1
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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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Goh KGK, Desai D, Thapa R, Prince D, Acharya D, Sullivan MJ, Ulett GC. An opportunistic pathogen under stress: how Group B Streptococcus responds to cytotoxic reactive species and conditions of metal ion imbalance to survive. FEMS Microbiol Rev 2024; 48:fuae009. [PMID: 38678005 PMCID: PMC11098048 DOI: 10.1093/femsre/fuae009] [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: 08/31/2023] [Revised: 03/26/2024] [Accepted: 04/16/2024] [Indexed: 04/29/2024] Open
Abstract
Group B Streptococcus (GBS; also known as Streptococcus agalactiae) is an opportunistic bacterial pathogen that causes sepsis, meningitis, pneumonia, and skin and soft tissue infections in neonates and healthy or immunocompromised adults. GBS is well-adapted to survive in humans due to a plethora of virulence mechanisms that afford responses to support bacterial survival in dynamic host environments. These mechanisms and responses include counteraction of cell death from exposure to excess metal ions that can cause mismetallation and cytotoxicity, and strategies to combat molecules such as reactive oxygen and nitrogen species that are generated as part of innate host defence. Cytotoxicity from reactive molecules can stem from damage to proteins, DNA, and membrane lipids, potentially leading to bacterial cell death inside phagocytic cells or within extracellular spaces within the host. Deciphering the ways in which GBS responds to the stress of cytotoxic reactive molecules within the host will benefit the development of novel therapeutic and preventative strategies to manage the burden of GBS disease. This review summarizes knowledge of GBS carriage in humans and the mechanisms used by the bacteria to circumvent killing by these important elements of host immune defence: oxidative stress, nitrosative stress, and stress from metal ion intoxication/mismetallation.
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Affiliation(s)
- Kelvin G K Goh
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
| | - Devika Desai
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
| | - Ruby Thapa
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
| | - Darren Prince
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
| | - Dhruba Acharya
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
| | - Matthew J Sullivan
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, United Kingdom
| | - Glen C Ulett
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
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3
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De Lay NR, Verma N, Sinha D, Garrett A, Osterberg MK, Reiling S, Porter D, Giedroc DP, Winkler ME. The five homologous CiaR-controlled Ccn sRNAs of Streptococcus pneumoniae modulate Zn-resistance. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.07.565944. [PMID: 37986909 PMCID: PMC10659304 DOI: 10.1101/2023.11.07.565944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Zinc is a vital transition metal for Streptococcus pneumoniae, but is deadly at high concentrations. In S. pneumoniae, elevated intracellular free Zn levels result in mis-metallation of key Mn-dependent metabolic and superoxide detoxifying enzymes resulting in Zn intoxication. Here, we report our identification and characterization of the function of the five homologous, CiaRH-regulated Ccn sRNAs in controlling S. pneumoniae virulence and metal homeostasis. We show that deletion of all five ccn genes (ccnA, ccnB, ccnC, ccnD, and ccnE) from S. pneumoniae strains D39 (serotype 2) and TIGR4 (serotype 4) causes Zn hypersensitivity and an attenuation of virulence in a murine invasive pneumonia model. We provide evidence that bioavailable Zn disproportionately increases in S. pneumoniae strains lacking the five ccn genes. Consistent with a response to Zn intoxication or relatively high intracellular free Zn levels, expression of genes encoding the CzcD Zn exporter and the Mn-independent ribonucleotide reductase, NrdD-NrdG, were increased in the ΔccnABCDE mutant relative to its isogenic ccn+ parent strain. The growth inhibition by Zn that occurs as the result of loss of the ccn genes is rescued by supplementation with Mn or Oxyrase™, a reagent that removes dissolved oxygen. Lastly, we found that the Zn-dependent growth inhibition of the ΔccnABCDE strain was not altered by deletion of sodA, whereas the ccn+ ΔsodA strain phenocopied the ΔccnABCDE strain. Overall, our results indicate that the Ccn sRNAs have a crucial role in preventing Zn intoxication in S. pneumoniae.
