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Bose P, Jaiswal MK, Singh SK, Singh RK, Tiwari VK. Growing impact of sialic acid-containing glycans in future drug discovery. Carbohydr Res 2023; 527:108804. [PMID: 37031650 DOI: 10.1016/j.carres.2023.108804] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/21/2023] [Accepted: 03/29/2023] [Indexed: 04/05/2023]
Abstract
In nature, almost all cells are covered with a complex array of glycan chain namely sialic acids or nuraminic acids, a negatively charged nine carbon sugars which is considered for their great therapeutic importance since long back. Owing to its presence at the terminal end of lipid bilayer (commonly known as terminal sugars), the well-defined sialosides or sialoconjugates have served pivotal role on the cell surfaces and thus, the sialic acid-containing glycans can modulate and mediate a number of imperative cellular interactions. Understanding of the sialo-protein interaction and their roles in vertebrates in regard of normal physiology, pathological variance, and evolution has indeed a noteworthy journey in medicine. In this tutorial review, we present a concise overview about the structure, linkages in chemical diversity, biological significance followed by chemical and enzymatic modification/synthesis of sialic acid containing glycans. A more focus is attempted about the recent advances, opportunity, and more over growing impact of sialosides and sialoconjugates in future drug discovery and development.
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Sialic acid and biology of life: An introduction. SIALIC ACIDS AND SIALOGLYCOCONJUGATES IN THE BIOLOGY OF LIFE, HEALTH AND DISEASE 2020. [PMCID: PMC7153325 DOI: 10.1016/b978-0-12-816126-5.00001-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Sialic acids are important molecule with high structural diversity. They are known to occur in higher animals such as Echinoderms, Hemichordata, Cephalochorda, and Vertebrata and also in other animals such as Platyhelminthes, Cephalopoda, and Crustaceae. Plants are known to lack sialic acid. But they are reported to occur in viruses, bacteria, protozoa, and fungi. Deaminated neuraminic acid although occurs in vertebrates and bacteria, is reported to occur in abundance in the lower vertebrates. Sialic acids are mostly located in terminal ends of glycoproteins and glycolipids, capsular and tissue polysialic acids, bacterial lipooligosaccharides/polysaccharides, and in different forms that dictate their role in biology. Sialic acid play important roles in human physiology of cell-cell interaction, communication, cell-cell signaling, carbohydrate-protein interactions, cellular aggregation, development processes, immune reactions, reproduction, and in neurobiology and human diseases in enabling the infection process by bacteria and virus, tumor growth and metastasis, microbiome biology, and pathology. It enables molecular mimicry in pathogens that allows them to escape host immune responses. Recently sialic acid has found role in therapeutics. In this chapter we have highlighted the (i) diversity of sialic acid, (ii) their occurrence in the diverse life forms, (iii) sialylation and disease, and (iv) sialic acid and therapeutics.
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Aziz A, Sarovich DS, Nosworthy E, Beissbarth J, Chang AB, Smith-Vaughan H, Price EP, Harris TM. Molecular Signatures of Non-typeable Haemophilus influenzae Lung Adaptation in Pediatric Chronic Lung Disease. Front Microbiol 2019; 10:1622. [PMID: 31379777 PMCID: PMC6646836 DOI: 10.3389/fmicb.2019.01622] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 07/01/2019] [Indexed: 12/03/2022] Open
Abstract
Non-typeable Haemophilus influenzae (NTHi), an opportunistic pathogen of the upper airways of healthy children, can infect the lower airways, driving chronic lung disease. However, the molecular basis underpinning NTHi transition from a commensal to a pathogen is not clearly understood. Here, we performed comparative genomic and transcriptomic analyses of 12 paired, isogenic NTHi strains, isolated from the nasopharynx (NP) and bronchoalveolar lavage (BAL) of 11 children with chronic lung disease, to identify convergent molecular signatures associated with lung adaptation. Comparative genomic analyses of the 12 NP-BAL pairs demonstrated that five were genetically identical, with the remaining seven differing by only 1 to 3 mutations. Within-patient transcriptomic analyses identified between 2 and 58 differentially expressed genes in 8 of the 12 NP-BAL pairs, including pairs with no observable genomic changes. Whilst no convergence was observed at the gene level, functional enrichment analysis revealed significant under-representation of differentially expressed genes belonging to Coenzyme metabolism, Function unknown, Translation, ribosomal structure, and biogenesis Cluster of Orthologous Groups categories. In contrast, Carbohydrate transport and metabolism, Cell motility and secretion, Intracellular trafficking and secretion, and Energy production categories were over-represented. This observed trend amongst genetically unrelated NTHi strains provides evidence of convergent transcriptional adaptation of NTHi to pediatric airways that deserves further exploration. Understanding the pathoadaptative mechanisms that NTHi employs to infect and persist in the lower pediatric airways is essential for devising targeted diagnostics and treatments aimed at minimizing disease severity, and ultimately, preventing NTHi lung infections and subsequent chronic lung disease in children.
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Affiliation(s)
- Ammar Aziz
- Child Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
| | - Derek S. Sarovich
- Child Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
- GeneCology Research Centre, University of the Sunshine Coast, Sippy Downs, QLD, Australia
| | - Elizabeth Nosworthy
- Child Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
| | - Jemima Beissbarth
- Child Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
| | - Anne B. Chang
- Child Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
- Department of Respiratory and Sleep Medicine, Children’s Health Queensland, Queensland University of Technology, Brisbane, QLD, Australia
| | - Heidi Smith-Vaughan
- Child Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
| | - Erin P. Price
- Child Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
- GeneCology Research Centre, University of the Sunshine Coast, Sippy Downs, QLD, Australia
| | - Tegan M. Harris
- Child Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
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Nontypeable Haemophilus influenzae Has Evolved Preferential Use of N-Acetylneuraminic Acid as a Host Adaptation. mBio 2019; 10:mBio.00422-19. [PMID: 31064827 PMCID: PMC6509186 DOI: 10.1128/mbio.00422-19] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Host-adapted bacterial pathogens such as NTHi cannot survive out of their host environment and have evolved host-specific mechanisms to obtain nutrients and evade the immune response. Relatively few of these host adaptations have been characterized at the molecular level. NTHi utilizes sialic acid as a nutrient and also incorporates this sugar into LOS, which is important in biofilm formation and immune evasion. In the present study, we showed that NTHi has evolved to preferentially utilize the Neu5Ac form of sialic acid. This adaptation is due to the substrate preference of the enzyme CMP-Neu5Ac synthetase, which synthesizes the activated form of Neu5Ac for macromolecule biosynthesis. This adaptation allows NTHi to evade killing by a human antibody response against the nonhuman sialic acid Neu5Gc. Nontypeable Haemophilus influenzae (NTHi) is a Gram-negative bacterial pathogen that is adapted exclusively to human hosts. NTHi utilizes sialic acid from the host as a carbon source and as a terminal sugar on the outer membrane glycolipid lipooligosaccharide (LOS). Sialic acid expressed on LOS is critical in NTHi biofilm formation and immune evasion. There are two major forms of sialic acids in most mammals, N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc), the latter of which is derived from Neu5Ac. Humans lack the enzyme to convert Neu5Ac to Neu5Gc and do not express Neu5Gc in normal tissues; instead, Neu5Gc is recognized as a foreign antigen. A recent study showed that dietary Neu5Gc can be acquired by NTHi colonizing humans and then presented on LOS, which acts as an antigen for the initial induction of anti-Neu5Gc antibodies. Here we examined Neu5Gc uptake and presentation on NTHi LOS. We show that, although Neu5Gc and Neu5Ac are utilized equally well as sole carbon sources, Neu5Gc is not incorporated efficiently into LOS. When equal amounts of Neu5Gc and Neu5Ac are provided in culture media, there is ∼4-fold more Neu5Ac incorporated into LOS, suggesting a bias in a step of the LOS biosynthetic pathway. CMP-Neu5Ac synthetase (SiaB) was shown to have ∼4,000-fold-higher catalytic efficiency for Neu5Ac than for Neu5Gc. These data suggest that NTHi has adapted preferential utilization of Neu5Ac, thus avoiding presentation of the nonhuman Neu5Gc in the bacterial cell surface. The selective pressure for this adaptation may represent the human antibody response to the Neu5Gc xenoantigen.
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Wang H, Liu L, Cao Q, Mao W, Zhang Y, Qu X, Cai X, Lv Y, Chen H, Xu X, Wang X. Haemophilus parasuis α-2,3-sialyltransferase-mediated lipooligosaccharide sialylation contributes to bacterial pathogenicity. Virulence 2019; 9:1247-1262. [PMID: 30036124 PMCID: PMC6104685 DOI: 10.1080/21505594.2018.1502606] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Bacterial lipooligosaccharide (LOS) is an important virulence-associated factor, and its sialylation largely confers its ability to mediate cell adhesion, invasion, inflammation, and immune evasion. Here, we investigated the function of the Haemophilus parasuis α-2,3-sialyltransferase gene, lsgB, which determines the terminal sialylation of LOS, by generating a lsgB deletion mutant as well as a complementation strain. Our data indicate a direct effect of lsgB on LOS sialylation and reveal important roles of lsgB in promoting the pathogenicity of H. parasuis, including adhesion to and invasion of porcine cells in vitro, bacterial load and survival in vivo, as well as a contribution to serum resistance. These observations highlight the function of lsgB in mediating LOS sialylation and more importantly its role in H. parasuis infection. These findings provide a more profound understanding of the pathogenic mechanism of this disease-causing bacterium.
