for the addition of phosphoethanolamine (PEtn) at the 3 position on the beta-chain heptose (HepII) of the inner-core Neisseria meningitidis lipopolysaccharide (LPS), but it has long been recognized that the inner-core LPS of some strains possesses PEtn at the 6 position (PEtn-6) on HepII. We have now identified a gene, lpt6 (NMA0408), that is required for the addition of PEtn-6 on HepII. The lpt6 gene is located in a region previously identified as Lgt-3 and is associated with other LPS biosynthetic genes. We screened 113 strains, representing all serogroups and including disease and carriage strains, for the lpt3 and lpt6 genes and showed that 36% contained both genes, while 50% possessed lpt3 only and 12% possessed lpt6 only. The translated amino acid sequence of lpt6 has a homologue (72.5% similarity) in a product of the Haemophilus influenzae Rd genome sequence. Previous structural studies have shown that all H. influenzae strains investigated have PEtn-6 on HepII. Consistent with this, we found that, among 70 strains representing all capsular serotypes and nonencapsulated H. influenzae strains, the lpt6 homologue was invariably present. Structural analysis of LPS from H. influenzae and N. meningitidis strains where lpt6 had been insertionally inactivated revealed that PEtn-6 on HepII could not be detected. The translated amino acid sequences from the N. meningitidis and H. influenzae lpt6 genes have conserved residues across their lengths and are part of a family of proven or putative PEtn transferases present in a wide range of gram-negative bacteria.
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Affiliation(s)
- J Claire Wright
- Molecular Infectious Diseases Group, Dept. of Pediatrics, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford OX3 9DS, United Kingdom.
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Zughaier SM, Tzeng YL, Zimmer SM, Datta A, Carlson RW, Stephens DS. Neisseria meningitidis lipooligosaccharide structure-dependent activation of the macrophage CD14/Toll-like receptor 4 pathway. Infect Immun 2004; 72:371-80. [PMID: 14688118 PMCID: PMC343956 DOI: 10.1128/iai.72.1.371-380.2004] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Meningococcal lipopoly(oligo)saccharide (LOS) is a major inflammatory mediator of fulminant meningococcal sepsis and meningitis. Highly purified wild-type meningococcal LOS and LOS from genetically defined mutants of Neisseria meningitidis that contained specific mutations in LOS biosynthesis pathways were used to confirm that meningococcal LOS activation of macrophages was CD14/Toll-like receptor 4 (TLR4)-MD-2 dependent and to elucidate the LOS structural requirement for TLR4 activation. Expression of TLR4 but not TLR2 was required, and antibodies to both TLR4 and CD14 blocked meningococcal LOS activation of macrophages. Meningococcal LOS alpha or beta chain oligosaccharide structure did not influence CD14/TLR4-MD-2 activation. However, meningococcal lipid A, expressed by meningococci with defects in 3-deoxy-D-manno-octulosonic acid (KDO) biosynthesis or transfer, resulted in an approximately 10-fold (P < 0.0001) reduction in biologic activity compared to KDO2-containing meningococcal LOS. Removal of KDO2 from LOS by acid hydrolysis also dramatically attenuated cellular responses. Competitive inhibition assays showed similar binding of glycosylated and unglycosylated lipid A to CD14/TLR4-MD-2. A decrease in the number of lipid A phosphate head groups or penta-acylated meningococcal LOS modestly attenuated biologic activity. Meningococcal endotoxin is a potent agonist of the macrophage CD14/TLR4-MD-2 receptor, helping explain the fulminant presentation of meningococcal sepsis and meningitis. KDO2 linked to meningococcal lipid A was structurally required for maximal activation of the human macrophage TLR4 pathway and indicates an important role for KDO-lipid A in endotoxin biologic activity.
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Affiliation(s)
- Susu M Zughaier
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
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Tzeng YL, Datta A, Strole C, Kolli VSK, Birck MR, Taylor WP, Carlson RW, Woodard RW, Stephens DS. KpsF is the arabinose-5-phosphate isomerase required for 3-deoxy-D-manno-octulosonic acid biosynthesis and for both lipooligosaccharide assembly and capsular polysaccharide expression in Neisseria meningitidis. J Biol Chem 2002; 277:24103-13. [PMID: 11956197 DOI: 10.1074/jbc.m200931200] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have identified and defined the function of kpsF of Neisseria meningitidis and the homologues of kpsF in encapsulated K1 and K5 Escherichia coli. KpsF was shown to be the arabinose-5-phosphate isomerase, an enzyme not previously identified in prokaryotes, that mediates the interconversion of ribulose 5-phosphate and arabinose 5-phosphate. KpsF is required for 3-deoxy-d-manno-octulosonic acid (Kdo) biosynthesis in N. meningitidis. Mutation of kpsF or the gene encoding the CMP-Kdo synthetase (kpsU/kdsB) in N. meningitidis resulted in expression of a lipooligosaccharide (LOS) structure that contained only lipid A and reduced capsule expression in the five invasive disease-associated meningococcal serogroups (A, B, C, Y, and W-135). The step linking meningococcal capsule and LOS biosynthesis was shown to be Kdo production as the expression of capsule was wild type in a Kdo transferase (kdtA) mutant. Thus, in addition to lipooligosaccharide assembly, Kdo is required for meningococcal capsular polysaccharide expression. Furthermore, N. meningitidis, unlike enteric Gram-negative bacteria, can survive and synthesize only unglycosylated lipid A.