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Affiliation(s)
- Nicholas R. De Lay
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Nidhi Verma
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Dhriti Sinha
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Abigail Garrett
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana 47405
| | | | - Spencer Reiling
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Daisy Porter
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - David P. Giedroc
- Department of Chemistry, Indiana University, Bloomington, Bloomington, Indiana 47405
| | - Malcolm E. Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana 47405
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4
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Xu X, Zhang L, Cui Y, Kong J, Guo T. Development of Zn 2+-controlled expression system for lactic acid bacteria and its application in engineered probiotics. Synth Syst Biotechnol 2024; 9:152-158. [PMID: 38328736 PMCID: PMC10847839 DOI: 10.1016/j.synbio.2024.01.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 01/04/2024] [Accepted: 01/22/2024] [Indexed: 02/09/2024] Open
Abstract
Lactococcus lactis and Streptococcus thermophilus are considered as ideal chassis of engineered probiotics, while food-grade genetic tools are limited in those strains. Here, a Zn2+-controlled gene expression (ZICE) system was identified in the genome of S. thermophilus CGMCC7.179, including a transcriptional regulator sczAst and a promoter region of cation transporter czcD (PczcDst). Specific binding of the SczAst to the palindromic sequences in PczcDst was demonstrated by EMSA analysis, suggesting the regulation role of SczAst on PczcDst. To evaluate their possibility to control gene expression in vivo, the sczAst-PczcDst was employed to drive the expression of green fluorescence protein (GFP) gene in L. lactis NZ9000 and S. thermophilus CGMCC7.179, respectively. Both of the transformants could express GFP under Zn2+ induction, while no fluorescence without Zn2+ addition. For optimal conditions, Zn2+ was used at a final concentration of 0.8 mM in L. lactis and 0.16 mM in S. thermophilus at OD600 close to 0.4, and omitting yeast extract powder in the medium unexpectedly improved GFP expression level by 2.2-fold. With the help of the ZICE system, engineered L. lactis and S. thermophilus strains were constructed to secret cytokine interleukin-10 (IL-10) with immunogenicity, and the IL-10 content in the supernatant of the engineered L. lactis was 59.37 % of that under the nisin controlled expression system. This study provided a tightly controlled expression system by the food-grade inducer Zn2+, having potential in development of engineered probiotics.
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Affiliation(s)
| | | | - Yue Cui
- State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao, 266237, PR China
| | - Jian Kong
- State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao, 266237, PR China
| | - Tingting Guo
- State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao, 266237, PR China
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5
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Yu L, Xu X, Chua WZ, Feng H, Ser Z, Shao K, Shi J, Wang Y, Li Z, Sobota RM, Sham LT, Luo M. Structural basis of peptide secretion for Quorum sensing by ComA. Nat Commun 2023; 14:7178. [PMID: 37935699 PMCID: PMC10630487 DOI: 10.1038/s41467-023-42852-9] [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: 04/12/2023] [Accepted: 10/23/2023] [Indexed: 11/09/2023] Open
Abstract
Quorum sensing (QS) is a crucial regulatory mechanism controlling bacterial signalling and holds promise for novel therapies against antimicrobial resistance. In Gram-positive bacteria, such as Streptococcus pneumoniae, ComA is a conserved efflux pump responsible for the maturation and secretion of peptide signals, including the competence-stimulating peptide (CSP), yet its structure and function remain unclear. Here, we functionally characterize ComA as an ABC transporter with high ATP affinity and determined its cryo-EM structures in the presence or absence of CSP or nucleotides. Our findings reveal a network of strong electrostatic interactions unique to ComA at the intracellular gate, a putative binding pocket for two CSP molecules, and negatively charged residues facilitating CSP translocation. Mutations of these residues affect ComA's peptidase activity in-vitro and prevent CSP export in-vivo. We demonstrate that ATP-Mg2+ triggers the outward-facing conformation of ComA for CSP release, rather than ATP alone. Our study provides molecular insights into the QS signal peptide secretion, highlighting potential targets for QS-targeting drugs.
