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Cross AR, Roy S, Vivoli Vega M, Rejzek M, Nepogodiev SA, Cliff M, Salmon D, Isupov MN, Field RA, Prior JL, Harmer NJ. Spinning sugars in antigen biosynthesis: characterization of the Coxiella burnetii and Streptomyces griseus TDP-sugar epimerases. J Biol Chem 2022; 298:101903. [PMID: 35398092 PMCID: PMC9095892 DOI: 10.1016/j.jbc.2022.101903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 04/02/2022] [Accepted: 04/04/2022] [Indexed: 11/25/2022] Open
Abstract
The sugars streptose and dihydrohydroxystreptose (DHHS) are unique to the bacteria Streptomyces griseus and Coxiella burnetii, respectively. Streptose forms the central moiety of the antibiotic streptomycin, while DHHS is found in the O-antigen of the zoonotic pathogen C. burnetii. Biosynthesis of these sugars has been proposed to follow a similar path to that of TDP-rhamnose, catalyzed by the enzymes RmlA, RmlB, RmlC, and RmlD, but the exact mechanism is unclear. Streptose and DHHS biosynthesis unusually requires a ring contraction step that could be performed by orthologs of RmlC or RmlD. Genome sequencing of S. griseus and C. burnetii has identified StrM and CBU1838 proteins as RmlC orthologs in these respective species. Here, we demonstrate that both enzymes can perform the RmlC 3'',5'' double epimerization activity necessary to support TDP-rhamnose biosynthesis in vivo. This is consistent with the ring contraction step being performed on a double epimerized substrate. We further demonstrate that proton exchange is faster at the 3''-position than the 5''-position, in contrast to a previously studied ortholog. We additionally solved the crystal structures of CBU1838 and StrM in complex with TDP and show that they form an active site highly similar to those of the previously characterized enzymes RmlC, EvaD, and ChmJ. These results support the hypothesis that streptose and DHHS are biosynthesized using the TDP pathway and that an RmlD paralog most likely performs ring contraction following double epimerization. This work will support the elucidation of the full pathways for biosynthesis of these unique sugars.
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Affiliation(s)
- Alice R Cross
- Living Systems Institute, University of Exeter, Exeter, United Kingdom; Department of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Sumita Roy
- Living Systems Institute, University of Exeter, Exeter, United Kingdom; Department of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Mirella Vivoli Vega
- Living Systems Institute, University of Exeter, Exeter, United Kingdom; Department of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Martin Rejzek
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom
| | - Sergey A Nepogodiev
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom
| | - Matthew Cliff
- Manchester Institute of Biotechnology, University of Manchester, Manchester, United Kingdom
| | - Debbie Salmon
- Department of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Michail N Isupov
- Department of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Robert A Field
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom; Manchester Institute of Biotechnology, University of Manchester, Manchester, United Kingdom
| | - Joann L Prior
- Dstl, Porton Down, Salisbury, Wiltshire, United Kingdom
| | - Nicholas J Harmer
- Living Systems Institute, University of Exeter, Exeter, United Kingdom; Department of Biosciences, University of Exeter, Exeter, United Kingdom.
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Kovacs-Simon A, Metters G, Norville I, Hemsley C, Titball RW. Coxiella burnetii replicates in Galleria mellonella hemocytes and transcriptome mapping reveals in vivo regulated genes. Virulence 2021; 11:1268-1278. [PMID: 32970966 PMCID: PMC7549970 DOI: 10.1080/21505594.2020.1819111] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Larvae of the greater wax moth (Galleria mellonella) are susceptible to infection with C. burnetii, an obligate intracellular bacterial pathogen. We show that bacteria are found in hemocytes after infection, and occupy vacuoles which are morphologically similar to Coxiella-containing vacuoles seen in infected mammalian phagocytes. We characterized the infection by transcriptome profiling of bacteria isolated from the hemocytes of infected larvae and identified 46 highly upregulated genes. The encoded proteins are predicted to be involved in translation, LPS biosynthesis, biotin synthesis, scavenging of reactive oxygen species, and included a T4SS effector and 30 hypothetical proteins. Some of these genes had previously been shown to be upregulated in buffalo green monkey (BGM) cells or in mice, whilst others appear to be regulated in a host-specific manner. Altogether, our results demonstrate the value of the G. mellonella model to study intracellular growth and identify potential virulence factors of C. burnetii.
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Affiliation(s)
- Andrea Kovacs-Simon
- College of Life and Environmental Sciences - Biosciences, University of Exeter , Exeter, UK
| | - Georgie Metters
- College of Life and Environmental Sciences - Biosciences, University of Exeter , Exeter, UK
| | - Isobel Norville
- CBR Division, Defence Science and Technology Laboratory , Porton Down,Salisbury, UK
| | - Claudia Hemsley
- College of Life and Environmental Sciences - Biosciences, University of Exeter , Exeter, UK
| | - Richard W Titball
- College of Life and Environmental Sciences - Biosciences, University of Exeter , Exeter, UK
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Beare PA, Jeffrey BM, Long CM, Martens CM, Heinzen RA. Genetic mechanisms of Coxiella burnetii lipopolysaccharide phase variation. PLoS Pathog 2018; 14:e1006922. [PMID: 29481553 PMCID: PMC5843353 DOI: 10.1371/journal.ppat.1006922] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 03/08/2018] [Accepted: 02/05/2018] [Indexed: 12/30/2022] Open
Abstract
Coxiella burnetii is an intracellular pathogen that causes human Q fever, a disease that normally presents as a severe flu-like illness. Due to high infectivity and disease severity, the pathogen is considered a risk group 3 organism. Full-length lipopolysaccharide (LPS) is required for full virulence and disease by C. burnetii and is the only virulence factor currently defined by infection of an immunocompetent animal. Transition of virulent phase I bacteria with smooth LPS, to avirulent phase II bacteria with rough LPS, occurs during in vitro passage. Semi-rough intermediate forms are also observed. Here, the genetic basis of LPS phase conversion was investigated to obtain a more complete understanding of C. burnetii pathogenesis. Whole genome sequencing of strains producing intermediate and/or phase II LPS identified several common mutations in predicted LPS biosynthesis genes. After passage in broth culture for 30 weeks, phase I strains from different genomic groups exhibited similar phase transition kinetics and elevation of mutations in LPS biosynthesis genes. Targeted mutagenesis and genetic complementation using a new C. burnetii nutritional selection system based on lysine auxotrophy confirmed that six of the mutated genes were necessary for production of phase I LPS. Disruption of two of these genes in a C. burnetii phase I strain resulted in production of phase II LPS, suggesting inhibition of the encoded enzymes could represent a new therapeutic strategy for treatment of Q fever. Additionally, targeted mutagenesis of genes encoding LPS biosynthesis enzymes can now be used to construct new phase II strains from different genomic groups for use in pathogen-host studies at a risk group 2 level.
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Affiliation(s)
- Paul A. Beare
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Brendan M. Jeffrey
- Bioinformatics and Computational Biosciences Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Carrie M. Long
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Craig M. Martens
- Research Technologies Section, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Robert A. Heinzen
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
- * E-mail:
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