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Choi Y, Koh J, Cha SS, Roe JH. Activation of zinc uptake regulator by zinc binding to three regulatory sites. Nucleic Acids Res 2024; 52:4185-4197. [PMID: 38349033 PMCID: PMC11077047 DOI: 10.1093/nar/gkae079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 01/23/2024] [Accepted: 02/05/2024] [Indexed: 05/09/2024] Open
Abstract
Zur is a Fur-family metalloregulator that is widely used to control zinc homeostasis in bacteria. In Streptomyces coelicolor, Zur (ScZur) acts as both a repressor for zinc uptake (znuA) gene and an activator for zinc exporter (zitB) gene. Previous structural studies revealed three zinc ions specifically bound per ScZur monomer; a structural one to allow dimeric architecture and two regulatory ones for DNA-binding activity. In this study, we present evidence that Zur contains a fourth specific zinc-binding site with a key histidine residue (H36), widely conserved among actinobacteria, for regulatory function. Biochemical, genetic, and calorimetric data revealed that H36 is critical for hexameric binding of Zur to the zitB zurbox and further binding to its upstream region required for full activation. A comprehensive thermodynamic model demonstrated that the DNA-binding affinity of Zur to both znuA and zitB zurboxes is remarkably enhanced upon saturation of all three regulatory zinc sites. The model also predicts that the strong coupling between zinc binding and DNA binding equilibria of Zur drives a biphasic activation of the zitB gene in response to a wide concentration change of zinc. Similar mechanisms may be pertinent to other metalloproteins, expanding their response spectrum through binding multiple regulatory metals.
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Affiliation(s)
- Yunchan Choi
- Laboratory of Molecular Microbiology, School of Biological Sciences, College of Natural Science, Seoul National University, Seoul 08826, Republic of Korea
| | - Junseock Koh
- Laboratory of Biophysical Chemistry, School of Biological Sciences, College of Natural Science, Seoul National University, Seoul 08826, Republic of Korea
| | - Sun-Shin Cha
- Protein Research Laboratory, Department of Chemistry and Nanoscience, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Jung-Hye Roe
- Laboratory of Molecular Microbiology, School of Biological Sciences, College of Natural Science, Seoul National University, Seoul 08826, Republic of Korea
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2
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de Crécy-Lagard V, Hutinet G, Cediel-Becerra JDD, Yuan Y, Zallot R, Chevrette MG, Ratnayake RMMN, Jaroch M, Quaiyum S, Bruner S. Biosynthesis and function of 7-deazaguanine derivatives in bacteria and phages. Microbiol Mol Biol Rev 2024; 88:e0019923. [PMID: 38421302 PMCID: PMC10966956 DOI: 10.1128/mmbr.00199-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024] Open
Abstract
SUMMARYDeazaguanine modifications play multifaceted roles in the molecular biology of DNA and tRNA, shaping diverse yet essential biological processes, including the nuanced fine-tuning of translation efficiency and the intricate modulation of codon-anticodon interactions. Beyond their roles in translation, deazaguanine modifications contribute to cellular stress resistance, self-nonself discrimination mechanisms, and host evasion defenses, directly modulating the adaptability of living organisms. Deazaguanine moieties extend beyond nucleic acid modifications, manifesting in the structural diversity of biologically active natural products. Their roles in fundamental cellular processes and their presence in biologically active natural products underscore their versatility and pivotal contributions to the intricate web of molecular interactions within living organisms. Here, we discuss the current understanding of the biosynthesis and multifaceted functions of deazaguanines, shedding light on their diverse and dynamic roles in the molecular landscape of life.
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Affiliation(s)
- Valérie de Crécy-Lagard
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
- University of Florida Genetics Institute, Gainesville, Florida, USA
| | - Geoffrey Hutinet
- Department of Biology, Haverford College, Haverford, Pennsylvania, USA
| | | | - Yifeng Yuan
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Rémi Zallot
- Department of Life Sciences, Manchester Metropolitan University, Manchester, United Kingdom
| | - Marc G. Chevrette
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | | | - Marshall Jaroch
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Samia Quaiyum
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Steven Bruner
- Department of Chemistry, University of Florida, Gainesville, Florida, USA
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3
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Liyayi IK, Forehand AL, Ray JC, Criss AK. Metal piracy by Neisseria gonorrhoeae to overcome human nutritional immunity. PLoS Pathog 2023; 19:e1011091. [PMID: 36730177 PMCID: PMC9894411 DOI: 10.1371/journal.ppat.1011091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Affiliation(s)
- Ian K. Liyayi
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Amy L. Forehand
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Jocelyn C. Ray
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Alison K. Criss
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
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4
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Branch AH, Stoudenmire JL, Seib KL, Cornelissen CN. Acclimation to Nutritional Immunity and Metal Intoxication Requires Zinc, Manganese, and Copper Homeostasis in the Pathogenic Neisseriae. Front Cell Infect Microbiol 2022; 12:909888. [PMID: 35846739 PMCID: PMC9280163 DOI: 10.3389/fcimb.2022.909888] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/18/2022] [Indexed: 12/15/2022] Open
Abstract
Neisseria gonorrhoeae and Neisseria meningitidis are human-specific pathogens in the Neisseriaceae family that can cause devastating diseases. Although both species inhabit mucosal surfaces, they cause dramatically different diseases. Despite this, they have evolved similar mechanisms to survive and thrive in a metal-restricted host. The human host restricts, or overloads, the bacterial metal nutrient supply within host cell niches to limit pathogenesis and disease progression. Thus, the pathogenic Neisseria require appropriate metal homeostasis mechanisms to acclimate to such a hostile and ever-changing host environment. This review discusses the mechanisms by which the host allocates and alters zinc, manganese, and copper levels and the ability of the pathogenic Neisseria to sense and respond to such alterations. This review will also discuss integrated metal homeostasis in N. gonorrhoeae and the significance of investigating metal interplay.
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Affiliation(s)
- Alexis Hope Branch
- Center for Translational Immunology, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, United States
| | - Julie L. Stoudenmire
- Center for Translational Immunology, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, United States
| | - Kate L. Seib
- Institute for Glycomics, Griffith University, Gold Coast, QLD, Australia
| | - Cynthia Nau Cornelissen
- Center for Translational Immunology, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, United States
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5
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Ray JC, Smirnov A, Maurakis SA, Harrison SA, Ke E, Chazin WJ, Cornelissen CN, Criss AK. Adherence Enables Neisseria gonorrhoeae to Overcome Zinc Limitation Imposed by Nutritional Immunity Proteins. Infect Immun 2022; 90:e0000922. [PMID: 35156850 PMCID: PMC8929345 DOI: 10.1128/iai.00009-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 01/07/2022] [Indexed: 11/20/2022] Open
Abstract
Neisseria gonorrhoeae (Gc) must overcome the limitation of metals such as zinc to colonize mucosal surfaces in its obligate human host. While the zinc-binding nutritional immunity proteins calprotectin (S100A8/A9) and psoriasin (S100A7) are abundant in human cervicovaginal lavage fluid, Gc possesses TonB-dependent transporters TdfH and TdfJ that bind and extract zinc from the human version of these proteins, respectively. Here we investigated the contribution of zinc acquisition to Gc infection of epithelial cells of the female genital tract. We found that TdfH and TdfJ were dispensable for survival of strain FA1090 Gc that was associated with Ect1 human immortalized epithelial cells, when zinc was limited by calprotectin and psoriasin. In contrast, suspension-grown bacteria declined in viability under the same conditions. Exposure to murine calprotectin, which Gc cannot use as a zinc source, similarly reduced survival of suspension-grown Gc, but not Ect1-associated Gc. We ruled out epithelial cells as a contributor to the enhanced growth of cell-associated Gc under zinc limitation. Instead, we found that attachment to glass was sufficient to enhance bacterial growth when zinc was sequestered. We compared the transcriptional profiles of WT Gc adherent to glass coverslips or in suspension, when zinc was sequestered with murine calprotectin or provided in excess, from which we identified open reading frames that were increased by zinc sequestration in adherent Gc. One of these, ZnuA, was necessary but not sufficient for survival of Gc under zinc-limiting conditions. These results show that adherence protects Gc from zinc-dependent growth restriction by host nutritional immunity proteins.
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Affiliation(s)
| | - Asya Smirnov
- University of Virginia, Charlottesville, Virginia, USA
| | - Stavros A. Maurakis
- Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia, USA
| | | | - Eugene Ke
- University of Virginia, Charlottesville, Virginia, USA
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6
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The Relationship Between Mucosal Microbiota, Colitis, and Systemic Inflammation in Chronic Granulomatous Disorder. J Clin Immunol 2021; 42:312-324. [PMID: 34731398 DOI: 10.1007/s10875-021-01165-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 10/22/2021] [Indexed: 12/31/2022]
Abstract
PURPOSE Chronic granulomatous disorder (CGD) is a primary immunodeficiency which is frequently complicated by inflammatory colitis and is associated with systemic inflammation. Herein, we aimed to investigate the role of the microbiome in the pathogenesis of colitis and systemic inflammation. METHODS We performed 16S rDNA sequencing on mucosal biopsy samples from each segment of 10 CGD patients' colons and conducted compositional and functional pathway prediction analyses. RESULTS The microbiota in samples from colitis patients demonstrated reduced taxonomic alpha-diversity compared to unaffected patients, even in apparently normal bowel segments. Functional pathway richness was similar between the colitic and non-colitic mucosa, although metabolic pathways involved in butyrate biosynthesis or utilization were enriched in patients with colitis and correlated positively with fecal calprotectin levels. One patient with very severe colitis was dominated by Enterococcus spp., while among other patients Bacteroides spp. abundance correlated with colitis severity measured by fecal calprotectin and an endoscopic severity score. In contrast, Blautia abundance is associated with low severity scores and mucosal health. Several taxa and functional pathways correlated with concentrations of inflammatory cytokines in blood but not with colitis severity. Notably, dividing patients into "high" and "low" systemic inflammation groups demonstrated clearer separation than on the basis of colitis status in beta-diversity analyses. CONCLUSION The microbiome is abnormal in CGD-associated colitis and altered functional characteristics probably contribute to pathogenesis. Furthermore, the relationship between the mucosal microbiome and systemic inflammation, independent of colitis status, implies that the microbiome in CGD can influence the inflammatory phenotype of the condition.