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Affiliation(s)
- Lin Yu
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
- Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou, 225001, Jiangsu, China
| | - Xin Xu
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
| | - Wan-Zhen Chua
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545, Singapore
| | - Hao Feng
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
| | - Zheng Ser
- Functional Proteomics Laboratory, SingMass National Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, 138673, Singapore
| | - Kai Shao
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
| | - Jian Shi
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
- Center for Bioimaging Sciences, Department of Biological Sciences, National University of Singapore, Singapore, 117543, Singapore
| | - Yumei Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing, 100190, China
| | - Zongli Li
- Harvard Cryo-EM Center for Structural Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Radoslaw M Sobota
- Functional Proteomics Laboratory, SingMass National Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, 138673, Singapore
| | - Lok-To Sham
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545, Singapore.
| | - Min Luo
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore.
- Center for Bioimaging Sciences, Department of Biological Sciences, National University of Singapore, Singapore, 117543, Singapore.
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6
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Tsui HCT, Joseph M, Zheng JJ, Perez AJ, Manzoor I, Rued BE, Richardson JD, Branny P, Doubravová L, Massidda O, Winkler ME. Negative regulation of MurZ and MurA underlies the essentiality of GpsB- and StkP-mediated protein phosphorylation in Streptococcus pneumoniae D39. Mol Microbiol 2023; 120:351-383. [PMID: 37452010 PMCID: PMC10530524 DOI: 10.1111/mmi.15122] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 06/27/2023] [Accepted: 06/28/2023] [Indexed: 07/18/2023]
Abstract
GpsB links peptidoglycan synthases to other proteins that determine the shape of the respiratory pathogen Streptococcus pneumoniae (pneumococcus; Spn) and other low-GC Gram-positive bacteria. GpsB is also required for phosphorylation of proteins by the essential StkP(Spn) Ser/Thr protein kinase. Here we report three classes of frequently arising chromosomal duplications (≈21-176 genes) containing murZ (MurZ-family homolog of MurA) or murA that suppress ΔgpsB or ΔstkP. These duplications arose from three different repeated sequences and demonstrate the facility of pneumococcus to modulate gene dosage of numerous genes. Overproduction of MurZ or MurA alone or overproduction of MurZ caused by ΔkhpAB mutations suppressed ΔgpsB or ΔstkP phenotypes to varying extents. ΔgpsB and ΔstkP were also suppressed by MurZ amino-acid changes distant from the active site, including one in commonly studied laboratory strains, and by truncation or deletion of the homolog of IreB(ReoM). Unlike in other Gram-positive bacteria, MurZ is predominant to MurA in pneumococcal cells. However, ΔgpsB and ΔstkP were not suppressed by ΔclpCP, which did not alter MurZ or MurA amounts. These results support a model in which regulation of MurZ and MurA activity, likely by IreB(Spn), is the only essential requirement for StkP-mediated protein phosphorylation in exponentially growing D39 pneumococcal cells.