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Affiliation(s)
- Yih-Ling Tzeng
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, the Department of Veterans Affairs Medical Center, Atlanta, Georgia 30033, USA
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Valvano MA, Messner P, Kosma P. Novel pathways for biosynthesis of nucleotide-activated glycero-manno-heptose precursors of bacterial glycoproteins and cell surface polysaccharides. MICROBIOLOGY (READING, ENGLAND) 2002; 148:1979-1989. [PMID: 12101286 DOI: 10.1099/00221287-148-7-1979] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Miguel A Valvano
- Department of Microbiology and Immunology and Medicine, University of Western Ontario, London, Ontario, N6A 5C1, Canada1
| | - Paul Messner
- Zentrum für Ultrastrukturforschung und Ludwig Boltzmann-Institut für Molekulare Nanotechnologie, Universität für Bodenkultur Wien, A-1180 Wien, Austria2
| | - Paul Kosma
- Institut für Chemie, Universität für Bodenkultur Wien, A-1190 Wien, Austria3
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Tzeng YL, Datta A, Kolli VK, Carlson RW, Stephens DS. Endotoxin of Neisseria meningitidis composed only of intact lipid A: inactivation of the meningococcal 3-deoxy-D-manno-octulosonic acid transferase. J Bacteriol 2002; 184:2379-88. [PMID: 11948150 PMCID: PMC134985 DOI: 10.1128/jb.184.9.2379-2388.2002] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lipopolysaccharide, lipooligosaccharide (LOS), or endotoxin is important in bacterial survival and the pathogenesis of gram-negative bacteria. A necessary step in endotoxin biosynthesis is 3-deoxy-D-manno-octulosonic acid (Kdo) glycosylation of lipid A, catalyzed by the Kdo transferase KdtA (WaaA). In enteric gram-negative bacteria, this step is essential for survival. A nonpolar kdtA::aphA-3 mutation was created in Neisseria meningitidis via allelic exchange, and the mutant was viable. Detailed structural analysis demonstrated that the endotoxin of the kdtA::aphA-3 mutant was composed of fully acylated lipid A with variable phosphorylation but without Kdo glycosylation. In contrast to what happens in other gram-negative bacteria, tetra-acylated lipid IV(A) did not accumulate. The LOS structure of the kdtA::aphA-3 mutant was restored to the wild-type structure by complementation with kdtA from N. meningitidis or Escherichia coli. The expression of a fully acylated, unglycosylated lipid A indicates that lipid A biosynthesis in N. meningitidis can proceed without the addition of Kdo and that KdtA is not essential for survival of the meningococcus.
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Affiliation(s)
- Yih-Ling Tzeng
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30303, USA
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Kneidinger B, Marolda C, Graninger M, Zamyatina A, McArthur F, Kosma P, Valvano MA, Messner P. Biosynthesis pathway of ADP-L-glycero-beta-D-manno-heptose in Escherichia coli. J Bacteriol 2002; 184:363-9. [PMID: 11751812 PMCID: PMC139585 DOI: 10.1128/jb.184.2.363-369.2002] [Citation(s) in RCA: 140] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The steps involved in the biosynthesis of the ADP-L-glycero-beta-D-manno-heptose (ADP-L-beta-D-heptose) precursor of the inner core lipopolysaccharide (LPS) have not been completely elucidated. In this work, we have purified the enzymes involved in catalyzing the intermediate steps leading to the synthesis of ADP-D-beta-D-heptose and have biochemically characterized the reaction products by high-performance anion-exchange chromatography. We have also constructed a deletion in a novel gene, gmhB (formerly yaeD), which results in the formation of an altered LPS core. This mutation confirms that the GmhB protein is required for the formation of ADP-D-beta-D-heptose. Our results demonstrate that the synthesis of ADP-D-beta-D-heptose in Escherichia coli requires three proteins, GmhA (sedoheptulose 7-phosphate isomerase), HldE (bifunctional D-beta-D-heptose 7-phosphate kinase/D-beta-D-heptose 1-phosphate adenylyltransferase), and GmhB (D,D-heptose 1,7-bisphosphate phosphatase), as well as ATP and the ketose phosphate precursor sedoheptulose 7-phosphate. A previously characterized epimerase, formerly named WaaD (RfaD) and now renamed HldD, completes the pathway to form the ADP-L-beta-D-heptose precursor utilized in the assembly of inner core LPS.
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Affiliation(s)
- Bernd Kneidinger
- Zentrum für Ultrastrukturforschung und Ludwig Boltzmann-Institut für Molekulare Nanotechnologie, A-1180 Vienna, Austria
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