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7
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The zinc transporter ZnuABC is critical for the virulence of Chromobacterium violaceum and contributes to diverse zinc-dependent physiological processes. Infect Immun 2021; 89:e0031121. [PMID: 34370507 DOI: 10.1128/iai.00311-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chromobacterium violaceum is a ubiquitous environmental bacterium that causes sporadic life-threatening infections in humans. How C. violaceum acquires zinc to colonize environmental and host niches is unknown. In this work, we demonstrated that C. violaceum employs the zinc uptake system ZnuABC to overcome zinc limitation in the host, ensuring the zinc supply for several physiological demands. Our data indicated that the C. violaceum ZnuABC transporter is encoded in a zur-CV_RS15045-CV_RS15040-znuCBA operon. This operon was repressed by the zinc uptake regulator Zur and derepressed in the presence of the host protein calprotectin (CP) and the synthetic metal chelator EDTA. A ΔznuCBA mutant strain showed impaired growth under these zinc-chelated conditions. Moreover, the deletion of znuCBA provoked a reduction in violacein production, swimming motility, biofilm formation, and bacterial competition. Remarkably, the ΔznuCBA mutant strain was highly attenuated for virulence in an in vivo mouse infection model and showed a low capacity to colonize the liver, grow in the presence of CP, and resist neutrophil killing. Overall, our findings demonstrate that ZnuABC is essential for C. violaceum virulence, contributing to subvert the zinc-based host nutritional immunity.
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8
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Vibrio cholerae's mysterious Seventh Pandemic island (VSP-II) encodes novel Zur-regulated zinc starvation genes involved in chemotaxis and cell congregation. PLoS Genet 2021; 17:e1009624. [PMID: 34153031 PMCID: PMC8248653 DOI: 10.1371/journal.pgen.1009624] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 07/01/2021] [Accepted: 05/27/2021] [Indexed: 11/19/2022] Open
Abstract
Vibrio cholerae is the causative agent of cholera, a notorious diarrheal disease that is typically transmitted via contaminated drinking water. The current pandemic agent, the El Tor biotype, has undergone several genetic changes that include horizontal acquisition of two genomic islands (VSP-I and VSP-II). VSP presence strongly correlates with pandemicity; however, the contribution of these islands to V. cholerae's life cycle, particularly the 26-kb VSP-II, remains poorly understood. VSP-II-encoded genes are not expressed under standard laboratory conditions, suggesting that their induction requires an unknown signal from the host or environment. One signal that bacteria encounter under both host and environmental conditions is metal limitation. While studying V. cholerae's zinc-starvation response in vitro, we noticed that a mutant constitutively expressing zinc starvation genes (Δzur) congregates at the bottom of a culture tube when grown in a nutrient-poor medium. Using transposon mutagenesis, we found that flagellar motility, chemotaxis, and VSP-II encoded genes were required for congregation. The VSP-II genes encode an AraC-like transcriptional activator (VerA) and a methyl-accepting chemotaxis protein (AerB). Using RNA-seq and lacZ transcriptional reporters, we show that VerA is a novel Zur target and an activator of the nearby AerB chemoreceptor. AerB interfaces with the chemotaxis system to drive oxygen-dependent congregation and energy taxis. Importantly, this work suggests a functional link between VSP-II, zinc-starved environments, and energy taxis, yielding insights into the role of VSP-II in a metal-limited host or aquatic reservoir.
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9
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Kandari D, Joshi H, Bhatnagar R. Zur: Zinc-Sensing Transcriptional Regulator in a Diverse Set of Bacterial Species. Pathogens 2021; 10:344. [PMID: 33804265 PMCID: PMC8000910 DOI: 10.3390/pathogens10030344] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/02/2021] [Accepted: 03/07/2021] [Indexed: 12/18/2022] Open
Abstract
Zinc (Zn) is the quintessential d block metal, needed for survival in all living organisms. While Zn is an essential element, its excess is deleterious, therefore, maintenance of its intracellular concentrations is needed for survival. The living organisms, during the course of evolution, developed proteins that can track the limitation or excess of necessary metal ions, thus providing survival benefits under variable environmental conditions. Zinc uptake regulator (Zur) is a regulatory transcriptional factor of the FUR superfamily of proteins, abundant among the bacterial species and known for its intracellular Zn sensing ability. In this study, we highlight the roles played by Zur in maintaining the Zn levels in various bacterial species as well as the fact that in recent years Zur has emerged not only as a Zn homeostatic regulator but also as a protein involved directly or indirectly in virulence of some pathogens. This functional aspect of Zur could be exploited in the ventures for the identification of newer antimicrobial targets. Despite extensive research on Zur, the insights into its overall regulon and its moonlighting functions in various pathogens yet remain to be explored. Here in this review, we aim to summarise the disparate functional aspects of Zur proteins present in various bacterial species.
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Affiliation(s)
- Divya Kandari
- Molecular Biology and Genetic Engineering Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India; (D.K.); (H.J.)
| | - Hemant Joshi
- Molecular Biology and Genetic Engineering Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India; (D.K.); (H.J.)
| | - Rakesh Bhatnagar
- Molecular Biology and Genetic Engineering Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India; (D.K.); (H.J.)
- Banaras Hindu University, Banaras 221005, India
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10
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Sevilla E, Bes MT, Peleato ML, Fillat MF. Fur-like proteins: Beyond the ferric uptake regulator (Fur) paralog. Arch Biochem Biophys 2021; 701:108770. [PMID: 33524404 DOI: 10.1016/j.abb.2021.108770] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 01/12/2021] [Accepted: 01/17/2021] [Indexed: 10/22/2022]
Abstract
Proteins belonging to the FUR (ferric uptake regulator) family are the cornerstone of metalloregulation in most prokaryotes. Although numerous reviews have been devoted to these proteins, these reports are mainly focused on the Fur paralog that gives name to the family. In the last years, the increasing knowledge on the other, less ubiquitous members of this family has evidenced their importance in bacterial metabolism. As the Fur paralog, the major regulator of iron homeostasis, Zur, Irr, BosR and PerR are tightly related to stress defenses and host-pathogen interaction being in many cases essential for virulence. Furthermore, the Nur and Mur paralogs largely contribute to control nickel and manganese homeostasis, which are cofactors of pivotal proteins for host colonization and bacterial redox homeostasis. The present review highlights the main features of FUR proteins that differ to the canonical Fur paralog either in the coregulatory metal, such as Zur, Nur and Mur, or in the action mechanism to control target genes, such as PerR, Irr and BosR.
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Affiliation(s)
- Emma Sevilla
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain
| | - M Teresa Bes
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain
| | - M Luisa Peleato
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain
| | - María F Fillat
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain.
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11
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Maurakis S, Cornelissen CN. Metal-Limited Growth of Neisseria gonorrhoeae for Characterization of Metal-Responsive Genes and Metal Acquisition from Host Ligands. J Vis Exp 2020. [PMID: 32202529 DOI: 10.3791/60903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Trace metals such as iron and zinc are vital nutrients known to play key roles in prokaryotic processes including gene regulation, catalysis, and protein structure. Metal sequestration by hosts often leads to metal limitation for the bacterium. This limitation induces bacterial gene expression whose protein products allow bacteria to overcome their metal-limited environment. Characterization of such genes is challenging. Bacteria must be grown in meticulously prepared media that allows sufficient access to nutritional metals to permit bacterial growth while maintaining a metal profile conducive to achieving expression of the aforementioned genes. As such, a delicate balance must be established for the concentrations of these metals. Growing a nutritionally fastidious organism such as Neisseria gonorrhoeae, which has evolved to survive only in the human host, adds an additional level of complexity. Here, we describe the preparation of a defined metal-limited medium sufficient to allow gonococcal growth and the desired gene expression. This method allows the investigator to chelate iron and zinc from undesired sources while supplementing the media with defined sources of iron or zinc, whose preparation is also described. Finally, we outline three experiments that utilize this media to help characterize the protein products of metal-regulated gonococcal genes.
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12
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Abstract
The rhizobium-legume symbiosis contributes around 65% of biological nitrogen fixation in agriculture systems and is critical for sustainable agriculture by reducing the amount of chemical nitrogen fertilizer being used. Rhizobial inocula have been commercialized for more than 100 years, but the efficiency of inoculation can vary among legume cultivars, field sites, and years. These long-lasting challenging problems impede the establishment of a sustainable agriculture, particularly in developing countries. Here, we report that rhizobial zinc starvation machinery containing a conserved high-affinity zinc transporter and accessory components makes cumulative contributions to modulating rhizobial symbiotic compatibility. This work highlights a critical role of largely unexplored nutritional immunity in the rhizobium-legume symbiosis, which makes zinc starvation machinery an attractive target for improving rhizobial symbiotic compatibility. Pathogenic bacteria need high-affinity zinc uptake systems to counteract the nutritional immunity exerted by infected hosts. However, our understanding of zinc homeostasis in mutualistic systems such as the rhizobium-legume symbiosis is limited. Here, we show that the conserved high-affinity zinc transporter ZnuABC and accessory transporter proteins (Zip1, Zip2, and c06450) made cumulative contributions to nodulation of the broad-host-range strain Sinorhizobium fredii CCBAU45436. Zur acted as a zinc-dependent repressor for the znuC-znuB-zur operon, znuA, and c06450 by binding to the associated Zur box, but did not regulate zip1 and zip2. ZnuABC was the major zinc transporter. Combined mutants lacking znuA and one of the three accessory genes had more severe defects in nodulation and growth under zinc starvation conditions than the znuA mutant, though rhizoplane colonization by these mutants was not impaired. In contrast to the elite strain CCBAU45436, more drastic symbiotic defects were observed for the znuA mutants of other Sinorhizobium strains, which lack at least one of the three accessory genes in their genomes and are characterized by their limited host range and geographical distribution. The znu-derived mutants showed a higher expression level of nod genes involved in Nod factor biosynthesis and a reduced expression of genes encoding a type three secretion system and its effector NopP, which can interfere with the host immune system. Application of exogenous zinc restored the nodulation ability of these znu-derived mutants. Therefore, the conserved ZnuABC and accessory components in the zinc starvation machinery play an important role in modulating symbiotic compatibility.