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Affiliation(s)
| | - Merrin Joseph
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - Jiaqi J. Zheng
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - Amilcar J. Perez
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - Irfan Manzoor
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - Britta E. Rued
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - John D. Richardson
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - Pavel Branny
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Linda Doubravová
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Orietta Massidda
- Department of Cellular, Computational, and Integrative Biology, University of Trento, Italy
| | - Malcolm E. Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
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7
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Tsui HCT, Joseph M, Zheng JJ, Perez AJ, Manzoor I, Rued BE, Richardson JD, Branny P, Doubravová L, Massidda O, Winkler ME. Chromosomal Duplications of MurZ (MurA2) or MurA (MurA1), Amino Acid Substitutions in MurZ (MurA2), and Absence of KhpAB Obviate the Requirement for Protein Phosphorylation in Streptococcus pneumoniae D39. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.26.534294. [PMID: 37034771 PMCID: PMC10081211 DOI: 10.1101/2023.03.26.534294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Abstract
GpsB links peptidoglycan synthases to other proteins that determine the shape of the respiratory pathogen Streptococcus pneumoniae (pneumococcus; Spn ) and other low-GC Gram-positive bacteria. GpsB is also required for phosphorylation of proteins by the essential StkP( Spn ) Ser/Thr protein kinase. Here we report three classes of frequently arising chromosomal duplications (≈21-176 genes) containing murZ (MurZ-family homolog of MurA) or murA that suppress Δ gpsB or Δ stkP . These duplications arose from three different repeated sequences and demonstrate the facility of pneumococcus to modulate gene dosage of numerous genes. Overproduction of MurZ or MurA alone or overexpression of MurZ caused by Δ khpAB mutations suppressed Δ gpsB or Δ stkP phenotypes to varying extents. Δ gpsB and Δ stkP were also suppressed by MurZ amino-acid changes distant from the active site, including one in commonly studied laboratory strains, and by truncation or deletion of the homolog of IreB(ReoM). Unlike in other Gram-positive bacteria, MurZ is predominant to MurA in pneumococcal cells. However, Δ gpsB and Δ stkP were not suppressed by Δ clpCP , which did not alter MurZ or MurA amounts. These results support a model in which regulation of MurZ and MurA activity, likely by IreB( Spn ), is the only essential requirement for protein phosphorylation in exponentially growing D39 pneumococcal cells.
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8
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Fritsch VN, Linzner N, Busche T, Said N, Weise C, Kalinowski J, Wahl MC, Antelmann H. The MerR-family regulator NmlR is involved in the defense against oxidative stress in Streptococcus pneumoniae. Mol Microbiol 2023; 119:191-207. [PMID: 36349475 DOI: 10.1111/mmi.14999] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 10/25/2022] [Accepted: 10/30/2022] [Indexed: 11/11/2022]
Abstract
Streptococcus pneumoniae has to cope with the strong oxidant hypochlorous acid (HOCl), during host-pathogen interactions. Thus, we analyzed the global gene expression profile of S. pneumoniae D39 towards HOCl stress. In the RNA-seq transcriptome, the NmlR, SifR, CtsR, HrcA, SczA and CopY regulons and the etrx1-ccdA1-msrAB2 operon were most strongly induced under HOCl stress, which participate in the oxidative, electrophile and metal stress response in S. pneumoniae. The MerR-family regulator NmlR harbors a conserved Cys52 and controls the alcohol dehydrogenase-encoding adhC gene under carbonyl and NO stress. We demonstrated that NmlR senses also HOCl stress to activate transcription of the nmlR-adhC operon. HOCl-induced transcription of adhC required Cys52 of NmlR in vivo. Using mass spectrometry, NmlR was shown to be oxidized to intersubunit disulfides or S-glutathionylated under oxidative stress in vitro. A broccoli-FLAP-based assay further showed that both NmlR disulfides significantly increased transcription initiation at the nmlR promoter by RNAP in vitro, which depends on Cys52. Phenotype analyses revealed that NmlR functions in the defense against oxidative stress and promotes survival of S. pneumoniae during macrophage infections. In conclusion, NmlR was characterized as HOCl-sensing transcriptional regulator, which activates transcription of adhC under oxidative stress by thiol switches in S. pneumoniae.