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Affiliation(s)
- Huan Wang
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , China
| | - Lu Liu
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , China
| | - Qi Cao
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , China
| | - Weiting Mao
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , China
| | - Yage Zhang
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , China
| | - Xinyi Qu
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , China
| | - Xuwang Cai
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , China.,c Key Laboratory of Development of Veterinary Diagnostic Products , Ministry of Agriculture of the People's Republic of China , Wuhan , China
| | - Yujin Lv
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , China.,d College of Veterinary Medicine , Henan University of Animal Husbandry and Economy , Zhengzhou , China
| | - Huanchun Chen
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , China.,c Key Laboratory of Development of Veterinary Diagnostic Products , Ministry of Agriculture of the People's Republic of China , Wuhan , China
| | - Xiaojuan Xu
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , China.,c Key Laboratory of Development of Veterinary Diagnostic Products , Ministry of Agriculture of the People's Republic of China , Wuhan , China
| | - Xiangru Wang
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , China.,c Key Laboratory of Development of Veterinary Diagnostic Products , Ministry of Agriculture of the People's Republic of China , Wuhan , China
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Gangi Setty T, Mowers JC, Hobbs AG, Maiya SP, Syed S, Munson RS, Apicella MA, Subramanian R. Molecular characterization of the interaction of sialic acid with the periplasmic binding protein from Haemophilus ducreyi. J Biol Chem 2018; 293:20073-20084. [PMID: 30315109 DOI: 10.1074/jbc.ra118.005151] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 10/11/2018] [Indexed: 12/18/2022] Open
Abstract
The primary role of bacterial periplasmic binding proteins is sequestration of essential metabolites present at a low concentration in the periplasm and making them available for active transporters that transfer these ligands into the bacterial cell. The periplasmic binding proteins (SiaPs) from the tripartite ATP-independent periplasmic (TRAP) transport system that transports mammalian host-derived sialic acids have been well studied from different pathogenic bacteria, including Haemophilus influenzae, Fusobacterium nucleatum, Pasteurella multocida, and Vibrio cholerae SiaPs bind the sialic acid N-acetylneuraminic acid (Neu5Ac) with nanomolar affinity by forming electrostatic and hydrogen-bonding interactions. Here, we report the crystal structure of a periplasmic binding protein (SatA) of the ATP-binding cassette (ABC) transport system from the pathogenic bacterium Haemophilus ducreyi The structure of Hd-SatA in the native form and sialic acid-bound forms (with Neu5Ac and N-glycolylneuraminic acid (Neu5Gc)), determined to 2.2, 1.5, and 2.5 Å resolutions, respectively, revealed a ligand-binding site that is very different from those of the SiaPs of the TRAP transport system. A structural comparison along with thermodynamic studies suggested that similar affinities are achieved in the two classes of proteins through distinct mechanisms, one enthalpically driven and the other entropically driven. In summary, our structural and thermodynamic characterization of Hd-SatA reveals that it binds sialic acids with nanomolar affinity and that this binding is an entropically driven process. This information is important for future structure-based drug design against this pathogen and related bacteria.
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Affiliation(s)
- Thanuja Gangi Setty
- From the Institute for Stem Cell Biology and Regenerative Medicine, GKVK Post, Bangalore 560065, India,; the University of Trans-Disciplinary Health Sciences and Technology (TDU), Bengaluru, Karnataka 560064, India
| | - Jonathan C Mowers
- the Departments of Biochemistry and Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Aaron G Hobbs
- the Departments of Biochemistry and Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Shubha P Maiya
- From the Institute for Stem Cell Biology and Regenerative Medicine, GKVK Post, Bangalore 560065, India
| | - Sanaa Syed
- From the Institute for Stem Cell Biology and Regenerative Medicine, GKVK Post, Bangalore 560065, India
| | - Robert S Munson
- the Center for Microbial Interface Biology, Ohio State University, Columbus, Ohio 43210, and
| | - Michael A Apicella
- Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Ramaswamy Subramanian
- From the Institute for Stem Cell Biology and Regenerative Medicine, GKVK Post, Bangalore 560065, India,; the Departments of Biochemistry and Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242.
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7
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Nontypeable Haemophilus influenzae Lipooligosaccharide Expresses a Terminal Ketodeoxyoctanoate In Vivo, Which Can Be Used as a Target for Bactericidal Antibody. mBio 2018; 9:mBio.01401-18. [PMID: 30065093 PMCID: PMC6069110 DOI: 10.1128/mbio.01401-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHi) is an important pathogen in individuals of all ages. The lipooligosaccharide (LOS) of NTHi has evolved a complex structure that can be attributed to a multiplicity of glycosyltransferases, the random switching of glycosyltransferase gene expression via phase variation, and the complex structure of its core region with multiple glycoform branch points. This article adds to that complexity by describing a multifunctional enzyme (LsgB) which optimally functions when the species is grown on a solid surface and which can add either a ketodeoxyoctanoate (KDO) or an N-acetylneuramic acid (Neu5Ac) moiety to a terminal N-acetyllactosamine structure of LOS. Our studies show that expression of lsgB is reduced four- to sixfold when NTHi is grown in broth. The substrate that the enzyme utilizes is dependent upon the concentration of free Neu5Ac (between 1 and 10 µg/ml) in the environment. In environments in which Neu5Ac is below that level, the enzyme utilizes endogenous CMP-KDO as the substrate. Our studies show that during in vivo growth in an NTHi biofilm, the KDO moiety is expressed by the organism. Monoclonal antibody 6E4, which binds KDO, is bactericidal for NTHi strains that express the KDO epitope at high levels. In a survey of 33 NTHi strains isolated from healthy and diseased individuals, the antibody was bactericidal (>90% kill) for 12 strains (36%). These studies open up the possibility of using a KDO-based glycoconjugate vaccine as part of a multicomponent vaccine against NTHi.IMPORTANCE Nontypeable Haemophilus influenzae is an important pathogen in middle ear infections in children, sinusitis in adults, and acute bronchitis in individuals with chronic obstructive lung disease. The organism is very well adapted to the human host environment, and this has hindered successful development of an effective vaccine. In this article, we describe a mechanism by which the bacteria decorates its surface lipooligosaccharide with a sugar unique to Gram-negative bacteria, ketodeoxyoctanoate (KDO). This sugar decoration is present during active infection and we have shown that an antibody directed against this sugar can result in killing of the organism. These data demonstrate that the lipooligosaccharide ketodeoxyoctanoate epitope may be a novel NTHi-specific candidate vaccine antigen.
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Post DMB, Ketterer MR, Coffin JE, Reinders LM, Munson RS, Bair T, Murphy TF, Foster ED, Gibson BW, Apicella MA. Comparative Analyses of the Lipooligosaccharides from Nontypeable Haemophilus influenzae and Haemophilus haemolyticus Show Differences in Sialic Acid and Phosphorylcholine Modifications. Infect Immun 2016; 84:765-74. [PMID: 26729761 PMCID: PMC4771351 DOI: 10.1128/iai.01185-15] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 12/28/2015] [Indexed: 11/20/2022] Open
Abstract
Haemophilus haemolyticus and nontypeable Haemophilus influenzae (NTHi) are closely related upper airway commensal bacteria that are difficult to distinguish phenotypically. NTHi causes upper and lower airway tract infections in individuals with compromised airways, while H. haemolyticus rarely causes such infections. The lipooligosaccharide (LOS) is an outer membrane component of both species and plays a role in NTHi pathogenesis. In this study, comparative analyses of the LOS structures and corresponding biosynthesis genes were performed. Mass spectrometric and immunochemical analyses showed that NTHi LOS contained terminal sialic acid more frequently and to a higher extent than H. haemolyticus LOS did. Genomic analyses of 10 strains demonstrated that H. haemolyticus lacked the sialyltransferase genes lic3A and lic3B (9/10) and siaA (10/10), but all strains contained the sialic acid uptake genes siaP and siaT (10/10). However, isothermal titration calorimetry analyses of SiaP from two H. haemolyticus strains showed a 3.4- to 7.3-fold lower affinity for sialic acid compared to that of NTHi SiaP. Additionally, mass spectrometric and immunochemical analyses showed that the LOS from H. haemolyticus contained phosphorylcholine (ChoP) less frequently than the LOS from NTHi strains. These differences observed in the levels of sialic acid and ChoP incorporation in the LOS structures from H. haemolyticus and NTHi may explain some of the differences in their propensities to cause disease.
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Affiliation(s)
| | | | - Jeremy E Coffin
- Department of Microbiology, The University of Iowa, Iowa City, Iowa, USA
| | | | - Robert S Munson
- The Center for Microbial Pathogenesis at the Research Institute at Nationwide Children's Hospital and the Center for Microbial Interface Biology and Department of Pediatrics, The Ohio State University, Columbus, Ohio, USA
| | - Thomas Bair
- Bioinformatics Facility, The University of Iowa, Iowa City, Iowa, USA
| | - Timothy F Murphy
- Department of Medicine, University at Buffalo, State University of New York, Buffalo, New York, USA
| | - Eric D Foster
- Department of Biostatistics, College of Public Health, The University of Iowa, Iowa City, Iowa, USA
| | - Bradford W Gibson
- Buck Institute for Research on Aging, Novato, California, USA Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA
| | - Michael A Apicella
- Department of Microbiology, The University of Iowa, Iowa City, Iowa, USA
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9
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Lichtenegger S, Bina I, Roier S, Bauernfeind S, Keidel K, Schild S, Anthony M, Reidl J. Characterization of lactate utilization and its implication on the physiology of Haemophilus influenzae. Int J Med Microbiol 2014; 304:490-8. [PMID: 24674911 PMCID: PMC4012139 DOI: 10.1016/j.ijmm.2014.02.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 02/10/2014] [Accepted: 02/20/2014] [Indexed: 01/03/2023] Open
Abstract
Haemophilus influenzae is a Gram-negative bacillus and a frequent commensal of the human nasopharynx. Earlier work demonstrated that in H. influenzae type b, l-lactate metabolism is associated with serum resistance and in vivo survival of the organism. To further gain insight into lactate utilization of the non-typeable (NTHi) isolate 2019 and laboratory prototype strain Rd KW20, deletion mutants of the l-lactate dehydrogenase (lctD) and permease (lctP) were generated and characterized. It is shown, that the apparent KM of l-lactate uptake is 20.1 μM as determined for strain Rd KW20. Comparison of the COPD isolate NTHi 2019-R with the corresponding lctP knockout strain for survival in human serum revealed no lactate dependent serum resistance. In contrast, we observed a 4-fold attenuation of the mutant strain in a murine model of nasopharyngeal colonization. Characterization of lctP transcriptional control shows that the lactate utilization system in H. influenzae is not an inductor inducible system. Rather negative feedback regulation was observed in the presence of l-lactate and this is dependent on the ArcAB regulatory system. Additionally, for 2019 it was found that lactate may have signaling function leading to increased cell growth in late log phase under conditions where no l-lactate is metabolized. This effect seems to be ArcA independent and was not observed in strain Rd KW20. We conclude that l-lactate is an important carbon-source and may act as host specific signal substrate which fine tunes the globally acting ArcAB regulon and may additionally affect a yet unknown signaling system and thus may contribute to enhanced in vivo survival.