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13
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Mobarak Qamsari M, Rasooli I, Darvish Alipour Astaneh S. Identification and immunogenic properties of recombinant ZnuD protein loops of Acinetobacter baumannii. INFORMATICS IN MEDICINE UNLOCKED 2020. [DOI: 10.1016/j.imu.2020.100342] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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14
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Lonergan ZR, Skaar EP. Nutrient Zinc at the Host-Pathogen Interface. Trends Biochem Sci 2019; 44:1041-1056. [PMID: 31326221 PMCID: PMC6864270 DOI: 10.1016/j.tibs.2019.06.010] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/13/2019] [Accepted: 06/25/2019] [Indexed: 12/12/2022]
Abstract
Zinc is an essential cofactor required for life and, as such, mechanisms exist for its homeostatic maintenance in biological systems. Despite the evolutionary distance between vertebrates and microbial life, there are parallel mechanisms to balance the essentiality of zinc with its inherent toxicity. Vertebrates regulate zinc homeostasis through a complex network of metal transporters and buffering systems that respond to changes in nutritional zinc availability or inflammation. Fine-tuning of this network becomes crucial during infections, where host nutritional immunity attempts to limit zinc availability to pathogens. However, accumulating evidence demonstrates that pathogens have evolved mechanisms to subvert host-mediated zinc withholding, and these metal homeostasis systems are important for survival within the host. We discuss here the mechanisms of vertebrate and bacterial zinc homeostasis and mobilization, as well as recent developments in our understanding of microbial zinc acquisition.
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Affiliation(s)
- Zachery R Lonergan
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA; Microbe-Host Interactions Training Program, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA.
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15
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Seib KL, Haag AF, Oriente F, Fantappiè L, Borghi S, Semchenko EA, Schulz BL, Ferlicca F, Taddei AR, Giuliani MM, Pizza M, Delany I. The meningococcal vaccine antigen GNA2091 is an analogue of YraP and plays key roles in outer membrane stability and virulence. FASEB J 2019; 33:12324-12335. [DOI: 10.1096/fj.201900669r] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Kate L. Seib
- Institute for GlycomicsGriffith UniversityGold CoastQueenslandAustralia
| | | | | | | | | | | | - Benjamin L. Schulz
- School of Chemistry and Molecular BiosciencesThe University of QueenslandBrisbaneQueenslandAustralia
| | | | - Anna Rita Taddei
- Interdepartmental Centre of Electron Microscopy (CIME)Tuscia UniversityTusciaItaly
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16
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Maurakis S, Keller K, Maxwell CN, Pereira K, Chazin WJ, Criss AK, Cornelissen CN. The novel interaction between Neisseria gonorrhoeae TdfJ and human S100A7 allows gonococci to subvert host zinc restriction. PLoS Pathog 2019; 15:e1007937. [PMID: 31369630 PMCID: PMC6692053 DOI: 10.1371/journal.ppat.1007937] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 08/13/2019] [Accepted: 06/21/2019] [Indexed: 01/12/2023] Open
Abstract
Neisseria gonorrhoeae causes the sexually-transmitted infection gonorrhea, a global disease that is difficult to treat and for which there is no vaccine. This pathogen employs an arsenal of conserved outer membrane proteins called TonB-dependent transporters (TdTs) that allow the gonococcus to overcome nutritional immunity, the host strategy of sequestering essential nutrients away from invading bacteria to handicap infectious ability. N. gonorrhoeae produces eight known TdTs, of which four are utilized for acquisition of iron or iron chelates from host-derived proteins or xenosiderophores produced by other bacteria. Of the remaining TdTs, two of them, TdfH and TdfJ, facilitate zinc uptake. TdfH was recently shown to bind Calprotectin, a member of the S100 protein family, and subsequently extract its zinc, which is then internalized by N. gonorrhoeae. Like Calprotectin, other S100s are also capable of binding transition metals such as zinc and copper, and thus have demonstrated growth suppression of numerous other pathogens via metal sequestration. Considering the functional and structural similarities of the TdTs and of the S100s, as well as the upregulation in response to Zn limitation shown by TdfH and TdfJ, we sought to evaluate whether other S100s have the ability to support gonococcal growth by means of zinc acquisition and to frame this growth in the context of the TdTs. We found that both S100A7 and S10012 are utilized by N. gonorrhoeae as a zinc source in a mechanism that depends on the zinc transport system ZnuABC. Moreover, TdfJ binds directly to S100A7, from which it internalizes zinc. This interaction is restricted to the human version of S100A7, and zinc presence in S100A7 is required to fully support gonococcal growth. These studies highlight how gonococci co-opt human nutritional immunity, by presenting a novel interaction between TdfJ and human S100A7 for overcoming host zinc restriction. Neisseria gonorrhoeae causes the common sexually-transmitted infection gonorrhea. This bacteria’s ability to rapidly acquire antibiotic resistance factors, coupled with the lack of any effective vaccine to prevent infection, has resulted in a disease that poses a global threat and may become untreatable. A group of gonococcal outer membrane proteins called TonB-dependent transporters (TdTs) have been implicated as promising vaccine targets, as they are well-conserved and expressed across gonococcal isolates and play a vital role in allowing the pathogen to acquire essential nutrients during infection of the human host. Here, we describe the conservation and regulation of TdfJ, a gonococcal TdT whose homologues are ubiquitous in the genus Neisseria. We show that TdfJ binds directly to S100A7, a host protein that normally sequesters zinc away from invading pathogens. This novel interaction enables N. gonorrhoeae to strip S100A7 of chelated zinc for its own use. Furthermore, we show that another zinc-binding human protein, S100A12, is also utilized by N. gonorrhoeae as a zinc source by an as-yet-unidentified mechanism. This study provides insight into the functional role of the TdTs during infection and highlights these proteins as promising targets for both vaccine and antimicrobial therapy development.
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Affiliation(s)
- Stavros Maurakis
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, VA, United States of America
| | - Kayla Keller
- Biomedical Sciences Doctoral Portal, Virginia Commonwealth University School of Medicine, Richmond, VA, United States of America
| | - C. Noel Maxwell
- Departments of Biochemistry and Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Kevin Pereira
- Departments of Biochemistry and Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Walter J. Chazin
- Departments of Biochemistry and Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Alison K. Criss
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, United States of America
| | - Cynthia Nau Cornelissen
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, VA, United States of America
- Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, United States of America
- * E-mail:
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17
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Abstract
Bacteria encode a variety of adaptations that enable them to survive during zinc starvation, a condition which is encountered both in natural environments and inside the human host. In Vibrio cholerae, the causative agent of the diarrheal disease cholera, we have identified a novel member of this zinc starvation response, a cell wall hydrolase that retains function and is conditionally essential for cell growth in low-zinc environments. Other Gram-negative bacteria contain homologs that appear to be under similar regulatory control. These findings are significant because they represent, to our knowledge, the first evidence that zinc homeostasis influences cell wall turnover. Anti-infective therapies commonly target the bacterial cell wall; therefore, an improved understanding of how the cell wall adapts to host-induced zinc starvation could lead to new antibiotic development. Such therapeutic interventions are required to combat the rising threat of drug-resistant infections. The cell wall is a strong, yet flexible, meshwork of peptidoglycan (PG) that gives a bacterium structural integrity. To accommodate a growing cell, the wall is remodeled by both PG synthesis and degradation. Vibrio cholerae encodes a group of three nearly identical zinc-dependent endopeptidases (EPs) that are predicted to hydrolyze PG to facilitate cell growth. Two of these (ShyA and ShyC) are conditionally essential housekeeping EPs, while the third (ShyB) is not expressed under standard laboratory conditions. To investigate the role of ShyB, we conducted a transposon screen to identify mutations that activate shyB transcription. We found that shyB is induced as part of the Zur-mediated zinc starvation response, a mode of regulation not previously reported for cell wall lytic enzymes. In vivo, ShyB alone was sufficient to sustain cell growth in low-zinc environments. In vitro, ShyB retained its d,d-endopeptidase activity against purified sacculi in the presence of the metal chelator EDTA at concentrations that inhibit ShyA and ShyC. This insensitivity to metal chelation is likely what enables ShyB to substitute for other EPs during zinc starvation. Our survey of transcriptomic data from diverse bacteria identified other candidate Zur-regulated EPs, suggesting that this adaptation to zinc starvation is employed by other Gram-negative bacteria.
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18
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Kandari D, Gopalani M, Gupta M, Joshi H, Bhatnagar S, Bhatnagar R. Identification, Functional Characterization, and Regulon Prediction of the Zinc Uptake Regulator ( zur) of Bacillus anthracis - An Insight Into the Zinc Homeostasis of the Pathogen. Front Microbiol 2019; 9:3314. [PMID: 30687290 PMCID: PMC6336718 DOI: 10.3389/fmicb.2018.03314] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 12/19/2018] [Indexed: 11/29/2022] Open
Abstract
Zinc has an abounding occurrence in the prokaryotes and plays paramount roles including catalytic, structural, and regulatory. Zinc uptake regulator (Zur), a Fur family transcriptional regulator, is connoted in maintaining zinc homeostasis in the pathogenic bacteria by binding to zinc and regulating the genes involved in zinc uptake and mobilization. Zinc homeostasis has been marginally scrutinized in Bacillus anthracis, the top-rated bio-terror agent, with no decipherment of the role of Zur. Of the three Fur family regulators in B. anthracis, BAS4181 is annotated as a zinc-specific transcriptional regulator. This annotation was further substantiated by our stringent computational and experimental analyses. The residues critical for zinc and DNA binding were delineated by homology modeling and sequence/structure analysis. ba zur existed as a part of a three-gene operon. Purified BaZur prodigiously existed in the dimeric form, indicated by size exclusion chromatography and blue native-polyacrylamide gel electrophoresis (PAGE). Computational and manual strategies were employed to decipher the putative regulon of ba zur, comprising of 11 genes, controlled by six promoters, each harboring at least one Zur box. The DNA binding capability of the purified BaZur to the upstream regions of the ba zur operon, yciC, rpmG, znuA, and genes encoding a GTPase cobalamine synthesis protein and a permease was ascertained by electrophoretic mobility shift assays. The regulon genes, implicated in zinc uptake and mobilization, were mostly negatively regulated by BaZur. The ba zur expression was downregulated upon exposure of cells to an excess of zinc. Conversely, it exhibited a marked upregulation under N, N, N', N'-Tetrakis (2-pyridylmethyl) ethylenediamine (TPEN) mediated zinc-depleted environment, adding credence to its negative autoregulation. Moreover, an increase in the transcript levels of the regulon genes znuA, rpmG, and yciC upon exposure of cells to TPEN connoted their role in combating hypo-zincemic conditions by bringing about zinc uptake and mobilization. Thus, this study functionally characterizes Zur of B. anthracis and elucidates its role in maintaining zinc homeostasis.