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Affiliation(s)
| | - Nico Linzner
- Institute of Biology-Microbiology, Freie Universität Berlin, Berlin, Germany
| | - Tobias Busche
- Center for Biotechnology, University Bielefeld, Bielefeld, Germany.,NGS Core Facility, Medical School OWL, Bielefeld University, Bielefeld, Germany
| | - Nelly Said
- Laboratory of Structural Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Christoph Weise
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Jörn Kalinowski
- Center for Biotechnology, University Bielefeld, Bielefeld, Germany
| | - Markus C Wahl
- Laboratory of Structural Biochemistry, Freie Universität Berlin, Berlin, Germany.,Macromolecular Crystallography, Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | - Haike Antelmann
- Institute of Biology-Microbiology, Freie Universität Berlin, Berlin, Germany
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9
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Pan Y, Zou J, Zhang K, Wang X, Ma Q, Mei L, Li Y, Pan Y. ZccE, a P-type ATPase contributing to biofilm formation and competitiveness in Streptococcus mutans. Mol Oral Microbiol 2023; 38:198-211. [PMID: 36622758 DOI: 10.1111/omi.12405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 11/26/2022] [Accepted: 12/28/2022] [Indexed: 01/10/2023]
Abstract
Most living organisms require zinc for survival; however, excessive amounts of this trace element can be toxic. Therefore, the frequent fluctuations of salivary zinc, caused by the low physiological level and the frequent introduction of exogenous zinc ions, present a serious challenge for bacteria colonizing the oral cavity. Streptococcus mutans is considered one of the main bacterial pathobiont in dental caries. Here, we verified the role of a P-type ATPase ZccE as the main zinc-exporting transporter in S. mutans and delineated the effects of zinc toxification caused by zccE deletion in the physiology of this bacterium. The deletion of the gene zccE severely impaired the ability of S. mutans to grow under high zinc stress conditions. Intracellular metal quantification using inductively coupled plasma optical emission spectrometer revealed that the zccE mutant exhibited approximately two times higher zinc accumulation than the wild type when grown in the presence of a subinhibitory zinc concentration. Biofilm formation analysis revealed less single-strain biofilm formation and competitive weakness in the dual-species biofilm formed with Streptococcus sanguinis for zccE mutant under high zinc stress. The quantitive reverse transcription polymerase chain reaction test revealed decreased expressions of gtfB, gtfC, and nlmC in the mutant strain under excessive zinc treatment. Collectively, these findings suggest that ZccE plays an important role in the zinc detoxification of S. mutans and that zinc is a growth-limiting factor for S. mutans within the dental biofilm.
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Affiliation(s)
- Yangyang Pan
- Department of Pediatric Dentistry, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Jing Zou
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Keke Zhang
- Institute of Stomatology, School & Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Xiping Wang
- Department of Pediatric Dentistry, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Qizhao Ma
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Liqin Mei
- Department of Pediatric Dentistry, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Yuqing Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yihuai Pan
- Department of Endodontics, School & Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
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10
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Murdoch CC, Skaar EP. Nutritional immunity: the battle for nutrient metals at the host-pathogen interface. Nat Rev Microbiol 2022; 20:657-670. [PMID: 35641670 PMCID: PMC9153222 DOI: 10.1038/s41579-022-00745-6] [Citation(s) in RCA: 123] [Impact Index Per Article: 61.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2022] [Indexed: 12/21/2022]
Abstract
Trace metals are essential micronutrients required for survival across all kingdoms of life. From bacteria to animals, metals have critical roles as both structural and catalytic cofactors for an estimated third of the proteome, representing a major contributor to the maintenance of cellular homeostasis. The reactivity of metal ions engenders them with the ability to promote enzyme catalysis and stabilize reaction intermediates. However, these properties render metals toxic at high concentrations and, therefore, metal levels must be tightly regulated. Having evolved in close association with bacteria, vertebrate hosts have developed numerous strategies of metal limitation and intoxication that prevent bacterial proliferation, a process termed nutritional immunity. In turn, bacterial pathogens have evolved adaptive mechanisms to survive in conditions of metal depletion or excess. In this Review, we discuss mechanisms by which nutrient metals shape the interactions between bacterial pathogens and animal hosts. We explore the cell-specific and tissue-specific roles of distinct trace metals in shaping bacterial infections, as well as implications for future research and new therapeutic development.
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Affiliation(s)
- Caitlin C Murdoch
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
- Vanderbilt Institute for Infection, Immunology and Inflammation, 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.
- Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University School of Medicine, Nashville, TN, USA.
- Vanderbilt Institute for Chemical Biology, Vanderbilt University, Nashville, TN, USA.