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Affiliation(s)
- Sabine Lichtenegger
- Institute of Molecular Biosciences, University of Graz, Humboldtstr. 50, 8010 Graz, Austria
| | - Isabelle Bina
- Institute of Molecular Biosciences, University of Graz, Humboldtstr. 50, 8010 Graz, Austria
| | - Sandro Roier
- Institute of Molecular Biosciences, University of Graz, Humboldtstr. 50, 8010 Graz, Austria
| | - Stilla Bauernfeind
- Insitute of Hygiene and Microbiology, University of Wuerzburg, Josef-Schneider Str. 2 E1, Wuerzburg 97080, Germany
| | - Kristina Keidel
- Insitute of Hygiene and Microbiology, University of Wuerzburg, Josef-Schneider Str. 2 E1, Wuerzburg 97080, Germany
| | - Stefan Schild
- Institute of Molecular Biosciences, University of Graz, Humboldtstr. 50, 8010 Graz, Austria
| | - Mark Anthony
- Department of Paediatrics, Oxford University Hospitals, Headington, Oxford OX3 9DU, United Kingdom
| | - Joachim Reidl
- Institute of Molecular Biosciences, University of Graz, Humboldtstr. 50, 8010 Graz, Austria.
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Relative contributions of lipooligosaccharide inner and outer core modifications to nontypeable Haemophilus influenzae pathogenesis. Infect Immun 2013; 81:4100-11. [PMID: 23980106 DOI: 10.1128/iai.00492-13] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Nontypeable Haemophilus influenzae (NTHi) is a frequent commensal of the human nasopharynx that causes opportunistic infection in immunocompromised individuals. Existing evidence associates lipooligosaccharide (LOS) with disease, but the specific and relative contributions of NTHi LOS modifications to virulence properties of the bacterium have not been comprehensively addressed. Using NTHi strain 375, an isolate for which the detailed LOS structure has been determined, we compared systematically a set of isogenic mutant strains expressing sequentially truncated LOS. The relative contributions of 2-keto-3-deoxyoctulosonic acid, the triheptose inner core, oligosaccharide extensions on heptoses I and III, phosphorylcholine, digalactose, and sialic acid to NTHi resistance to antimicrobial peptides (AMP), self-aggregation, biofilm formation, cultured human respiratory epithelial infection, and murine pulmonary infection were assessed. We show that opsX, lgtF, lpsA, lic1, and lic2A contribute to bacterial resistance to AMP; lic1 is related to NTHi self-aggregation; lgtF, lic1, and siaB are involved in biofilm growth; opsX and lgtF participate in epithelial infection; and opsX, lgtF, and lpsA contribute to lung infection. Depending on the phenotype, the involvement of these LOS modifications occurs at different extents, independently or having an additive effect in combination. We discuss the relative contribution of LOS epitopes to NTHi virulence and frame a range of pathogenic traits in the context of infection.
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11
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Clark SE, Eichelberger KR, Weiser JN. Evasion of killing by human antibody and complement through multiple variations in the surface oligosaccharide of Haemophilus influenzae. Mol Microbiol 2013; 88:603-18. [PMID: 23577840 DOI: 10.1111/mmi.12214] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2013] [Indexed: 11/29/2022]
Abstract
The lipopolysaccharide (LPS) of H. influenzae is highly variable. Much of the structural diversity is derived from phase variation, or high frequency on-off switching, of molecules attached during LPS biosynthesis. In this study, we examined the dynamics of LPS phase variation following exposure to human serum as a source of antibody and complement in multiple H. influenzae isolates. We show that lic2A, lgtC and lex2A switch from phase-off to phase-on following serial passage in human serum. These genes, which control attachment of a galα1-4gal di-galactoside structure (lic2A and lgtC phase-on) or an alternative glucose extension (lex2A phase-on) from the same hexose moiety, reduce binding of bactericidal antibody to conserved inner core LPS structures. The effects of the di-galactoside and alternative glucose extension were also examined in the context of the additional LPS phase variable structures phosphorylcholine (ChoP) and sialic acid. We found that di-galactoside, the alternative glucose extension, ChoP, and sialic acid each contribute independently to bacterial survival in the presence of human complement, and have an additive effect in combination. We propose that LPS phase variable extensions serve to shield conserved inner core structures from recognition by host immune components encountered during infection.
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Affiliation(s)
- Sarah E Clark
- Department of Microbiology, University of Pennsylvania, Philadelphia, PA, USA
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Loss-of-function mutation in bi-functional marine bacterial sialyltransferase. Biosci Biotechnol Biochem 2012; 76:1639-44. [PMID: 22972324 DOI: 10.1271/bbb.120133] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
An α2,3-sialyltransferase produced by Photobacterium phosphoreum JT-ISH-467 is a bi-functional enzyme showing both α2,3-sialyltransferase and α2,3-linkage specific sialidase activity. To date, the crystal structures of several sialyltransferases have been solved, but the roles of amino acid residues around the catalytic site have not been completely clarified. Hence we performed a mutational study using α2,3-sialyltransferase cloned from P. phosphoreum JT-ISH-467 as a model enzyme to study the role of the amino acid residues around the substrate-binding site. It was found that a mutation of the glutamic acid at position 342 in the sialyltransferase resulted in a loss of sialidase activity, although the mutant showed no decrease in sialyltransferase activity. Based on this result, it is strongly expected that the Glu342 of the enzyme is an important amino acid residue for sialidase activity.
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13
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Martínez-Moliner V, Soler-Llorens P, Moleres J, Garmendia J, Aragon V. Distribution of genes involved in sialic acid utilization in strains of Haemophilus parasuis. MICROBIOLOGY-SGM 2012; 158:2117-2124. [PMID: 22609756 DOI: 10.1099/mic.0.056994-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Haemophilus parasuis is a porcine respiratory pathogen, well known as the aetiological agent of Glässer's disease. H. parasuis comprises strains of different virulence, but the virulence factors of this bacterium are not well defined. A neuraminidase activity has been previously detected in H. parasuis, but the role of sialylation in the virulence of this bacterium has not been studied. To explore the relationship between sialic acid (Neu5Ac) and virulence, we assessed the distribution of genes involved in sialic acid metabolism in 21 H. parasuis strains from different clinical origins (including nasal and systemic isolates). The neuraminidase gene nanH, together with CMP-Neu5Ac synthetase and sialyltransferase genes neuA, siaB and lsgB, were included in the study. Neuraminidase activity was found to be common in H. parasuis isolates, and the nanH gene from 12 isolates was expressed in Escherichia coli and further characterized. Sequence analysis showed that the NanH predicted protein contained the motifs characteristic of the catalytic site of sialidases. While an association between the presence of nanH and the different origins of the strains was not detected, the lsgB gene was predominantly present in the systemic isolates, and was not amplified from any of the nasal isolates tested. Analysis of the lipooligosaccharide (LOS) from reference strains Nagasaki (virulent, lsgB(+)) and SW114 (non-virulent, lsgB(-)) showed the presence of sialic acid in the LOS from the Nagasaki strain, supporting the role of sialylation in the virulence of this bacterial pathogen. Further studies are needed to clarify the role of sialic acid in the pathogenicity of H. parasuis.
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Affiliation(s)
- Verónica Martínez-Moliner
- Centre de Recerca en Sanitat Animal (CReSA), UAB-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
| | - Pedro Soler-Llorens
- Departamento de Microbiología y Parasitología, Universidad de Navarra, Pamplona, Spain
| | - Javier Moleres
- Instituto de Agrobiotecnología UPNA-CSIC-Gobierno Navarra, Mutilva, Spain
| | - Junkal Garmendia
- Instituto de Agrobiotecnología UPNA-CSIC-Gobierno Navarra, Mutilva, Spain
| | - Virginia Aragon
- Institut de Recerca i Tecnologia Agroalimentàries (IRTA), Barcelona, Spain.,Centre de Recerca en Sanitat Animal (CReSA), UAB-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
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Kreisman LS, Cobb BA. Infection, inflammation and host carbohydrates: a Glyco-Evasion Hypothesis. Glycobiology 2012; 22:1019-30. [PMID: 22492234 DOI: 10.1093/glycob/cws070] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Microbial immune evasion can be achieved through the expression, or mimicry, of host-like carbohydrates on the microbial cell surface to hide from detection. However, disparate reports collectively suggest that evasion could also be accomplished through the modulation of the host glycosylation pathways, a mechanism that we call the "Glyco-Evasion Hypothesis". Here, we will summarize the evidence in support of this paradigm by reviewing three separate bodies of work present in the literature. We review how infection and inflammation can lead to host glycosylation changes, how host glycosylation changes can increase susceptibility to infection and inflammation and how glycosylation impacts molecular and cellular function. Then, using these data as a foundation, we propose a unifying hypothesis in which microbial products can hijack host glycosylation to manipulate the immune response to the advantage of the pathogen. This model reveals areas of research that we believe could significantly improve our fight against infectious disease.