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Affiliation(s)
- Divya Kandari
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Monisha Gopalani
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Manish Gupta
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Hemant Joshi
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Sonika Bhatnagar
- Computational and Structural Biology Laboratory, Division of Biotechnology, Netaji Subhas Institute of Technology, University of Delhi, New Delhi, India
| | - Rakesh Bhatnagar
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
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19
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Bacterial zinc uptake regulator proteins and their regulons. Biochem Soc Trans 2018; 46:983-1001. [PMID: 30065104 PMCID: PMC6103462 DOI: 10.1042/bst20170228] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 06/25/2018] [Accepted: 06/26/2018] [Indexed: 01/10/2023]
Abstract
All organisms must regulate the cellular uptake, efflux, and intracellular trafficking of essential elements, including d-block metal ions. In bacteria, such regulation is achieved by the action of metal-responsive transcriptional regulators. Among several families of zinc-responsive transcription factors, the ‘zinc uptake regulator’ Zur is the most widespread. Zur normally represses transcription in its zinc-bound form, in which DNA-binding affinity is enhanced allosterically. Experimental and bioinformatic searches for Zur-regulated genes have revealed that in many cases, Zur proteins govern zinc homeostasis in a much more profound way than merely through the expression of uptake systems. Zur regulons also comprise biosynthetic clusters for metallophore synthesis, ribosomal proteins, enzymes, and virulence factors. In recognition of the importance of zinc homeostasis at the host–pathogen interface, studying Zur regulons of pathogenic bacteria is a particularly active current research area.
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20
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Cornelissen CN. Subversion of nutritional immunity by the pathogenic Neisseriae. Pathog Dis 2018; 76:4553517. [PMID: 29045638 PMCID: PMC6251569 DOI: 10.1093/femspd/ftx112] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 10/12/2017] [Indexed: 12/21/2022] Open
Abstract
The pathogenic Neisseria species, including Neisseria meningitidis and Neisseria gonorrhoeae, are obligate human pathogens that cause significant morbidity and mortality. The success of these pathogens, with regard to causing disease in humans, is inextricably linked to their ability to acquire necessary nutrients in the hostile environment of the host. Humans deploy a significant arsenal of weaponry to defend against bacterial pathogens, not least of which are the metal-sequestering proteins that entrap and withhold transition metals, including iron, zinc and manganese, from invaders. This review will discuss the general strategies that bacteria employ to overcome these metal-sequestering attempts by the host, and then will focus on the relatively uncommon 'metal piracy' approaches utilized by the pathogenic Neisseria for this purpose. Because acquiring metals from the environment is critical to microbial survival, interfering with this process could impede growth and therefore disease initiation or progression. This review will also discuss how interfering with metal uptake by the pathogenic Neisseriae could be deployed in the development of novel or improved preventative or therapeutic measures against these important pathogens.
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Affiliation(s)
- Cynthia Nau Cornelissen
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Box 980678, Richmond, VA 23298-0678, USA
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21
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Zinc Acquisition Mechanisms Differ between Environmental and Virulent Francisella Species. J Bacteriol 2018; 200:JB.00587-17. [PMID: 29109188 PMCID: PMC5786701 DOI: 10.1128/jb.00587-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 10/27/2017] [Indexed: 12/29/2022] Open
Abstract
Zinc is an essential nutrient for bacterial growth. Because host cells can restrict pathogen access to zinc as an antimicrobial defense mechanism, intracellular pathogens such as Francisella must sense their environment and acquire zinc in response. In many bacteria, the conserved transcription factor Zur is a key regulator of zinc acquisition. To identify mechanisms of zinc uptake in Francisella novicida U112, transcriptome sequencing of wild-type and putative zur mutant bacteria was performed. Only three genes were confirmed as directly regulated by Zur and zinc limitation by quantitative reverse transcription-PCR. One of these genes, FTN_0879, is predicted to encode a protein with similarity to the zupT family of zinc transporters, which are not typically regulated by Zur. While a putative znuACB operon encoding a high-affinity zinc transporter was identified in U112, expression of this operon was not controlled by Zur or zinc concentration. Disruption of zupT but not znuA in U112 impaired growth under zinc limitation, suggesting that ZupT is the primary mechanism of zinc acquisition under these conditions. In the virulent Francisella tularensis subsp. tularensis Schu S4 strain, zupT is a pseudogene, and attempts to delete znuA were unsuccessful, suggesting that it is essential in this strain. A reverse TetR repression system was used to knock down the expression of znuA in Schu S4, revealing that znuA is required for growth under zinc limitation and contributes to intracellular growth within macrophages. Overall, this work identifies genes necessary for adaptation to zinc limitation and highlights nutritional differences between environmental and virulent Francisella strains. IMPORTANCEFrancisella tularensis is a tier 1 select agent with a high potential for lethality and no approved vaccine. A better understanding of Francisella virulence factors is required for the development of therapeutics. While acquisition of zinc has been shown to be required for the virulence of numerous intracellular pathogens, zinc uptake has not been characterized in Francisella. This work characterizes the Zur regulon in F. novicida and identifies two transporters that contribute to bacterial growth under zinc limitation. In addition, these data identify differences in mechanisms of zinc uptake and tolerance to zinc limitation between F. tularensis and F. novicida, highlighting the role of znuA in the growth of Schu S4 under zinc limitation.
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22
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Lhospice S, Gomez NO, Ouerdane L, Brutesco C, Ghssein G, Hajjar C, Liratni A, Wang S, Richaud P, Bleves S, Ball G, Borezée-Durant E, Lobinski R, Pignol D, Arnoux P, Voulhoux R. Pseudomonas aeruginosa zinc uptake in chelating environment is primarily mediated by the metallophore pseudopaline. Sci Rep 2017; 7:17132. [PMID: 29214991 PMCID: PMC5719457 DOI: 10.1038/s41598-017-16765-9] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 11/16/2017] [Indexed: 11/09/2022] Open
Abstract
Metal uptake is vital for all living organisms. In metal scarce conditions a common bacterial strategy consists in the biosynthesis of metallophores, their export in the extracellular medium and the recovery of a metal-metallophore complex through dedicated membrane transporters. Staphylopine is a recently described metallophore distantly related to plant nicotianamine that contributes to the broad-spectrum metal uptake capabilities of Staphylococcus aureus. Here we characterize a four-gene operon (PA4837-PA4834) in Pseudomonas aeruginosa involved in the biosynthesis and trafficking of a staphylopine-like metallophore named pseudopaline. Pseudopaline differs from staphylopine with regard to the stereochemistry of its histidine moiety associated with an alpha ketoglutarate moiety instead of pyruvate. In vivo, the pseudopaline operon is regulated by zinc through the Zur repressor. The pseudopaline system is involved in nickel uptake in poor media, and, most importantly, in zinc uptake in metal scarce conditions mimicking a chelating environment, thus reconciling the regulation of the cnt operon by zinc with its function as the main zinc importer under these metal scarce conditions.
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Affiliation(s)
- Sébastien Lhospice
- CNRS et Aix-Marseille Université, Laboratoire d'Ingénierie des Systèmes Macromoléculaires (UMR7255), Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Nicolas Oswaldo Gomez
- CNRS et Aix-Marseille Université, Laboratoire d'Ingénierie des Systèmes Macromoléculaires (UMR7255), Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Laurent Ouerdane
- Université de Pau et des Pays de l'Adour/CNRS, Laboratoire de Chimie Analytique Bio-inorganique et Environnement, IPREM-UMR5254, Hélioparc, 2, Avenue Angot, 64053, Pau, France
| | - Catherine Brutesco
- CEA, CNRS and Aix-Marseille Université, Institut de Biosciences et Biotechnologies d'Aix-Marseille, UMR 7265 LBC, CEA Cadarache, Saint-Paul-lez-Durance, F-13108, France
| | - Ghassan Ghssein
- CEA, CNRS and Aix-Marseille Université, Institut de Biosciences et Biotechnologies d'Aix-Marseille, UMR 7265 LBC, CEA Cadarache, Saint-Paul-lez-Durance, F-13108, France
| | - Christine Hajjar
- CEA, CNRS and Aix-Marseille Université, Institut de Biosciences et Biotechnologies d'Aix-Marseille, UMR 7265 LBC, CEA Cadarache, Saint-Paul-lez-Durance, F-13108, France
| | - Ahmed Liratni
- CNRS et Aix-Marseille Université, Laboratoire d'Ingénierie des Systèmes Macromoléculaires (UMR7255), Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Shuanglong Wang
- Université de Pau et des Pays de l'Adour/CNRS, Laboratoire de Chimie Analytique Bio-inorganique et Environnement, IPREM-UMR5254, Hélioparc, 2, Avenue Angot, 64053, Pau, France
| | - Pierre Richaud
- CEA, CNRS and Aix-Marseille Université, Institut de Biosciences et Biotechnologies d'Aix-Marseille, UMR 7265 LB3M, CEA Cadarache, Saint-Paul-lez Durance, F-13108, France
| | - Sophie Bleves
- CNRS et Aix-Marseille Université, Laboratoire d'Ingénierie des Systèmes Macromoléculaires (UMR7255), Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Geneviève Ball
- CNRS et Aix-Marseille Université, Laboratoire d'Ingénierie des Systèmes Macromoléculaires (UMR7255), Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Elise Borezée-Durant
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Ryszard Lobinski
- Université de Pau et des Pays de l'Adour/CNRS, Laboratoire de Chimie Analytique Bio-inorganique et Environnement, IPREM-UMR5254, Hélioparc, 2, Avenue Angot, 64053, Pau, France
| | - David Pignol
- CEA, CNRS and Aix-Marseille Université, Institut de Biosciences et Biotechnologies d'Aix-Marseille, UMR 7265 LBC, CEA Cadarache, Saint-Paul-lez-Durance, F-13108, France
| | - Pascal Arnoux
- CEA, CNRS and Aix-Marseille Université, Institut de Biosciences et Biotechnologies d'Aix-Marseille, UMR 7265 LBC, CEA Cadarache, Saint-Paul-lez-Durance, F-13108, France.
| | - Romé Voulhoux
- CNRS et Aix-Marseille Université, Laboratoire d'Ingénierie des Systèmes Macromoléculaires (UMR7255), Institut de Microbiologie de la Méditerranée, Marseille, France.