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11
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ZccE is a Novel P-type ATPase That Protects Streptococcus mutans Against Zinc Intoxication. PLoS Pathog 2022; 18:e1010477. [PMID: 35939512 PMCID: PMC9387928 DOI: 10.1371/journal.ppat.1010477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 08/18/2022] [Accepted: 07/19/2022] [Indexed: 11/19/2022] Open
Abstract
Zinc is a trace metal that is essential to all forms of life, but that becomes toxic at high concentrations. Because it has both antimicrobial and anti-inflammatory properties and low toxicity to mammalian cells, zinc has been used as a therapeutic agent for centuries to treat a variety of infectious and non-infectious conditions. While the usefulness of zinc-based therapies in caries prevention is controversial, zinc is incorporated into toothpaste and mouthwash formulations to prevent gingivitis and halitosis. Despite this widespread use of zinc in oral healthcare, the mechanisms that allow Streptococcus mutans, a keystone pathogen in dental caries and prevalent etiological agent of infective endocarditis, to overcome zinc toxicity are largely unknown. Here, we discovered that S. mutans is inherently more tolerant to high zinc stress than all other species of streptococci tested, including commensal streptococci associated with oral health. Using a transcriptome approach, we uncovered several potential strategies utilized by S. mutans to overcome zinc toxicity. Among them, we identified a previously uncharacterized P-type ATPase transporter and cognate transcriptional regulator, which we named ZccE and ZccR respectively, as responsible for the remarkable high zinc tolerance of S. mutans. In addition to zinc, we found that ZccE, which was found to be unique to S. mutans strains, mediates tolerance to at least three additional metal ions, namely cadmium, cobalt, and copper. Loss of the ability to maintain zinc homeostasis when exposed to high zinc stress severely disturbed zinc:manganese ratios, leading to heightened peroxide sensitivity that was alleviated by manganese supplementation. Finally, we showed that the ability of the ΔzccE strain to stably colonize the rat tooth surface after topical zinc treatment was significantly impaired, providing proof of concept that ZccE and ZccR are suitable targets for the development of antimicrobial therapies specifically tailored to kill S. mutans. Dental caries is an overlooked infectious disease affecting more than 50% of the adult population. While several bacteria that reside in dental plaque have been associated with caries development and progression, Streptococcus mutans is deemed a keystone caries pathogen due to its capacity to modify the dental plaque environment in a way that is conducive with disease development. Zinc is an essential trace metal to life but toxic when encountered at high concentrations, to the point that it has been used as an antimicrobial for centuries. Despite the widespread use of zinc in oral healthcare products, little is known about the mechanisms utilized by oral bacteria to overcome its toxic effects. In this study, we discovered that S. mutans can tolerate exposure to much higher levels of zinc than closely related streptococcal species, including species that antagonize S. mutans and are associated with oral health. In this study, we identified a new metal transporter, named ZccE, as directly responsible for the inherently high zinc tolerance of S. mutans. Because ZccE is not present in other bacteria, our findings provide a new target for the development of a zinc-based therapy specifically tailored to kill S. mutans.
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12
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Martin JE, Waters LS. Regulation of Bacterial Manganese Homeostasis and Usage During Stress Responses and Pathogenesis. Front Mol Biosci 2022; 9:945724. [PMID: 35911964 PMCID: PMC9334652 DOI: 10.3389/fmolb.2022.945724] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 06/21/2022] [Indexed: 11/13/2022] Open
Abstract
Manganese (Mn) plays a multifaceted role in the survival of pathogenic and symbiotic bacteria in eukaryotic hosts, and it is also important for free-living bacteria to grow in stressful environments. Previous research has uncovered components of the bacterial Mn homeostasis systems that control intracellular Mn levels, many of which are important for virulence. Multiple studies have also identified proteins that use Mn once it is inside the cell, including Mn-specific enzymes and enzymes transiently loaded with Mn for protection during oxidative stress. Emerging evidence continues to reveal proteins involved in maintaining Mn homeostasis, as well as enzymes that can bind Mn. For some of these enzymes, Mn serves as an essential cofactor. For other enzymes, mismetallation with Mn can lead to inactivation or poor activity. Some enzymes may even potentially be regulated by differential metallation with Mn or zinc (Zn). This review focuses on new developments in regulatory mechanisms that affect Mn homeostasis and usage, additional players in Mn import that increase bacterial survival during pathogenesis, and the interplay between Mn and other metals during Mn-responsive physiological processes. Lastly, we highlight lessons learned from fundamental research that are now being applied to bacterial interactions within larger microbial communities or eukaryotic hosts.