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Affiliation(s)
- Lori Sc Kreisman
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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15
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Apicella MA. Nontypeable Haemophilus influenzae: the role of N-acetyl-5-neuraminic acid in biology. Front Cell Infect Microbiol 2012; 2:19. [PMID: 22919611 PMCID: PMC3417534 DOI: 10.3389/fcimb.2012.00019] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 02/07/2012] [Indexed: 11/13/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHi) is an exclusive human pathogen, which has evolved a number of unique mechanisms to survive within the human environment. An important part of this is the ability of the organism to take up and incorporate sialic acid into its surface structures. This protects the organism against host adaptive and innate immune factor as well as serving as a mechanism for sustaining itself within biofilms. Recent evidence suggests that this also may be the source of the evolution of human antibodies to non-human sialic acid structures, which can lead to inflammation in the host. In very rare instances, evolution of antibodies to sialylated lipooligosaccharide (LOS) mimics of human antigens can result in autoimmune disease.
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Affiliation(s)
- Michael A Apicella
- Departments of Microbiology and Internal Medicine, The Carver College of Medicine, The University of Iowa, Iowa City IA, USA.
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16
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Identification and characterization of a lipopolysaccharide α,2,3-sialyltransferase from the human pathogen Helicobacter bizzozeronii. J Bacteriol 2012; 194:2540-50. [PMID: 22408169 DOI: 10.1128/jb.00126-12] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Terminal sialic acid in the lipopolysaccharides (LPSs) of mucosal pathogens is an important virulence factor. Here we report the characterization of a Helicobacter sialyltransferase involved in the biosynthesis of sialylated LPS in Helicobacter bizzozeronii, the only non-pylori gastric Helicobacter species isolated from humans thus far. Starting from the genome sequences of canine and human strains, we identified potential sialyltransferases downstream of three genes involved in the biosynthesis of N-acetylneuraminic acid. One of these candidates showed monofunctional α,2,3-sialyltransferase activity with a preference for N-acetyllactosamine as a substrate. The LPSs from different strains were shown by SDS-PAGE and high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) to contain sialic acid after neuraminidase treatment. The expression of this sialyltransferase and sialyl-LPS appeared to be a phase-variable characteristic common to both human and canine H. bizzozeronii strains. The sialylation site of the LPSs of two H. bizzozeronii strains was determined to be NeuAc-Hex-HexNAc, suggesting terminal 3'-sialyl-LacNAc. Moreover, serological typing revealed the possible presence of sialyl-Lewis X in two additional strains, indicating that H. bizzozeronii could also mimic the surface glycans of mammalian cells. The expression of sialyl-glycans may influence the adaptation process of H. bizzozeronii during the host jump from dogs to humans.
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Stafford G, Roy S, Honma K, Sharma A. Sialic acid, periodontal pathogens and Tannerella forsythia: stick around and enjoy the feast! Mol Oral Microbiol 2012; 27:11-22. [PMID: 22230462 PMCID: PMC4049603 DOI: 10.1111/j.2041-1014.2011.00630.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Periodontal pathogens, like any other human commensal or pathogenic bacterium, must possess both the ability to acquire the necessary growth factors and the means to adhere to surfaces or reside and survive in their environmental niche. Recent evidence has suggested that sialic acid containing host molecules may provide both of these requirements in vivo for several periodontal pathogens but most notably for the red complex organism Tannerella forsythia. Several other periodontal pathogens also possess sialic acid scavenging enzymes - sialidases, which can also expose adhesive epitopes, but might also act as adhesins in their own right. In addition, recent experimental work coupled with the release of several genome sequences has revealed that periodontal bacteria have a range of sialic acid uptake and utilization systems while others may also use sialic acid as a cloaking device on their surface to mimic host and avoid immune recognition. This review will focus on these systems in a range of periodontal bacteria with a focus on Ta. forsythia.
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Affiliation(s)
- G Stafford
- Oral and Maxillofacial Pathology, School of Clinical Dentistry, University of Sheffield, Sheffield, UK.
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18
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Inactivation of Haemophilus influenzae lipopolysaccharide biosynthesis genes interferes with outer membrane localization of the hap autotransporter. J Bacteriol 2012; 194:1815-22. [PMID: 22287523 DOI: 10.1128/jb.06316-11] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nontypeable Haemophilus influenzae is a major cause of localized respiratory tract disease and initiates infection by colonizing the nasopharynx. Colonization requires adherence to host epithelial cells, which is mediated by surface proteins such as the Hap adhesin. In this study, we identified a relationship between Hap levels in the outer membrane and lipopolysaccharide (LPS) biosynthesis enzymes. We found that mutation of the rfaF, pgmB, lgtC, kfiC, orfE, rfbP, lsgB, or lsgD genes, which are involved in the synthesis of the LPS oligosaccharide core in H. influenzae strain Rd/HapS243A, resulted in loss of Hap in the bacterial outer membrane and a decrease in hap transcript levels. In contrast, the same mutations had no effect on outer membrane localization of H. influenzae P5 or IgA1 protease or levels of p5 or iga1 transcripts, suggesting a Hap-specific effect. Elimination of the HtrA periplasmic protease resulted in a return of Hap to the outer membrane and restoration of hap transcript levels. Consistently, in lgtC phase-off bacteria, Hap was absent from the outer membrane, and hap transcript levels were reduced. Hap localization and hap transcript levels were not related to LPS size but to the functions of the LPS biosynthesis enzymes themselves. We speculate that the lack of certain LPS biosynthesis enzymes causes Hap to mislocalize and accumulate in the periplasm, where it is degraded by HtrA. This degradation then leads to a decrease in hap transcript levels. Together, these data highlight a novel interplay between Hap and LPS biosynthesis that can influence H. influenzae interactions with the host.
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Howard MD, Willis L, Wakarchuk W, St. Michael F, Cox A, Horne WT, Hontecillas R, Bassaganya-Riera J, Lorenz E, Inzana TJ. Genetics and molecular specificity of sialylation of Histophilus somni lipooligosaccharide (LOS) and the effect of LOS sialylation on Toll-like receptor-4 signaling. Vet Microbiol 2011; 153:163-72. [DOI: 10.1016/j.vetmic.2011.02.054] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Revised: 02/23/2011] [Accepted: 02/28/2011] [Indexed: 01/15/2023]
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20
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Thon V, Lau K, Yu H, Tran BK, Chen X. PmST2: a novel Pasteurella multocida glycolipid α2-3-sialyltransferase. Glycobiology 2011; 21:1206-16. [PMID: 21515586 DOI: 10.1093/glycob/cwr054] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Pasteurella multocida (Pm) is a multi-species pathogen that causes diseases in animals and humans. Sialyltransferase activity has been detected in multiple Pm strains and sialylation has been shown to be important for the pathogenesis of Pm. Three putative sialyltransferase genes have been identified in Pm genomic strain Pm70. We have reported previously that a Pm0188 gene homolog in Pm strain P-1059 (ATCC 15742) encodes a multifunctional sialyltransferase (PmST1). We demonstrate here that while PmST1 prefers to use oligosaccharides as acceptors, PmST2 encoded by the Pm0508 gene homolog in the same Pm strain is a novel glycolipid α2-3-sialyltransferase that prefers to use lactosyl lipids as acceptor substrates. PmST2 and PmST1 thus complement each other for an efficient synthesis of α2-3-linked sialosides with or without lipid portion. In addition, β1-4-linked galactosyl lipids are better PmST2 substrates than β1-3-linked galactosyl lipids. PmST2 has been used successfully in the preparative scale synthesis of sialyllactosyl sphingosine (lyso-GM3), which is an important glycolipid and an intermediate for synthesizing more complex glycolipids such as gangliosides.
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Affiliation(s)
- Vireak Thon
- Department of Chemistry, University of California, Davis, CA 95616, USA
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21
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Hallström T, Riesbeck K. Haemophilus influenzae and the complement system. Trends Microbiol 2010; 18:258-65. [PMID: 20399102 DOI: 10.1016/j.tim.2010.03.007] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Revised: 03/10/2010] [Accepted: 03/17/2010] [Indexed: 02/04/2023]
Abstract
The respiratory tract pathogen Haemophilus influenzae is responsible for a variety of infections in humans including septicemia, bronchitis, pneumonia, and acute otitis media. The pathogenesis of H. influenzae relies on its capacity to resist human host defenses including the complement system, and thus H. influenzae has developed several efficient strategies to circumvent complement attack. In addition to attracting specific host complement regulators directly to the bacterial surface, the capsule, lipooligosaccharides, and several outer membrane proteins contribute to resistance against complement-mediated attacks and hence increased bacterial survival. Insights into the mechanisms of complement evasion by H. influenzae are important for understanding pathogenesis and for developing vaccines and new therapies aimed at patients with, for example, chronic obstructive pulmonary disease. Here we overview current knowledge on the different mechanisms by which H. influenzae evades attack by the host complement system.
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Affiliation(s)
- Teresia Hallström
- Medical Microbiology, Department of Laboratory Medicine Malmö, Lund University, Skåne University Hospital, SE-205 02 Malmö, Sweden
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22
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Yamamoto T. Marine bacterial sialyltransferases. Mar Drugs 2010; 8:2781-94. [PMID: 21139844 PMCID: PMC2996176 DOI: 10.3390/md8112781] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 10/25/2010] [Accepted: 11/02/2010] [Indexed: 01/04/2023] Open
Abstract
Sialyltransferases transfer N-acetylneuraminic acid (Neu5Ac) from the common donor substrate of these enzymes, cytidine 5′-monophospho-N-acetylneuraminic acid (CMP-Neu5Ac), to acceptor substrates. The enzymatic reaction products including sialyl-glycoproteins, sialyl-glycolipids and sialyl-oligosaccharides are important molecules in various biological and physiological processes, such as cell-cell recognition, cancer metastasis, and virus infection. Thus, sialyltransferases are thought to be important enzymes in the field of glycobiology. To date, many sialyltransferases and the genes encoding them have been obtained from various sources including mammalian, bacterial and viral sources. During the course of our research, we have detected over 20 bacteria that produce sialyltransferases. Many of the bacteria we isolated from marine environments are classified in the genus Photobacterium or the closely related genus Vibrio. The paper reviews the sialyltransferases obtained mainly from marine bacteria.