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23
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The Components of the Unique Zur Regulon of Cupriavidus metallidurans Mediate Cytoplasmic Zinc Handling. J Bacteriol 2017; 199:JB.00372-17. [PMID: 28808127 DOI: 10.1128/jb.00372-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 08/03/2017] [Indexed: 12/13/2022] Open
Abstract
Zinc is an essential trace element, yet it is toxic at high concentrations. In the betaproteobacterium Cupriavidus metallidurans, the highly efficient removal of surplus zinc from the periplasm is responsible for the outstanding metal resistance of the organism. Rather than having a typical Zur-dependent, high-affinity ATP-binding cassette transporter of the ABC protein superfamily for zinc uptake at low concentrations, C. metallidurans has the secondary zinc importer ZupT of the zinc-regulated transporter, iron-regulated transporter (ZRT/IRT)-like protein (ZIP) family. It is important to understand, therefore, how this zinc-resistant bacterium copes with exposure to low zinc concentrations. Members of the Zur regulon in C. metallidurans were identified by comparing the transcriptomes of a Δzur mutant and its parent strain. The consensus sequence of the Zur-binding box was derived for the zupTp promoter-regulatory region by use of a truncation assay. The motif was used to predict possible Zur boxes upstream of Zur regulon members. The binding of Zur to these boxes was confirmed. Two Zur boxes upstream of the cobW 1 gene, encoding a putative zinc chaperone, proved to be required for complete repression of cobW 1 and its downstream genes in cells cultivated in mineral salts medium. A Zur box upstream of each of zur-cobW 2, cobW 3, and zupT permitted both low expression levels of these genes and their upregulation under conditions of zinc starvation. This demonstrates a compartmentalization of zinc homeostasis in C. metallidurans, where the periplasm is responsible for the removal of surplus zinc, cytoplasmic components are responsible for the management of zinc as an essential cofactor, and the two compartments are connected by ZupT.IMPORTANCE Elucidating zinc homeostasis is necessary for understanding both host-pathogen interactions and the performance of free-living bacteria in their natural environments. Escherichia coli acquires zinc under conditions of low zinc concentrations via the Zur-controlled ZnuABC importer of the ABC superfamily, and this was also the paradigm for other bacteria. In contrast, the heavy-metal-resistant bacterium C. metallidurans achieves high tolerance to zinc through sophisticated zinc handling and efflux systems operating on periplasmic zinc ions, so that removal of surplus zinc is a periplasmic feature in this bacterium. It is shown here that this process is augmented by the management of zinc by cytoplasmic zinc chaperones, whose synthesis is controlled by the Zur regulator. This demonstrates a new mechanism, involving compartmentalization, for organizing zinc homeostasis.
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24
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Huis In 't Veld RAG, Kramer G, van der Ende A, Speijer D, Pannekoek Y. The Hfq regulon of Neisseria meningitidis. FEBS Open Bio 2017; 7:777-788. [PMID: 28593133 PMCID: PMC5458458 DOI: 10.1002/2211-5463.12218] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Revised: 02/07/2017] [Accepted: 03/09/2017] [Indexed: 01/09/2023] Open
Abstract
The conserved RNA‐binding protein, Hfq, has multiple regulatory roles within the prokaryotic cell, including promoting stable duplex formation between small RNAs and mRNAs, and thus hfq deletion mutants have pleiotropic phenotypes. Previous proteome and transcriptome studies of Neisseria meningitidis have generated limited insight into differential gene expression due to Hfq loss. In this study, reversed‐phase liquid chromatography combined with data‐independent alternate scanning mass spectrometry (LC‐MSE) was utilized for rapid high‐resolution quantitative proteomic analysis to further elucidate the differentially expressed proteome of a meningococcal hfq deletion mutant. Whole‐cell lysates of N. meningitidis serogroup B H44/76 wild‐type (wt) and H44/76Δhfq (Δhfq) grown in liquid growth medium were subjected to tryptic digestion. The resulting peptide mixtures were separated by liquid chromatography (LC) prior to analysis by mass spectrometry (MSE). Differential expression was analyzed by Student's t‐test with control for false discovery rate (FDR). Reliable quantitation of relative expression comparing wt and Δhfq was achieved with 506 proteins (20%). Upon FDR control at q ≤ 0.05, 48 up‐ and 59 downregulated proteins were identified. From these, 81 were identified as novel Hfq‐regulated candidates, while 15 proteins were previously found by SDS/PAGE/MS and 24 with microarray analyses. Thus, using LC‐MSE we have expanded the repertoire of Hfq‐regulated proteins. In conjunction with previous studies, a comprehensive network of Hfq‐regulated proteins was constructed and differentially expressed proteins were found to be involved in a large variety of cellular processes. The results and comparisons with other gram‐negative model systems, suggest still unidentified sRNA analogs in N. meningitidis.
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Affiliation(s)
- Robert A G Huis In 't Veld
- Department of Medical Microbiology Center of Infection and Immunity Amsterdam (CINIMA) Academic Medical Center Amsterdam The Netherlands
| | - Gertjan Kramer
- Clinical Proteomics Facility Department of Medical Biochemistry Academic Medical Center Amsterdam The Netherlands.,Present address: Genome Biology Unit EMBL Heidelberg Heidelberg Germany
| | - Arie van der Ende
- Department of Medical Microbiology Center of Infection and Immunity Amsterdam (CINIMA) Academic Medical Center Amsterdam The Netherlands.,Reference Laboratory for Bacterial Meningitis Department of Medical Microbiology Academic Medical Center Amsterdam The Netherlands
| | - Dave Speijer
- Clinical Proteomics Facility Department of Medical Biochemistry Academic Medical Center Amsterdam The Netherlands
| | - Yvonne Pannekoek
- Department of Medical Microbiology Center of Infection and Immunity Amsterdam (CINIMA) Academic Medical Center Amsterdam The Netherlands
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25
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Choi SH, Lee KL, Shin JH, Cho YB, Cha SS, Roe JH. Zinc-dependent regulation of zinc import and export genes by Zur. Nat Commun 2017; 8:15812. [PMID: 28598435 PMCID: PMC5472717 DOI: 10.1038/ncomms15812] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 05/04/2017] [Indexed: 12/21/2022] Open
Abstract
In most bacteria, zinc depletion is sensed by Zur, whereas the surplus is sensed by different regulators to achieve zinc homeostasis. Here we present evidence that zinc-bound Zur not only represses genes for zinc acquisition but also induces the zitB gene encoding a zinc exporter in Streptomyces coelicolor, a model actinobacteria. Zinc-dependent gene regulation by Zur occurs in two phases. At sub-femtomolar zinc concentrations (phase I), dimeric Zur binds to the Zur-box motif immediately upstream of the zitB promoter, resulting in low zitB expression. At the same time, Zur represses genes for zinc uptake. At micromolar zinc concentrations (phase II), oligomeric Zur binding with footprint expansion upward from the Zur box results in high zitB induction. Our findings reveal a mode of zinc-dependent gene activation that uses a single metalloregulator to control genes for both uptake and export over a wide range of zinc concentrations. Zinc homeostasis in most bacteria is achieved by a set of regulators, each responding to a certain level of intracellular zinc. Here the authors show that, in Streptomyces coelicolor, the Zur regulator modulates the expression of genes for zinc import and export over a large range of zinc concentrations.
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Affiliation(s)
- Seung-Hwan Choi
- Laboratory of Molecular Microbiology, School of Biological Sciences, and Institute of Microbiology, Seoul National University, Seoul 151-742, Korea
| | - Kang-Lok Lee
- Laboratory of Molecular Microbiology, School of Biological Sciences, and Institute of Microbiology, Seoul National University, Seoul 151-742, Korea
| | - Jung-Ho Shin
- Laboratory of Molecular Microbiology, School of Biological Sciences, and Institute of Microbiology, Seoul National University, Seoul 151-742, Korea
| | - Yoo-Bok Cho
- Laboratory of Molecular Microbiology, School of Biological Sciences, and Institute of Microbiology, Seoul National University, Seoul 151-742, Korea
| | - Sun-Shin Cha
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Jung-Hye Roe
- Laboratory of Molecular Microbiology, School of Biological Sciences, and Institute of Microbiology, Seoul National University, Seoul 151-742, Korea
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26
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Neupane DP, Jacquez B, Sundararajan A, Ramaraj T, Schilkey FD, Yukl ET. Zinc-Dependent Transcriptional Regulation in Paracoccus denitrificans. Front Microbiol 2017; 8:569. [PMID: 28443074 PMCID: PMC5387054 DOI: 10.3389/fmicb.2017.00569] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 03/20/2017] [Indexed: 01/20/2023] Open
Abstract
Zinc homeostasis is critical for bacterial survival and is mediated largely at the transcriptional level by the regulation of zinc uptake and efflux genes. Here we use RNA-seq to assess transcriptional changes as a result of zinc limitation in the denitrifying bacterium Paracoccus denitrificans. The results identify the differential expression of 147 genes, most of which were upregulated in zinc-depleted medium. Included in this set of genes are a large number of transition metal transporters, several transcription factors, and hypothetical proteins. Intriguingly, genes encoding nitric oxide reductase (norCB) and nitrite reductase (nirS) were also upregulated. A Zur consensus binding motif was identified in the promoters of the most highly upregulated genes. The zinc uptake regulator (Zur) from this organism was also characterized and shown to bind to the Zur motif in a zinc-dependent manner. This work expands our current understanding of the transcriptional response of gram-negative bacteria to zinc limitation and identifies genes involved in denitrification as part of the Zur regulon.
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Affiliation(s)
- Durga P Neupane
- Department of Chemistry and Biochemistry, New Mexico State UniversityLas Cruces, NM, USA
| | - Belkis Jacquez
- Department of Chemistry and Biochemistry, New Mexico State UniversityLas Cruces, NM, USA
| | | | | | | | - Erik T Yukl
- Department of Chemistry and Biochemistry, New Mexico State UniversityLas Cruces, NM, USA
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Lin J. Stress responses of Acinetobacter strain Y during phenol degradation. Arch Microbiol 2016; 199:365-375. [DOI: 10.1007/s00203-016-1310-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 08/10/2016] [Accepted: 10/17/2016] [Indexed: 12/14/2022]
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Neisseria gonorrhoeae Evades Calprotectin-Mediated Nutritional Immunity and Survives Neutrophil Extracellular Traps by Production of TdfH. Infect Immun 2016; 84:2982-94. [PMID: 27481245 DOI: 10.1128/iai.00319-16] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 07/25/2016] [Indexed: 12/19/2022] Open
Abstract
Neisseria gonorrhoeae successfully overcomes host strategies to limit essential nutrients, termed nutritional immunity, by production of TonB-dependent transporters (TdTs)-outer membrane proteins that facilitate nutrient transport in an energy-dependent manner. Four gonococcal TdTs facilitate utilization of iron or iron chelates from host-derived proteins, including transferrin (TbpA), lactoferrin (LbpA), and hemoglobin (HpuB), in addition to xenosiderophores from other bacteria (FetA). The roles of the remaining four uncharacterized TdTs (TdfF, TdfG, TdfH, and TdfJ) remain elusive. Regulatory data demonstrating that production of gonococcal TdfH and TdfJ are unresponsive to or upregulated under iron-replete conditions led us to evaluate the role of these TdTs in the acquisition of nutrients other than iron. In this study, we found that production of gonococcal TdfH is both Zn and Zur repressed. We also found that TdfH confers resistance to calprotectin, an immune effector protein highly produced in neutrophils that has antimicrobial activity due to its ability to sequester Zn and Mn. We found that TdfH directly binds calprotectin, which enables gonococcal Zn accumulation in a TdfH-dependent manner and enhances bacterial survival after exposure to neutrophil extracellular traps (NETs). These studies highlight Zn sequestration by calprotectin as a key functional arm of NET-mediated killing of gonococci. We demonstrate for the first time that N. gonorrhoeae exploits this host strategy in a novel defense mechanism, in which TdfH production hijacks and directly utilizes the host protein calprotectin as a zinc source and thereby evades nutritional immunity.
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Connor DO, Zantow J, Hust M, Bier FF, von Nickisch-Rosenegk M. Identification of Novel Immunogenic Proteins of Neisseria gonorrhoeae by Phage Display. PLoS One 2016; 11:e0148986. [PMID: 26859666 PMCID: PMC4747489 DOI: 10.1371/journal.pone.0148986] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 01/26/2016] [Indexed: 12/14/2022] Open
Abstract
Neisseria gonorrhoeae is one of the most prevalent sexually transmitted diseases worldwide with more than 100 million new infections per year. A lack of intense research over the last decades and increasing resistances to the recommended antibiotics call for a better understanding of gonococcal infection, fast diagnostics and therapeutic measures against N. gonorrhoeae. Therefore, the aim of this work was to identify novel immunogenic proteins as a first step to advance those unresolved problems. For the identification of immunogenic proteins, pHORF oligopeptide phage display libraries of the entire N. gonorrhoeae genome were constructed. Several immunogenic oligopeptides were identified using polyclonal rabbit antibodies against N. gonorrhoeae. Corresponding full-length proteins of the identified oligopeptides were expressed and their immunogenic character was verified by ELISA. The immunogenic character of six proteins was identified for the first time. Additional 13 proteins were verified as immunogenic proteins in N. gonorrhoeae.
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Affiliation(s)
- Daniel O. Connor
- Department of Bioanalytics and Biosensorics, Fraunhofer Institute for Cell Therapy and Immunology, Branch Bioanalytics and Bioprocesses (IZI-BB), Potsdam, Germany
| | - Jonas Zantow
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Michael Hust
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Frank F. Bier
- Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
- Department of Biosystem Integration and Automation, Fraunhofer Institute for Cell Therapy and Immunology, Branch Bioanalytics and Bioprocesses (IZI-BB), Potsdam, Germany
| | - Markus von Nickisch-Rosenegk
- Department of Bioanalytics and Biosensorics, Fraunhofer Institute for Cell Therapy and Immunology, Branch Bioanalytics and Bioprocesses (IZI-BB), Potsdam, Germany
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Spohn M, Wohlleben W, Stegmann E. Elucidation of the zinc-dependent regulation inAmycolatopsis japonicumenabled the identification of the ethylenediamine-disuccinate ([S,S]-EDDS) genes. Environ Microbiol 2016; 18:1249-63. [DOI: 10.1111/1462-2920.13159] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 11/13/2015] [Accepted: 11/27/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Marius Spohn
- Interfaculty Institute of Microbiology and Infection Medicine Tuebingen, Microbiology/Biotechnology; University of Tuebingen; 72076 Tuebingen Germany
| | - Wolfgang Wohlleben
- Interfaculty Institute of Microbiology and Infection Medicine Tuebingen, Microbiology/Biotechnology; University of Tuebingen; 72076 Tuebingen Germany
- Partner Site Tuebingen; German Centre for Infection Research (DZIF); Tuebingen Germany
| | - Evi Stegmann
- Interfaculty Institute of Microbiology and Infection Medicine Tuebingen, Microbiology/Biotechnology; University of Tuebingen; 72076 Tuebingen Germany
- Partner Site Tuebingen; German Centre for Infection Research (DZIF); Tuebingen Germany
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HexR Controls Glucose-Responsive Genes and Central Carbon Metabolism in Neisseria meningitidis. J Bacteriol 2015; 198:644-54. [PMID: 26644430 DOI: 10.1128/jb.00659-15] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 11/24/2015] [Indexed: 12/29/2022] Open
Abstract
UNLABELLED Neisseria meningitidis, an exclusively human pathogen and the leading cause of bacterial meningitis, must adapt to different host niches during human infection. N. meningitidis can utilize a restricted range of carbon sources, including lactate, glucose, and pyruvate, whose concentrations vary in host niches. Microarray analysis of N. meningitidis grown in a chemically defined medium in the presence or absence of glucose allowed us to identify genes regulated by carbon source availability. Most such genes are implicated in energy metabolism and transport, and some are implicated in virulence. In particular, genes involved in glucose catabolism were upregulated, whereas genes involved in the tricarboxylic acid cycle were downregulated. Several genes encoding surface-exposed proteins, including the MafA adhesins and Neisseria surface protein A, were upregulated in the presence of glucose. Our microarray analysis led to the identification of a glucose-responsive hexR-like transcriptional regulator that controls genes of the central carbon metabolism of N. meningitidis in response to glucose. We characterized the HexR regulon and showed that the hexR gene is accountable for some of the glucose-responsive regulation; in vitro assays with the purified protein showed that HexR binds to the promoters of the central metabolic operons of the bacterium. Based on DNA sequence alignment of the target sites, we propose a 17-bp pseudopalindromic consensus HexR binding motif. Furthermore, N. meningitidis strains lacking hexR expression were deficient in establishing successful bacteremia in an infant rat model of infection, indicating the importance of this regulator for the survival of this pathogen in vivo. IMPORTANCE Neisseria meningitidis grows on a limited range of nutrients during infection. We analyzed the gene expression of N. meningitidis in response to glucose, the main energy source available in human blood, and we found that glucose regulates many genes implicated in energy metabolism and nutrient transport, as well as some implicated in virulence. We identified and characterized a transcriptional regulator (HexR) that controls metabolic genes of N. meningitidis in response to glucose. We generated a mutant lacking HexR and found that the mutant was impaired in causing systemic infection in animal models. Since N. meningitidis lacks known bacterial regulators of energy metabolism, our findings suggest that HexR plays a major role in its biology by regulating metabolism in response to environmental signals.
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Calmettes C, Ing C, Buckwalter CM, El Bakkouri M, Chieh-Lin Lai C, Pogoutse A, Gray-Owen SD, Pomès R, Moraes TF. The molecular mechanism of Zinc acquisition by the neisserial outer-membrane transporter ZnuD. Nat Commun 2015; 6:7996. [PMID: 26282243 PMCID: PMC4557270 DOI: 10.1038/ncomms8996] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 07/03/2015] [Indexed: 11/09/2022] Open
Abstract
Invading bacteria from the Neisseriaceae, Acinetobacteriaceae, Bordetellaceae and Moraxellaceae families express the conserved outer-membrane zinc transporter zinc-uptake component D (ZnuD) to overcome nutritional restriction imposed by the host organism during infection. Here we demonstrate that ZnuD is required for efficient systemic infections by the causative agent of bacterial meningitis, Neisseria meningitidis, in a mouse model. We also combine X-ray crystallography and molecular dynamics simulations to gain insight into the mechanism of zinc recognition and transport across the bacterial outer-membrane by ZnuD. Because ZnuD is also considered a promising vaccine candidate against N. meningitidis, we use several ZnuD structural intermediates to map potential antigenic epitopes, and propose a mechanism by which ZnuD can maintain high sequence conservation yet avoid immune recognition by altering the conformation of surface-exposed loops. ZnuD is a conserved zinc transporter expressed in several bacterial pathogens with potential as a target against infection. Here the authors demonstrate a requirement for ZnuD in systemic infection by N. meningitidis and define the molecular mechanism of ZnuD-mediated Zinc transport across the bacterial outer membrane.
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Affiliation(s)
- Charles Calmettes
- Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Christopher Ing
- 1] Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada [2] Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
| | - Carolyn M Buckwalter
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Majida El Bakkouri
- Structural Genomic Consortium, University of Toronto, Toronto, Ontario M5G 1L7, Canada
| | - Christine Chieh-Lin Lai
- Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Anastassia Pogoutse
- Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Scott D Gray-Owen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Régis Pomès
- 1] Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada [2] Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
| | - Trevor F Moraes
- Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
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Prisic S, Hwang H, Dow A, Barnaby O, Pan TS, Lonzanida JA, Chazin WJ, Steen H, Husson RN. Zinc regulates a switch between primary and alternative S18 ribosomal proteins in Mycobacterium tuberculosis. Mol Microbiol 2015; 97:263-80. [PMID: 25858183 DOI: 10.1111/mmi.13022] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/02/2015] [Indexed: 12/21/2022]
Abstract
The Mycobacterium tuberculosis genome encodes five putative 'alternative' ribosomal proteins whose expression is repressed at high Zn(2+) concentration. Each alternative protein has a primary homologue that is predicted to bind Zn(2+). We hypothesized that zinc triggers a switch between these paired homologous proteins and therefore chose one of these pairs, S18-1/S18-2, to study mechanisms of the predicted competition for their incorporation into ribosomes. Our data show that Zn(2+)-depletion causes accumulation of both S18-2 mRNA and protein. In contrast, S18-1 mRNA levels are unchanged to slightly elevated under Zn(2+)-limited conditions. However, the amount of S18-1 protein is markedly decreased. We further demonstrate that both S18 proteins interact with ribosomal protein S6, a committed step in ribosome biogenesis. Zn(2+) is absolutely required for the S18-1/S6 interaction while it is dispensable for S18-2/S6 dimer formation. These data suggest a model in which S18-1 is the dominant ribosome constituent in high zinc conditions, e.g. inside of phagosomes, but that it can be replaced by S18-2 when zinc is deficient, e.g. in the extracellular milieu. Consequently, Zn(2+)-depletion may serve as a signal for building alternative ribosomes when M. tuberculosis is released from macrophages, to allow survival in the extracellular environment.