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Affiliation(s)
- Takeshi Yamamoto
- Glycotechnology Business Unit, Japan Tobacco Inc., 700 Higashibara, Iwata, Shizuoka 438-0802, Japan.
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23
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Abstract
Sialic acids are a subset of nonulosonic acids, which are nine-carbon alpha-keto aldonic acids. Natural existing sialic acid-containing structures are presented in different sialic acid forms, various sialyl linkages, and on diverse underlying glycans. They play important roles in biological, pathological, and immunological processes. Sialobiology has been a challenging and yet attractive research area. Recent advances in chemical and chemoenzymatic synthesis, as well as large-scale E. coli cell-based production, have provided a large library of sialoside standards and derivatives in amounts sufficient for structure-activity relationship studies. Sialoglycan microarrays provide an efficient platform for quick identification of preferred ligands for sialic acid-binding proteins. Future research on sialic acid will continue to be at the interface of chemistry and biology. Research efforts not only will lead to a better understanding of the biological and pathological importance of sialic acids and their diversity but also could lead to the development of therapeutics.
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Affiliation(s)
- Xi Chen
- Department of Chemistry, University of California, Davis, California 95616, USA.
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24
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King S. Pneumococcal modification of host sugars: a major contributor to colonization of the human airway? Mol Oral Microbiol 2010; 25:15-24. [DOI: 10.1111/j.2041-1014.2009.00564.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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25
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Cipolla L, Gabrielli L, Bini D, Russo L, Shaikh N. Kdo: a critical monosaccharide for bacteria viability. Nat Prod Rep 2010; 27:1618-29. [DOI: 10.1039/c004750n] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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26
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Hankins JV, Trent MS. Secondary acylation of Vibrio cholerae lipopolysaccharide requires phosphorylation of Kdo. J Biol Chem 2009; 284:25804-12. [PMID: 19617350 DOI: 10.1074/jbc.m109.022772] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The lipopolysaccharide of Vibrio cholerae has been reported to contain a single 3-deoxy-d-manno-octulosonic acid (Kdo) residue that is phosphorylated. The phosphorylated Kdo sugar further links the hexa-acylated V. cholerae lipid A domain to the core oliogosaccharide and O-antigen. In this report, we confirm that V. cholerae possesses the enzymatic machinery to synthesize a phosphorylated Kdo residue. Further, we have determined that the presence of the phosphate group on the Kdo residue is necessary for secondary acylation in V. cholerae. The requirement for a secondary substituent on the Kdo residue (either an additional Kdo sugar or a phosphate group) was also found to be critical for secondary acylation catalyzed by LpxL proteins from Bordetella pertussis, Escherichia coli, and Haemophilus influenzae. Although three putative late acyltransferase orthologs have been identified in the V. cholerae genome (Vc0212, Vc0213, and Vc1577), only Vc0213 appears to be functional. Vc0213 functions as a myristoyl transferase acylating lipid A at the 2'-position of the glucosamine disaccharide. Generally acyl-ACPs serve as fatty acyl donors for the acyltransferases required for lipopolysaccharide biosynthesis; however, in vitro assays indicate that Vc0213 preferentially utilizes myristoyl-CoA as an acyl donor. This is the first report to biochemically characterize enzymes involved in the biosynthesis of the V. cholerae Kdo-lipid A domain.
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Affiliation(s)
- Jessica V Hankins
- Department of Molecular Biochemistry and Biochemistry, Medical College of Georgia, Augusta, Georgia 30912, USA
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27
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Sialic acid catabolism confers a competitive advantage to pathogenic vibrio cholerae in the mouse intestine. Infect Immun 2009; 77:3807-16. [PMID: 19564383 DOI: 10.1128/iai.00279-09] [Citation(s) in RCA: 143] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Sialic acids comprise a family of nine-carbon ketosugars that are ubiquitous on mammalian mucous membranes. However, sialic acids have a limited distribution among Bacteria and are confined mainly to pathogenic and commensal species. Vibrio pathogenicity island 2 (VPI-2), a 57-kb region found exclusively among pathogenic strains of Vibrio cholerae, contains a cluster of genes (nan-nag) putatively involved in the scavenging (nanH), transport (dctPQM), and catabolism (nanA, nanE, nanK, and nagA) of sialic acid. The capacity to utilize sialic acid as a carbon and energy source might confer an advantage to V. cholerae in the mucus-rich environment of the gut, where sialic acid availability is extensive. In this study, we show that V. cholerae can utilize sialic acid as a sole carbon source. We demonstrate that the genes involved in the utilization of sialic acid are located within the nan-nag region of VPI-2 by complementation of Escherichia coli mutants and gene knockouts in V. cholerae N16961. We show that nanH, dctP, nanA, and nanK are highly expressed in V. cholerae grown on sialic acid. By using the infant mouse model of infection, we show that V. cholerae DeltananA strain SAM1776 is defective in early intestinal colonization stages. In addition, SAM1776 shows a decrease in the competitive index in colonization-competition assays comparing the mutant strain with both O1 El Tor and classical strains. Our data indicate an important relationship between the catabolism of sialic acid and bacterial pathogenesis, stressing the relevance of the utilization of the resources found in the host's environment.
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28
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Crystal structure of alpha/beta-galactoside alpha2,3-sialyltransferase from a luminous marine bacterium, Photobacterium phosphoreum. FEBS Lett 2009; 583:2083-7. [PMID: 19467231 DOI: 10.1016/j.febslet.2009.05.032] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Revised: 05/12/2009] [Accepted: 05/16/2009] [Indexed: 11/21/2022]
Abstract
Alpha/beta-galactoside alpha2,3-sialyltransferase produced by Photobacterium phosphoreum JT-ISH-467 is a unique enzyme that catalyzes the transfer of N-acetylneuraminic acid residue from cytidine monophosphate N-acetylneuraminic acid to acceptor carbohydrate groups. The enzyme recognizes both mono- and di-saccharides as acceptor substrates, and can transfer Neu5Ac to both alpha-galactoside and beta-galactoside, efficiently. To elucidate the structural basis for the broad acceptor substrate specificity, we determined the crystal structure of the alpha2,3-sialyltransferase in complex with CMP. The overall structure belongs to the glycosyltransferase-B structural group. We could model a reasonable active conformation structure based on the crystal structure. The predicted structure suggested that the broad substrate specificity could be attributed to the wider entrance of the acceptor substrate binding site.
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29
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Abstract
Research into Haemophilus influenzae, a commensal and pathogen of humans, has resulted in major scientific contributions to biology. The first endonucleases (restriction enzymes), which paved the way for the new genetics, and the DNA used to obtain the first complete genome sequence of a free-living organism were obtained from H. influenzae. Prevention of invasive bacterial infections of infants, such as meningitis, has been achieved using a novel class of vaccines, of which the glycoconjugates of H. influenzae were the first to be licensed. Originally fallaciously proposed to be the aetiological agent of epidemic influenza, now known to be caused by a virus, H. influenzae is a pathogen of global public health importance. Research into the pathogenesis of the infections it causes (for example, meningitis, septicaemia, pneumonia and otitis media) are case studies in understanding the molecular basis of the variation in gene expression and gene sequences that are critical to its commensal and virulence behaviour and for the strategies that can be pursued to prevent H. influenzae diseases through vaccines.
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Affiliation(s)
- E Richard Moxon
- Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford OX3 9DS, UK
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30
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Nanoscale structural and mechanical properties of nontypeable Haemophilus influenzae biofilms. J Bacteriol 2009; 191:2512-20. [PMID: 19218382 DOI: 10.1128/jb.01596-08] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHI) bacteria are commensals in the human nasopharynx, as well as pathogens associated with a spectrum of acute and chronic infections. Two important factors that influence NTHI pathogenicity are their ability to adhere to human tissue and their ability to form biofilms. Extracellular polymeric substances (EPS) and bacterial appendages such as pili critically influence cell adhesion and intercellular cohesion during biofilm formation. Structural components in the outer cell membrane, such as lipopolysaccharides, also play a fundamental role in infection of the host organism. In spite of their importance, these pathogenic factors are not yet well characterized at the nanoscale. Here, atomic force microscopy (AFM) was used in aqueous environments to visualize structural details, including probable Hif-type pili, of live NTHI bacteria at the early stages of biofilm formation. Using single-molecule AFM-based spectroscopy, the molecular elasticities of lipooligosaccharides present on NTHI cell surfaces were analyzed and compared between two strains (PittEE and PittGG) with very different pathogenicity profiles. Furthermore, the stiffness of single cells of both strains was measured and subsequently their turgor pressure was estimated.
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31
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Schweda EKH, Twelkmeyer B, Li J. Profiling structural elements of short-chain lipopolysaccharide of non-typeable Haemophilus influenzae. Innate Immun 2009; 14:199-211. [PMID: 18669606 DOI: 10.1177/1753425908095958] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Lipopolysaccharide (LPS) is a major virulence determinant of the human bacterial pathogen Haemophilus influenzae. A characteristic feature of H. influenzae LPS is the extensive intra- and inter-strain heterogeneity of glycoform structure which is key to the role of the molecule in both commensal and disease-causing behaviour of the bacterium. The chemical composition of non-typeable Haemophilus influenzae (NTHi) LPS is highly diverse. It contains a number of different monosaccharides (Neu5Ac, L-glycero-D-manno heptose, D-glycero-D-manno heptose, Kdo, D-Glc, D-Gal, D-GlcNAc, D-GalNAc) and non-carbohydrate substituents. Prominent non-carbohydrate components are O-acetyl groups, glycine and phosphates. We now know that sialic acid (N-acetylneuraminic acid or Neu5Ac) and certain oligosaccharide extensions are important in the pathogenesis of NTHi; however, the biological implications for many of the various features are still unknown. Electrospray ionization mass spectrometry in combination with separation techniques like CE and HPLC is an indispensable tool in profiling glycoform populations in heterogeneous LPS samples. Mass spectrometry is characterized by its extreme sensitivity. Trace amounts of glycoforms expressing important virulence determinants can be detected and characterized on minute amounts of material. The present review focuses on LPS structures and mass spectrometric methods which enable us to profile these in complex mixtures.