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Affiliation(s)
- Sladjana Prisic
- Division of Infectious Diseases, Boston Children's Hospital/Harvard Medical School, Boston, MA.,Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI
| | - Hyonson Hwang
- Department of Pathology, Boston Children's Hospital/Harvard Medical School, Boston, MA
| | - Allexa Dow
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI
| | - Omar Barnaby
- Department of Pathology, Boston Children's Hospital/Harvard Medical School, Boston, MA
| | - Tenny S Pan
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI
| | | | - Walter J Chazin
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Hanno Steen
- Department of Pathology, Boston Children's Hospital/Harvard Medical School, Boston, MA
| | - Robert N Husson
- Division of Infectious Diseases, Boston Children's Hospital/Harvard Medical School, Boston, MA
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Cerasi M, Liu JZ, Ammendola S, Poe AJ, Petrarca P, Pesciaroli M, Pasquali P, Raffatellu M, Battistoni A. The ZupT transporter plays an important role in zinc homeostasis and contributes to Salmonella enterica virulence. Metallomics 2014; 6:845-53. [PMID: 24430377 DOI: 10.1039/c3mt00352c] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Zinc is an essential metal for cellular homeostasis and function in both eukaryotes and prokaryotes. To acquire this essential nutrient, bacteria employ transporters characterized by different affinity for the metal. Several studies have investigated the role of the high affinity transporter ZnuABC in the bacterial response to zinc shortage, showing that this transporter has a key role in adapting bacteria to zinc starvation. In contrast, the role of the low affinity zinc importer ZupT has been the subject of limited investigations. Here we show that a Salmonella strain lacking ZupT is impaired in its ability to grow in metal devoid environments and that a znuABC zupT strain exhibits a severe growth defect in zinc devoid media, is hypersensitive to oxidative stress and contains reduced levels of intracellular free zinc. Moreover, we show that ZupT also plays a role in the ability of S. Typhimurium to colonize the host tissues. During systemic infections, the single zupT mutant strain was attenuated only in Nramp1(+/+) mice, but competition experiments between znuABC and znuABC zupT mutants revealed that ZupT contributes to metal uptake in vivo independently of the presence of a functional Nramp1 transporter. Altogether, the here reported results show that ZupT plays an important role in Salmonella zinc homeostasis, being involved in metal import both in vitro and in infected animals.
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Affiliation(s)
- Mauro Cerasi
- Dipartimento di Biologia, Università di Roma Tor Vergata, Via della Ricerca Scientifica, 00133 Rome, Italy.
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Gilston BA, Wang S, Marcus MD, Canalizo-Hernández MA, Swindell EP, Xue Y, Mondragón A, O'Halloran TV. Structural and mechanistic basis of zinc regulation across the E. coli Zur regulon. PLoS Biol 2014; 12:e1001987. [PMID: 25369000 PMCID: PMC4219657 DOI: 10.1371/journal.pbio.1001987] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 09/22/2014] [Indexed: 11/18/2022] Open
Abstract
Structural, thermodynamic, and gene expression studies provide a comprehensive picture of how the bacterial metalloregulatory transcriptional repressor Zur achieves its exquisite sensitivity to zinc concentrations. Commensal microbes, whether they are beneficial or pathogenic, are sensitive to host processes that starve or swamp the prokaryote with large fluctuations in local zinc concentration. To understand how microorganisms coordinate a dynamic response to changes in zinc availability at the molecular level, we evaluated the molecular mechanism of the zinc-sensing zinc uptake regulator (Zur) protein at each of the known Zur-regulated genes in Escherichia coli. We solved the structure of zinc-loaded Zur bound to the PznuABC promoter and show that this metalloregulatory protein represses gene expression by a highly cooperative binding of two adjacent dimers to essentially encircle the core element of each of the Zur-regulated promoters. Cooperativity in these protein-DNA interactions requires a pair of asymmetric salt bridges between Arg52 and Asp49′ that connect otherwise independent dimers. Analysis of the protein-DNA interface led to the discovery of a new member of the Zur-regulon: pliG. We demonstrate this gene is directly regulated by Zur in a zinc responsive manner. The pliG promoter forms stable complexes with either one or two Zur dimers with significantly less protein-DNA cooperativity than observed at other Zur regulon promoters. Comparison of the in vitro Zur-DNA binding affinity at each of four Zur-regulon promoters reveals ca. 10,000-fold variation Zur-DNA binding constants. The degree of Zur repression observed in vivo by comparison of transcript copy number in wild-type and Δzur strains parallels this trend spanning a 100-fold difference. We conclude that the number of ferric uptake regulator (Fur)-family dimers that bind within any given promoter varies significantly and that the thermodynamic profile of the Zur-DNA interactions directly correlates with the physiological response at different promoters. Zinc is an essential nutrient for most organisms, with the Zn2+ ion performing numerous structural, regulatory, and catalytic roles in a range of proteins. However, this nutrient can neither be synthesized nor degraded and individual cells need to be able to maintain steady levels of zinc in the face of near-zero or excessively high environmental concentrations. Here we look at how the bacterium E. coli does this, by examining the structure and function of Zur, a transcriptional repressor that is exquisitely sensitive to Zn2+ concentration. Although the structures of related Zur proteins on their own are known, here we show how E. coli protein binds to DNA and explain its extreme sensitivity and specificity (it responds to Zn2+ concentrations in the femtomolar range). Our results reveal how the Zur protein switches on and off a bank of bacterial genes that control zinc physiology. Extensive analysis of protein-DNA interactions revealed both a surprising degree of cooperativity and an extremely large range of Zur-DNA binding affinities across the set of genes known as the Zur regulon. The results provide strong support for a controversial idea that the thermodynamics of an ensemble of protein-DNA interactions play a dominant role in the physiological control of gene regulation networks. In addition, we have used our structural and thermodynamic analysis to identify a novel gene target of Zur regulation.
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Affiliation(s)
- Benjamin A. Gilston
- Department of Chemistry and The Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois, United States of America
| | - Suning Wang
- Department of Chemistry and The Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois, United States of America
| | - Mason D. Marcus
- Department of Chemistry and The Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois, United States of America
| | - Mónica A. Canalizo-Hernández
- Department of Chemistry and The Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois, United States of America
| | - Elden P. Swindell
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois, United States of America
| | - Yi Xue
- Department of Chemistry and The Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois, United States of America
| | - Alfonso Mondragón
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
- * E-mail: (AM); (TVO)
| | - Thomas V. O'Halloran
- Department of Chemistry and The Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois, United States of America
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
- * E-mail: (AM); (TVO)
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Becker KW, Skaar EP. Metal limitation and toxicity at the interface between host and pathogen. FEMS Microbiol Rev 2014; 38:1235-49. [PMID: 25211180 DOI: 10.1111/1574-6976.12087] [Citation(s) in RCA: 171] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2014] [Revised: 08/09/2014] [Accepted: 08/31/2014] [Indexed: 12/14/2022] Open
Abstract
Metals are required cofactors for numerous fundamental processes that are essential to both pathogen and host. They are coordinated in enzymes responsible for DNA replication and transcription, relief from oxidative stress, and cellular respiration. However, excess transition metals can be toxic due to their ability to cause spontaneous, redox cycling and disrupt normal metabolic processes. Vertebrates have evolved intricate mechanisms to limit the availability of some crucial metals while concurrently flooding sites of infection with antimicrobial concentrations of other metals. To compete for limited metal within the host while simultaneously preventing metal toxicity, pathogens have developed a series of metal regulatory, acquisition, and efflux systems. This review will cover the mechanisms by which pathogenic bacteria recognize and respond to host-induced metal scarcity and toxicity.
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Affiliation(s)
- Kyle W Becker
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
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Mazzon RR, Braz VS, da Silva Neto JF, do Valle Marques M. Analysis of the Caulobacter crescentus Zur regulon reveals novel insights in zinc acquisition by TonB-dependent outer membrane proteins. BMC Genomics 2014; 15:734. [PMID: 25168179 PMCID: PMC4176598 DOI: 10.1186/1471-2164-15-734] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 08/21/2014] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Intracellular zinc concentration needs to be maintained within strict limits due to its toxicity at high levels, and this is achieved by a finely regulated balance between uptake and efflux. Many bacteria use the Zinc Uptake Regulator Zur to orchestrate zinc homeostasis, but little is known regarding the transport of this metal across the bacterial outer membrane. RESULTS In this work we determined the Caulobacter crescentus Zur regulon by global transcriptional and in silico analyses. Among the genes directly repressed by Zur in response to zinc availability are those encoding a putative high affinity ABC uptake system (znuGHI), three TonB-dependent receptors (znuK, znuL and znuM) and one new putative transporter of a family not yet characterized (zrpW). Zur is also directly involved in the activation of a RND and a P-type ATPase efflux systems, as revealed by β-galactosidase and site-directed mutagenesis assays. Several genes belonging to the Fur regulon were also downregulated in the zur mutant, suggesting a putative cross-talk between Zur and Fur regulatory networks. Interestingly, a phenotypic analysis of the znuK and znuL mutants has shown that these genes are essential for growth under zinc starvation, suggesting that C. crescentus uses these TonB-dependent outer membrane transporters as key zinc scavenging systems. CONCLUSIONS The characterization of the C. crescentus Zur regulon showed that this regulator coordinates not only uptake, but also the extrusion of zinc. The uptake of zinc by C. crescentus in conditions of scarcity of this metal is highly dependent on TonB-dependent receptors, and the extrusion is mediated by an RND and P-type ATPase transport systems. The absence of Zur causes a disturbance in the dynamic equilibrium of zinc intracellular concentration, which in turn can interfere with other regulatory networks as seen for the Fur regulon.
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Affiliation(s)
| | | | | | - Marilis do Valle Marques
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av, Prof, Lineu Prestes 1374, 05508-900 São Paulo, Brazil.
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Choi S, Bird AJ. Zinc'ing sensibly: controlling zinc homeostasis at the transcriptional level. Metallomics 2014; 6:1198-215. [PMID: 24722954 DOI: 10.1039/c4mt00064a] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Zinc-responsive transcription factors are found in all kingdoms of life and include the transcriptional activators ZntR, SczA, Zap1, bZip19, bZip23, and MTF-1, and transcriptional repressors Zur, AdcR, Loz1, and SmtB. These factors have two defining features; their activity is regulated by zinc and they all play a central role in zinc homeostasis by controlling the expression of genes that directly affect zinc levels or its availability. This review summarizes what is known about the mechanisms by which each of these factors sense changes in intracellular zinc levels and how they control zinc homeostasis through target gene regulation. Other factors that influence zinc ion sensing are also discussed.
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Affiliation(s)
- Sangyong Choi
- Department of Human Sciences, The Ohio State University, Columbus, OH 43210, USA
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Acinetobacter baumannii response to host-mediated zinc limitation requires the transcriptional regulator Zur. J Bacteriol 2014; 196:2616-26. [PMID: 24816603 DOI: 10.1128/jb.01650-14] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Acinetobacter baumannii is a leading cause of ventilator-associated pneumonia in intensive care units, and the increasing rates of antibiotic resistance make treating these infections challenging. Consequently, there is an urgent need to develop new antimicrobials to treat A. baumannii infections. One potential therapeutic option is to target bacterial systems involved in maintaining appropriate metal homeostasis, processes that are critical for the growth of pathogens within the host. The A. baumannii inner membrane zinc transporter ZnuABC is required for growth under low-zinc conditions and for A. baumannii pathogenesis. The expression of znuABC is regulated by the transcriptional repressor Zur. To investigate the role of Zur during the A. baumannii response to zinc limitation, a zur deletion mutant was generated, and transcriptional changes were analyzed using RNA sequencing. A number of Zur-regulated genes were identified that exhibit increased expression both when zur is absent and under low-zinc conditions, and Zur binds to predicted Zur box sequences of several genes affected by zinc levels or the zur mutation. Furthermore, the zur mutant is impaired for growth in the presence of both high and low zinc levels compared to wild-type A. baumannii. Finally, the zur mutant exhibits a defect in dissemination in a mouse model of A. baumannii pneumonia, establishing zinc sensing as a critical process during A. baumannii infection. These results define Zur-regulated genes within A. baumannii and demonstrate a requirement for Zur in the A. baumannii response to the various zinc levels experienced within the vertebrate host.
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Quantification by LC–MSE of outer membrane vesicle proteins of the Bexsero® vaccine. Vaccine 2014; 32:1273-9. [DOI: 10.1016/j.vaccine.2014.01.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 12/09/2013] [Accepted: 01/02/2014] [Indexed: 01/24/2023]
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Fillat MF. The FUR (ferric uptake regulator) superfamily: diversity and versatility of key transcriptional regulators. Arch Biochem Biophys 2014; 546:41-52. [PMID: 24513162 DOI: 10.1016/j.abb.2014.01.029] [Citation(s) in RCA: 217] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 01/27/2014] [Accepted: 01/31/2014] [Indexed: 11/17/2022]
Abstract
Control of metal homeostasis is essential for life in all kingdoms. In most prokaryotic organisms the FUR (ferric uptake regulator) family of transcriptional regulators is involved in the regulation of iron and zinc metabolism through control by Fur and Zur proteins. A third member of this family, the peroxide-stress response PerR, is present in most Gram-positives, establishing a tight functional interaction with the global regulator Fur. These proteins play a pivotal role for microbial survival under adverse conditions and in the expression of virulence in most pathogens. In this paper we present the current state of the art in the knowledge of the FUR family, including those members only present in more reduced numbers of bacteria, namely Mur, Nur and Irr. The huge amount of work done in the two last decades shows that FUR proteins present considerable diversity in their regulatory mechanisms and interesting structural differences. However, much work needs to be done to obtain a more complete picture of this family, especially in connection with the roles of some members as gas and redox sensors as well as to fully characterize their participation in bacterial adaptative responses.
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Affiliation(s)
- María F Fillat
- Department of Biochemistry and Molecular and Cell Biology, Institute for Biocomputation and Physics of Complex Systems (BIFI), University of Zaragoza, Pedro Cerbuna, 12, 50009 Zaragoza, Spain.
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Cerasi M, Ammendola S, Battistoni A. Competition for zinc binding in the host-pathogen interaction. Front Cell Infect Microbiol 2013; 3:108. [PMID: 24400228 PMCID: PMC3872050 DOI: 10.3389/fcimb.2013.00108] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 12/11/2013] [Indexed: 11/13/2022] Open
Abstract
Due to its favorable chemical properties, zinc is used as a structural or catalytic cofactor in a very large number of proteins. Despite the apparent abundance of this metal in all cell types, the intracellular pool of loosely bound zinc ions available for biological exchanges is in the picomolar range and nearly all zinc is tightly bound to proteins. In addition, to limit bacterial growth, some zinc-sequestering proteins are produced by eukaryotic hosts in response to infections. Therefore, to grow and multiply in the infected host, bacterial pathogens must produce high affinity zinc importers, such as the ZnuABC transporter which is present in most Gram-negative bacteria. Studies carried in different bacterial species have established that disruption of ZnuABC is usually associated with a remarkable loss of pathogenicity. The critical involvement of zinc in a plethora of metabolic and virulence pathways and the presence of very low number of zinc importers in most bacterial species mark zinc homeostasis as a very promising target for the development of novel antimicrobial strategies.
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Affiliation(s)
- Mauro Cerasi
- Dipartimento di Biologia, Università di Roma Tor Vergata Rome, Italy
| | - Serena Ammendola
- Dipartimento di Biologia, Università di Roma Tor Vergata Rome, Italy
| | - Andrea Battistoni
- Dipartimento di Biologia, Università di Roma Tor Vergata Rome, Italy ; Istituto Nazionale Biostrutture e Biosistemi, Consorzio Interuniversitario Rome, Italy
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Mortensen BL, Skaar EP. The contribution of nutrient metal acquisition and metabolism to Acinetobacter baumannii survival within the host. Front Cell Infect Microbiol 2013; 3:95. [PMID: 24377089 PMCID: PMC3859900 DOI: 10.3389/fcimb.2013.00095] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 11/21/2013] [Indexed: 01/12/2023] Open
Abstract
Acinetobacter baumannii is a significant contributor to intensive care unit (ICU) mortality causing numerous types of infection in this susceptible ICU population, most notably ventilator-associated pneumonia. The substantial disease burden attributed to A. baumannii and the rapid acquisition of antibiotic resistance make this bacterium a serious health care threat. A. baumannii is equipped to tolerate the hostile host environment through modification of its metabolism and nutritional needs. Among these adaptations is the evolution of mechanisms to acquire nutrient metals that are sequestered by the host as a defense against infection. Although all bacteria require nutrient metals, there is diversity in the particular metal needs among species and within varying tissue types and bacterial lifecycles. A. baumannii is well-equipped with the metal homeostatic systems required for the colonization of a diverse array of tissues. Specifically, iron and zinc homeostasis is important for A. baumannii interactions with biotic surfaces and for growth within vertebrates. This review discusses what is currently known regarding the interaction of A. baumannii with vertebrate cells with a particular emphasis on the contributions of metal homeostasis systems. Overall, published research supports the utility of exploiting these systems as targets for the development of much-needed antimicrobials against this emerging infectious threat.
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Affiliation(s)
- Brittany L Mortensen
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine Nashville, TN, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine Nashville, TN, USA
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Zinc piracy as a mechanism of Neisseria meningitidis for evasion of nutritional immunity. PLoS Pathog 2013; 9:e1003733. [PMID: 24204275 PMCID: PMC3814407 DOI: 10.1371/journal.ppat.1003733] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 09/13/2013] [Indexed: 11/19/2022] Open
Abstract
The outer membrane of Gram-negative bacteria functions as a permeability barrier that protects these bacteria against harmful compounds in the environment. Most nutrients pass the outer membrane by passive diffusion via pore-forming proteins known as porins. However, diffusion can only satisfy the growth requirements if the extracellular concentration of the nutrients is high. In the vertebrate host, the sequestration of essential nutrient metals is an important defense mechanism that limits the growth of invading pathogens, a process known as “nutritional immunity.” The acquisition of scarce nutrients from the environment is mediated by receptors in the outer membrane in an energy-requiring process. Most characterized receptors are involved in the acquisition of iron. In this study, we characterized a hitherto unknown receptor from Neisseria meningitidis, a causative agent of sepsis and meningitis. Expression of this receptor, designated CbpA, is induced when the bacteria are grown under zinc limitation. We demonstrate that CbpA functions as a receptor for calprotectin, a protein that is massively produced by neutrophils and other cells and that has been shown to limit bacterial growth by chelating Zn2+ and Mn2+ ions. Expression of CbpA enables N. meningitidis to survive and propagate in the presence of calprotectin and to use calprotectin as a zinc source. Besides CbpA, also the TonB protein, which couples energy of the proton gradient across the inner membrane to receptor-mediated transport across the outer membrane, is required for the process. CbpA was found to be expressed in all N. meningitidis strains examined, consistent with a vital role for the protein when the bacteria reside in the host. Together, our results demonstrate that N. meningitidis is able to subvert an important defense mechanism of the human host and to utilize calprotectin to promote its growth. The sequestration of essential nutrient metals is a first line of defense used by vertebrates to limit the growth of invading pathogens, a process termed “nutritional immunity.” As a part of this defense mechanism, neutrophils and other cells produce massive amounts of calprotectin, a protein that limits bacterial growth by chelating Zn2+ and Mn2+ ions. We demonstrate here that Neisseria meningitidis, a resident of the human nasopharynx that occasionally causes sepsis and meningitis, is able to survive and propagate in the presence of calprotectin. N. meningitidis responds to zinc limitation by the overproduction of an outer membrane protein, called CbpA, that functions as a receptor for calprotectin and enables the bacteria to utilize calprotectin as zinc source. The ability of N. meningitidis to use calprotectin as a zinc source subverts an important defense mechanism of the host and adds a new mechanism to the host-pathogens arms race.
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