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Affiliation(s)
- Elke K H Schweda
- Clinical Research Centre, Karolinska Institutet and University College of South Stockholm, NOVUM, Huddinge, Sweden.
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32
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Kajiwara H, Mine T, Yamamoto T. Sialyltransferases Obtained from Marine Bacteria. J Appl Glycosci (1999) 2009. [DOI: 10.5458/jag.56.77] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Masoud H, Moxon ER, Richards JC. Structural elucidation of the major Hex4 lipopolysaccharide glycoform from the lgtC mutant of Haemophilus influenzae strain Eagan. Carbohydr Res 2008; 343:1424-34. [DOI: 10.1016/j.carres.2008.04.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2007] [Revised: 02/18/2008] [Accepted: 04/01/2008] [Indexed: 10/22/2022]
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Li J, Deadman ME, Hood DW, Moxon ER, Schweda EKH. Structural Analysis of the Lipopolysaccharide from Nontypeable Haemophilus influenzae Strain R2846. Biochemistry 2008; 47:6025-38. [DOI: 10.1021/bi702510b] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jianjun Li
- Clinical Research Centre, Karolinska Institutet and University College of South Stockholm, Novum, S-14186 Huddinge, Sweden, Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario, Canada, K1A 0R6, and Molecular Infectious Diseases Group, University of Oxford, Department of Paediatrics, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DS, U.K
| | - Mary E. Deadman
- Clinical Research Centre, Karolinska Institutet and University College of South Stockholm, Novum, S-14186 Huddinge, Sweden, Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario, Canada, K1A 0R6, and Molecular Infectious Diseases Group, University of Oxford, Department of Paediatrics, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DS, U.K
| | - Derek W. Hood
- Clinical Research Centre, Karolinska Institutet and University College of South Stockholm, Novum, S-14186 Huddinge, Sweden, Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario, Canada, K1A 0R6, and Molecular Infectious Diseases Group, University of Oxford, Department of Paediatrics, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DS, U.K
| | - E. Richard Moxon
- Clinical Research Centre, Karolinska Institutet and University College of South Stockholm, Novum, S-14186 Huddinge, Sweden, Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario, Canada, K1A 0R6, and Molecular Infectious Diseases Group, University of Oxford, Department of Paediatrics, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DS, U.K
| | - Elke K. H. Schweda
- Clinical Research Centre, Karolinska Institutet and University College of South Stockholm, Novum, S-14186 Huddinge, Sweden, Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario, Canada, K1A 0R6, and Molecular Infectious Diseases Group, University of Oxford, Department of Paediatrics, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DS, U.K
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Masoud H, Moxon ER, Richards JC. Structural elucidation of lipopolysaccharide core oligosaccharides from lic1 and lic1/lic2 mutants of Haemophilus influenzae type b strain Eagan. Can J Microbiol 2008; 54:281-90. [PMID: 18389000 DOI: 10.1139/w08-009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The structures of lipopolysaccharides (LPSs) of lic1 and lic1/lic2 mutants from Haemophilus influenzae type b strain Eagan (RM153) were investigated using methylation analysis, electrospray ionization - mass spectrometry, and nuclear magnetic resonance spectroscopy on O-deacylated, O- and N-deacylated core oligosaccharide (OS); and deacylated, dephosphorylated, and terminally reduced samples. The backbone OS derived from the major LPS glycoforms were determined to consist of the inner-core triheptosyl unit, L-alpha-D-Hepp-(1-2)-L-alpha-D-Hepp-(1-3)-L-alpha-D-Hepp-(1-, common to all H. influenzae strains investigated to date that is linked to the lipid A region of the molecule via a Kdo residue to which beta-D-Glcp and beta-D-Galp residues are attached in 1,4 and 1,2 linkages to the proximal (HepI) and distal (HepIII) heptose residues, respectively. It was found that the lic1 mutant predominately elaborates the Hex4 LPS glycoforms previously identified in the parent strain where a beta-D-Glcp-(1-4)-alpha-D-Glcp unit is linked in a 1,3 linkage to the central heptose (HepII) of the triheptosyl moiety. The lic1 locus consists of 4 genes (lic1A to lic1D) in a single transcriptional unit that directs phase variable expression of phosphocholine. The lic1A gene is phased off in the RM153 isolate of strain Eagan. LPS from the double mutant, lic1/lic2 had a similar structure to that of lic1 mutant except that there was no chain extension from the central heptose in the inner core (HepII). The lic2 locus consists of 4 genes (lic2A to lic2D). Our structural data were consistent with the proposed function of lic2C, providing the first definitive evidence for its role as the glycosyltransferase required for chain initiation from HepII. The presence of an O-acetyl group at O-3 of the distal heptose (HepIII) was elucidated by 1H NMR on the mild acid liberated core OS samples.
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Affiliation(s)
- Hussein Masoud
- Institute for Biological Sciences, National Research Council of Canada, Ottawa, ON K1A0R6 Canada
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Conserved amino acid sequences in the bacterial sialyltransferases belonging to Glycosyltransferase family 80. Biochem Biophys Res Commun 2008; 365:340-3. [DOI: 10.1016/j.bbrc.2007.10.201] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Accepted: 10/31/2007] [Indexed: 11/20/2022]
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Johnston JW, Coussens NP, Allen S, Houtman JC, Turner KH, Zaleski A, Ramaswamy S, Gibson BW, Apicella MA. Characterization of the N-Acetyl-5-neuraminic Acid-binding Site of the Extracytoplasmic Solute Receptor (SiaP) of Nontypeable Haemophilus influenzae Strain 2019. J Biol Chem 2008; 283:855-65. [DOI: 10.1074/jbc.m706603200] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Johnston JW, Zaleski A, Allen S, Mootz JM, Armbruster D, Gibson BW, Apicella MA, Munson RS. Regulation of sialic acid transport and catabolism in Haemophilus influenzae. Mol Microbiol 2007; 66:26-39. [PMID: 17880422 DOI: 10.1111/j.1365-2958.2007.05890.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Virulence of nontypeable Haemophilus influenzae (NTHi) is dependent on the decoration of lipooligosaccharide with sialic acid. This sugar must be derived from the host, as NTHi cannot synthesize sialic acids. NTHi can also use sialic acid as a carbon source. The genes encoding the sialic acid transporter and the genes encoding the catabolic activities are localized to two divergently transcribed operons, the siaPT operon and the nan operon respectively. In this study, we identified SiaR as a repressor of sialic acid transport and catabolism in NTHi. Inactivation of siaR resulted in the unregulated expression of the genes in both operons. Unregulated catabolism of sialic acid in the siaR mutant resulted in the reduction of surface sialylation and an increase in serum sensitivity. In addition to SiaR-mediated repression, CRP, the cAMP receptor protein, was shown to activate expression of the siaPT operon but not the nan operon. We describe a model in which SiaR and CRP work to modulate intracellular sialic acid levels. Our results demonstrate the importance of SiaR-mediated regulation to balance the requirement of surface sialylation and the toxic accumulation of intracellular sialic acid.
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Affiliation(s)
- Jason W Johnston
- Department of Microbiology, University of Iowa, Iowa City, IA 52242, USA
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Abstract
Sialic acid occupies the terminal position within glycan molecules on the surfaces of many vertebrate cells, where it functions in diverse cellular processes such as intercellular adhesion and cell signalling. Pathogenic bacteria have evolved to use this molecule beneficially in at least two different ways: they can coat themselves in sialic acid, providing resistance to components of the host's innate immune response, or they can use it as a nutrient. Sialic acid itself is either synthesized de novo by these bacteria or scavenged directly from the host. In this mini-review we will summarize recent findings relating to sialic acid transport, modification of sialic acid by O-acetylation, and the mechanisms of sialic acid-mediated complement resistance.
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Affiliation(s)
- Emmanuele Severi
- Department of Biology (Area 10), University of York, PO Box 373, York YO10 5YW, UK
| | - Derek W Hood
- Molecular Infectious Diseases Group, University of Oxford Department of Paediatrics, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Gavin H Thomas
- Department of Biology (Area 10), University of York, PO Box 373, York YO10 5YW, UK
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Lundström SL, Twelkmeyer B, Sagemark MK, Li J, Richards JC, Hood DW, Moxon ER, Schweda EKH. Novel globoside-like oligosaccharide expression patterns in nontypeable Haemophilus influenzae lipopolysaccharide. FEBS J 2007; 274:4886-903. [PMID: 17725645 DOI: 10.1111/j.1742-4658.2007.06011.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report the novel pattern of lipopolysaccharide (LPS) expressed by two disease-associated nontypeable Haemophilus influenzae strains, 1268 and 1200. The strains express the common structural motifs of H. influenzae; globotetraose [beta-d-GalpNAc-(1-->3)-alpha-d-Galp-(1-->4)-beta-d-Galp-(1-->4)-beta-d-Glcp] and its truncated versions globoside [alpha-d-Galp-(1-->4)-beta-d-Galp-(1-->4)-beta-d-Glcp] and lactose [beta-d-Galp-(1-->4)-beta-d-Glcp] linked to the terminal heptose (HepIII) and the corresponding structures with an alpha-d-Glcp as the reducing sugar linked to the middle heptose (HepII) in the same LPS molecule. Previously these motifs had been found linked only to either the proximal heptose (HepI) or HepIII of the triheptosyl inner-core moiety l-alpha-d-Hepp-(1-->2)-[PEtn-->6]-l-alpha-d-Hepp-(1-->3)-l-alpha-d-Hepp-(1-->5)-[PPEtn-->4]-alpha-Kdo-(2-->6)-lipid A. This novel finding was obtained by structural studies of LPS using NMR techniques and ESI-MS on O-deacylated LPS and core oligosaccharide material, as well as electrospray ionization-multiple-step tandem mass spectrometry on permethylated dephosphorylated oligosaccharide material. A lpsA mutant of strain 1268 expressed LPS of reduced complexity that facilitated unambiguous structural determination. Using capillary electrophoresis-ESI-MS/MS we identified sialylated glycoforms that included sialyllactose as an extension from HepII, this is a further novel finding for H. influenzae LPS. In addition, each LPS was found to carry phosphocholine and O-linked glycine. Nontypeable H. influenzae strain 1200 expressed identical LPS structures to 1268 with the difference that strain 1200 LPS had acetates substituting HepIII, whereas strain 1268 LPS has glycine at the same position.
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Affiliation(s)
- Susanna L Lundström
- Clinical Research Centre, Karolinska Institutet and University College of South Stockholm, Huddinge, Sweden
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Ho DK, Ram S, Nelson KL, Bonthuis PJ, Smith AL. lgtC expression modulates resistance to C4b deposition on an invasive nontypeable Haemophilus influenzae. THE JOURNAL OF IMMUNOLOGY 2007; 178:1002-12. [PMID: 17202363 DOI: 10.4049/jimmunol.178.2.1002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have previously shown that C3 binding to serum-resistant nontypeable Haemophilus influenzae (NTHi) strain R2866 is slower than C3 binding to a serum-sensitive strain. Ab-dependent classical pathway activation is required for complement-dependent killing of NTHi. To further characterize the mechanism(s) of serum resistance of R2866, we compared binding of complement component C4b to R2866 with a serum-sensitive variant, R3392. We show that C4b binding to R2866 relative to R3392 was delayed, suggesting regulation of the classical pathway of complement. Increased C4b deposition on R3392 was independent of the amount and subclass of Ab binding, suggesting that an impediment to C4b binding existed on R2866. Immunoblotting and mass spectrometry indicated that lipooligosaccharide and outer membrane proteins P2 and P5 were targets for C4b. P2 and P5 sequences and expression levels were similar in both strains. Insertional inactivation of the phase-variable lipooligosaccharide biosynthesis gene lgtC in R2866 augmented C4b deposition to levels seen with R3392 and rendered the bacteria sensitive to serum and whole blood. These results suggest a direct role of lgtC expression in the inhibition of C4b deposition and consequent serum resistance of R2866. Alteration of surface glycans of NTHi may be a critical event in determining the ability of a strain to evade host defenses and cause disseminated infection.
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Affiliation(s)
- Derek K Ho
- Department of Pathobiology, School of Public Health and Community Medicine, University of Washington, Seattle, WA 98195, USA
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42
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Li J, Dzieciatkowska M, Hood DW, Cox AD, Schweda EKH, Moxon ER, Richards JC. Structural characterization of sialylated glycoforms of H. influenzae by electrospray mass spectrometry: fragmentation of protonated and sodiated O-deacylated lipopolysaccharides. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2007; 21:952-60. [PMID: 17310472 DOI: 10.1002/rcm.2916] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Sialylated lipopolysaccharide (LPS) glycoforms from Haemophilus influenzae were characterized by tandem mass spectrometry using a new generation hyphenated mass spectrometer which combines a triple quadrupole and a linear ion trap (Q-Trap). The fragmentation of both protonated and sodiated molecular ions from O-deacylated LPS (LPS-OH) obtained in MS(2) experiments in the positive mode was studied. The MS(2) spectra of protonated ions provided unambiguous evidence for the presence and sequence of sialylated lactosamine present in lacto-N-neotetraose oligosaccharide extensions but not for sialyl-lactose structures whilst fragmentation of sodiated adducts, [M+Na](+), afforded information diagnostic of mono- and disialylated lactose extensions. To study this we used a highly sialylated LPS from a H. influenzae strain capable of sialyl-lactose expression only. We then applied the method to the H. influenzae genome strain, Rd, in which glycoforms containing both sialyl-lactose and sialyl-lacto-N-neotetraose were detected from diagnostic B-ions at m/z 638.2 ([Neu5Ac(1) Hex(2)+Na](+)) and 657.2 ([Neu5Ac(1) Hex(1) HexNAc(1)+H](+)). Unique fragmentation patterns provided the locations and sequences of these oligosaccharide extensions. This is the first time both sialylated lactose and sialylated lacto-N-neotetraose units have been detected and characterized by tandem mass spectrometry in the same molecule. This methodology is of general applicability for determination of common sialylated oligosaccharide extension in bacterial LPS.
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Affiliation(s)
- Jianjun Li
- Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario, Canada, K1A 0R6.
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Li J, Richards JC. Application of capillary electrophoresis mass spectrometry to the characterization of bacterial lipopolysaccharides. MASS SPECTROMETRY REVIEWS 2007; 26:35-50. [PMID: 16967446 DOI: 10.1002/mas.20105] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Capillary electrophoresis (CE) is a high-resolution technique for the separation of complex biological mixtures and has been widely applied to biological analyses. The coupling of capillary electrophoresis with mass spectrometry (MS) provides a powerful approach for rapid identification of target analytes present at trace levels in biological matrices, and for structural characterization of complex biomolecules. Here we review the analytical potential of combined capillary electrophoresis electrospray mass spectrometry (CE-MS) for the analysis of bacterial lipopolysaccharides (LPS). This hyphened methodology facilitates the determination of closely related LPS glycoform and isoform families by exploiting differences in their unique molecular conformations and ionic charge distributions by electrophoretic separation. On-line CE-MS also provides an additional avenue to improve detection limits, which has been successfully applied to directly probe oligosaccharide LPS glycoform populations of bacteria isolated from infected animal models without the need for further passage.
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Affiliation(s)
- Jianjun Li
- Institute for Biological Sciences, National Research Council, Ottawa, ON, Canada K1A 0R6.
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Fox KL, Cox AD, Gilbert M, Wakarchuk WW, Li J, Makepeace K, Richards JC, Moxon ER, Hood DW. Identification of a bifunctional lipopolysaccharide sialyltransferase in Haemophilus influenzae: incorporation of disialic acid. J Biol Chem 2006; 281:40024-32. [PMID: 17071616 DOI: 10.1074/jbc.m602314200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The lipopolysaccharide (LPS) of non-typeable Haemophilus influenzae (NTHi) can be substituted at various positions by N-acetylneuraminic acid (Neu5Ac). LPS sialylation plays an important role in pathogenesis. The only LPS sialyltransferase characterized biochemically to date in H. influenzae is Lic3A, an alpha-2,3-sialyltransferase responsible for the addition of Neu5Ac to a lactose acceptor (Hood, D. W., Cox, A. D., Gilbert, M., Makepeace, K., Walsh, S., Deadman, M. E., Cody, A., Martin, A., Månsson, M., Schweda, E. K., Brisson, J. R., Richards, J. C., Moxon, E. R., and Wakarchuk, W. W. (2001) Mol. Microbiol. 39, 341-350). Here we describe a second sialyltransferase, Lic3B, that is a close homologue of Lic3A and present in 60% of NTHi isolates tested. A recombinant form of Lic3B was expressed in Escherichia coli and purified by affinity chromatography. We used synthetic fluorescent acceptors with a terminal lactose or sialyllactose to show that Lic3B has both alpha-2,3- and alpha-2,8-sialyltransferase activities. Structural analysis of LPS from lic3B mutant strains of NTHi confirmed that only monosialylated species were detectable, whereas disialylated species were detected upon inactivation of lic3A. Furthermore, introduction of lic3B into a lic3B-deficient strain background resulted in a significant increase in sialylation in the recipient strain. Mass spectrometric analysis of LPS indicated that glycoforms containing two Neu5Ac residues were evident that were not present in the LPS of the parent strain. These findings characterize the activity of a second sialyltransferase in H. influenzae, responsible for the addition of di-sialic acid to the LPS. Modification of the LPS by di-sialylation conferred increased resistance of the organism to the killing effects of normal human serum, as compared with mono-sialylated or non-sialylated species, indicating that this modification has biological significance.
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Affiliation(s)
- Kate L Fox
- Molecular Infectious Diseases Group, University of Oxford Department of Paediatrics, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford, OX3 9DS, United Kingdom.
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Starner TD, Zhang N, Kim G, Apicella MA, McCray PB. Haemophilus influenzae forms biofilms on airway epithelia: implications in cystic fibrosis. Am J Respir Crit Care Med 2006; 174:213-20. [PMID: 16675778 PMCID: PMC2662906 DOI: 10.1164/rccm.200509-1459oc] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Nontypeable Haemophilus influenzae (NTHi) commonly infects patients with cystic fibrosis (CF), especially early in childhood. Bacteria biofilms are increasingly recognized as contributing to bacterial persistence and disease pathogenesis in CF. OBJECTIVES This study investigated ability of NTHi to form biofilms and its impact on airway epithelia using in vivo and in vitro analyses. METHODS We evaluated bronchoalveolar lavage fluid from young patients with CF for evidence of NTHi biofilms. To further investigate the pathogenesis of NTHi in respiratory infections, we developed a novel in vitro coculture model of NTHi biofilm formation on polarized human airway epithelial cells grown at the air-liquid interface. MEASUREMENTS AND MAIN RESULTS In bronchoalveolar lavage fluid samples from young, asymptomatic patients with CF, we found morphologic evidence suggestive of NTHi biofilm formation. In addition, 10 clinical NTHi isolates from patients with CF formed biofilms on plastic surfaces. NTHi formed biofilms on the apical surface of cultured airway epithelia. These biofilms exhibited decreased susceptibility to antibiotics and were adherent to epithelial surfaces. Airway epithelial cells remained viable throughout 4 d of coculture, and responded to NTHi with nuclear factor-kappaB signaling, and increased chemokine and cytokine secretion. CONCLUSIONS NTHi formed adherent biofilms on the apical surface airway epithelia with decreased susceptibility to antibiotics, and respiratory cells exhibited inflammatory and host defense responses-evidence of a dynamic host-pathogen interaction. The data presented here have implications both for understanding early CF lung disease pathogenesis and for the treatment of early, asymptomatic colonization of patients with CF with H. influenzae.
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Affiliation(s)
- Timothy D Starner
- The University of Iowa, Department of Pediatrics, 200 Hawkins Drive, Iowa City, IA 52242, USA.
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Severi E, Randle G, Kivlin P, Whitfield K, Young R, Moxon R, Kelly D, Hood D, Thomas GH. Sialic acid transport in Haemophilus influenzae is essential for lipopolysaccharide sialylation and serum resistance and is dependent on a novel tripartite ATP-independent periplasmic transporter. Mol Microbiol 2006; 58:1173-85. [PMID: 16262798 DOI: 10.1111/j.1365-2958.2005.04901.x] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Sialylation of the lipopolysaccharide (LPS) is an important mechanism used by the human pathogen Haemophilus influenzae to evade the innate immune response of the host. We have demonstrated that N-acetylneuraminic acid (Neu5Ac or sialic acid) uptake in H. influenzae is essential for the subsequent modification of the LPS and that this uptake is mediated through a single transport system which is a member of the tripartite ATP-independent periplasmic (TRAP) transporter family. Disruption of either the siaP (HI0146) or siaQM (HI0147) genes, that encode the two subunits of this transporter, results in a complete loss of uptake of [14C]-Neu5Ac. Mutant strains lack sialylated glycoforms in their LPS and are more sensitive to killing by human serum than the parent strain. The SiaP protein has been purified and demonstrated to bind a stoichiometric amount of Neu5Ac by electrospray mass spectrometry. This binding was of high affinity with a Kd of approximately 0.1 microM as determined by protein fluorescence. The inactivation of the SiaPQM TRAP transporter also results in decreased growth of H. influenzae in a chemically defined medium containing Neu5Ac, supporting an additional nutritional role of sialic acid in H. influenzae physiology.
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Sujatha MS, Balaji PV. Fold-recognition and comparative modeling of human alpha2,3-sialyltransferases reveal their sequence and structural similarities to CstII from Campylobacter jejuni. BMC STRUCTURAL BIOLOGY 2006; 6:9. [PMID: 16620397 PMCID: PMC1508147 DOI: 10.1186/1472-6807-6-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2005] [Accepted: 04/19/2006] [Indexed: 11/10/2022]
Abstract
Background The 3-D structure of none of the eukaryotic sialyltransferases (SiaTs) has been determined so far. Sequence alignment algorithms such as BLAST and PSI-BLAST could not detect a homolog of these enzymes from the protein databank. SiaTs, thus, belong to the hard/medium target category in the CASP experiments. The objective of the current work is to model the 3-D structures of human SiaTs which transfer the sialic acid in α2,3-linkage viz., ST3Gal I, II, III, IV, V, and VI, using fold-recognition and comparative modeling methods. The pair-wise sequence similarity among these six enzymes ranges from 41 to 63%. Results Unlike the sequence similarity servers, fold-recognition servers identified CstII, a α2,3/8 dual-activity SiaT from Campylobacter jejuni as the homolog of all the six ST3Gals; the level of sequence similarity between CstII and ST3Gals is only 15–20% and the similarity is restricted to well-characterized motif regions of ST3Gals. Deriving template-target sequence alignments for the entire ST3Gal sequence was not straightforward: the fold-recognition servers could not find a template for the region preceding the L-motif and that between the L- and S-motifs. Multiple structural templates were identified to model these regions and template identification-modeling-evaluation had to be performed iteratively to choose the most appropriate templates. The modeled structures have acceptable stereochemical properties and are also able to provide qualitative rationalizations for some of the site-directed mutagenesis results reported in literature. Apart from the predicted models, an unexpected but valuable finding from this study is the sequential and structural relatedness of family GT42 and family GT29 SiaTs. Conclusion The modeled 3-D structures can be used for docking and other modeling studies and for the rational identification of residues to be mutated to impart desired properties such as altered stability, substrate specificity, etc. Several studies in literature have focused on the development of tools and/or servers for the large-scale/automated modeling of 3-D structures of proteins. In contrast, the present study focuses on modeling the 3-D structure of a specific protein of interest to a biochemist and illustrates the associated difficulties. It is also able to establish a sequence/structure relationship between sialyltransferases of two distinct families.
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Affiliation(s)
- MS Sujatha
- School of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India
| | - Petety V Balaji
- School of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India
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Fox KL, Yildirim HH, Deadman ME, Schweda EKH, Moxon ER, Hood DW. Novel lipopolysaccharide biosynthetic genes containing tetranucleotide repeats in Haemophilus influenzae, identification of a gene for adding O-acetyl groups. Mol Microbiol 2006; 58:207-16. [PMID: 16164559 DOI: 10.1111/j.1365-2958.2005.04814.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Many of the genes for lipopolysaccharide (LPS) biosynthesis in Haemophilus influenzae are phase variable. The mechanism of this variable expression involves slippage of tetranucleotide repeats located within the reading frame of these genes. Based on this, we hypothesized that tetranucleotide repeat sequences might be used to identify as yet unrecognized LPS biosynthetic genes. Synthetic oligonucleotides (20 bases), representing all previously reported LPS-related tetranucleotide repeat sequences in H. influenzae, were used to probe a collection of 25 genetically and epidemiologically diverse strains of non-typeable H. influenzae. A novel gene identified through this strategy was a homologue of oafA, a putative O-antigen LPS acetylase of Salmonella typhimurium, that was present in all 25 non-typeable H. influenzae, 19 of which contained multiple copies of the tetranucleotide 5'-GCAA. Using lacZ fusions, we showed that these tetranucleotide repeats could mediate phase variation of this gene. Structural analysis of LPS showed that a major site of acetylation was the distal heptose (HepIII) of the LPS inner-core. An oafA deletion mutant showed absence of O-acetylation of HepIII. When compared with wild type, oafA mutants displayed increased susceptibility to complement-mediated killing by human serum, evidence that O-acetylation of LPS facilitates resistance to host immune clearance mechanisms. These results provide genetic and structural evidence that H. influenzae oafA is required for phase variable O-acetylation of LPS and functional evidence to support the role of O-acetylation of LPS in pathogenesis.
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Affiliation(s)
- Kate L Fox
- Molecular Infectious Diseases Group, University of Oxford Department of Paediatrics, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford OX3 9DS, UK.
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Allen S, Zaleski A, Johnston JW, Gibson BW, Apicella MA. Novel sialic acid transporter of Haemophilus influenzae. Infect Immun 2005; 73:5291-300. [PMID: 16113244 PMCID: PMC1231074 DOI: 10.1128/iai.73.9.5291-5300.2005] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nontypeable Haemophilus influenzae is an opportunistic pathogen and a common cause of otitis media in children and of chronic bronchitis and pneumonia in patients with chronic obstructive pulmonary disease. The lipooligosaccharides, a major component of the outer membrane of H. influenzae, play an important role in microbial virulence and pathogenicity. N-Acetylneuraminic acid (sialic acid) can be incorporated into the lipooligosaccharides as a terminal nonreducing sugar. Although much of the pathway of sialic acid incorporation into lipooligosaccharides is understood, the transporter responsible for N-acetylneuraminic acid uptake in H. influenzae has yet to be characterized. In this paper we demonstrate that this transporter is a novel sugar transporter of the tripartite ATP-independent periplasmic transporter family. In the absence of this transporter, H. influenzae cannot incorporate sialic acid into its lipooligosaccharides, making the organism unable to survive when exposed to human serum and causing reduced viability in biofilm growth.
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Affiliation(s)
- Simon Allen
- Buck Institute for Age Research, 8001 Redwood Blvd., Novato, California 94945, USA
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Harrison A, Dyer DW, Gillaspy A, Ray WC, Mungur R, Carson MB, Zhong H, Gipson J, Gipson M, Johnson LS, Lewis L, Bakaletz LO, Munson RS. Genomic sequence of an otitis media isolate of nontypeable Haemophilus influenzae: comparative study with H. influenzae serotype d, strain KW20. J Bacteriol 2005; 187:4627-36. [PMID: 15968074 PMCID: PMC1151754 DOI: 10.1128/jb.187.13.4627-4636.2005] [Citation(s) in RCA: 169] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In 1995, the Institute for Genomic Research completed the genome sequence of a rough derivative of Haemophilus influenzae serotype d, strain KW20. Although extremely useful in understanding the basic biology of H. influenzae, these data have not provided significant insight into disease caused by nontypeable H. influenzae, as serotype d strains are not pathogens. In contrast, strains of nontypeable H. influenzae are the primary pathogens of chronic and recurrent otitis media in children. In addition, these organisms have an important role in acute otitis media in children as well as other respiratory diseases. Such strains must therefore contain a gene repertoire that differs from that of strain Rd. Elucidation of the differences between these genomes will thus provide insight into the pathogenic mechanisms of nontypeable H. influenzae. The genome of a representative nontypeable H. influenzae strain, 86-028NP, isolated from a patient with chronic otitis media was therefore sequenced and annotated. Despite large regions of synteny with the strain Rd genome, there are large rearrangements in strain 86-028NP's genome architecture relative to the strain Rd genome. A genomic island similar to an island originally identified in H. influenzae type b is present in the strain 86-028NP genome, while the mu-like phage present in the strain Rd genome is absent from the strain 86-028NP genome. Two hundred eighty open reading frames were identified in the strain 86-028NP genome that were absent from the strain Rd genome. These data provide new insight that complements and extends the ongoing analysis of nontypeable H. influenzae virulence determinants.
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Affiliation(s)
- Alistair Harrison
- Center for Microbial Pathogenesis, Columbus Children's Research Institute, Ohio State University College of Medicine and Public Health, Columbus, Ohio 43205, USA
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