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Affiliation(s)
- Julia E. Martin
- Department of Biological Sciences, Idaho State University, Pocatello, ID, United States
| | - Lauren S. Waters
- Department of Chemistry, University of Wisconsin Oshkosh, Oshkosh, WI, United States
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13
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Bacterial Transcriptional Regulators: A Road Map for Functional, Structural, and Biophysical Characterization. Int J Mol Sci 2022; 23:ijms23042179. [PMID: 35216300 PMCID: PMC8879271 DOI: 10.3390/ijms23042179] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 02/11/2022] [Accepted: 02/11/2022] [Indexed: 12/12/2022] Open
Abstract
The different niches through which bacteria move during their life cycle require a fast response to the many environmental queues they encounter. The sensing of these stimuli and their correct response is driven primarily by transcriptional regulators. This kind of protein is involved in sensing a wide array of chemical species, a process that ultimately leads to the regulation of gene transcription. The allosteric-coupling mechanism of sensing and regulation is a central aspect of biological systems and has become an important field of research during the last decades. In this review, we summarize the state-of-the-art techniques applied to unravel these complex mechanisms. We introduce a roadmap that may serve for experimental design, depending on the answers we seek and the initial information we have about the system of study. We also provide information on databases containing available structural information on each family of transcriptional regulators. Finally, we discuss the recent results of research about the allosteric mechanisms of sensing and regulation involving many transcriptional regulators of interest, highlighting multipronged strategies and novel experimental techniques. The aim of the experiments discussed here was to provide a better understanding at a molecular level of how bacteria adapt to the different environmental threats they face.
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14
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Cellular Mn/Zn Ratio Influences Phosphoglucomutase Activity and Capsule Production in Streptococcus pneumoniae D39. J Bacteriol 2021; 203:e0060220. [PMID: 33875543 PMCID: PMC8316032 DOI: 10.1128/jb.00602-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Capsular polysaccharide (CPS) is a major virulence determinant for many human-pathogenic bacteria. Although the essential functional roles for CPS in bacterial virulence have been established, knowledge of how CPS production is regulated remains limited. Streptococcus pneumoniae (pneumococcus) CPS expression levels and overall thickness change in response to available oxygen and carbohydrate. These nutrients in addition to transition metal ions can vary significantly between host environmental niches and infection stage. Since the pneumococcus must modulate CPS expression among various host niches during disease progression, we examined the impact of the nutritional transition metal availability of manganese (Mn) and zinc (Zn) on CPS production. We demonstrate that increased Mn/Zn ratios increase CPS production via Mn-dependent activation of the phosphoglucomutase Pgm, an enzyme that functions at the branch point between glycolysis and the CPS biosynthetic pathway in a transcription-independent manner. Furthermore, we find that the downstream CPS protein CpsB, an Mn-dependent phosphatase, does not promote aberrant dephosphorylation of its target capsule-tyrosine kinase CpsD during Mn stress. Together, these data reveal a direct role for cellular Mn/Zn ratios in the regulation of CPS biosynthesis via the direct activation of Pgm. We propose a multilayer mechanism used by the pneumococcus in regulating CPS levels across various host niches. IMPORTANCE Evolving evidence strongly indicates that maintenance of metal homeostasis is essential for establishing colonization and continued growth of bacterial pathogens in the vertebrate host. In this study, we demonstrate the impact of cellular manganese/zinc (Mn/Zn) ratios on bacterial capsular polysaccharide (CPS) production, an important virulence determinant of many human-pathogenic bacteria, including Streptococcus pneumoniae. We show that higher Mn/Zn ratios increase CPS production via the Mn-dependent activation of the phosphoglucomutase Pgm, an enzyme that functions at the branch point between glycolysis and the CPS biosynthetic pathway. The findings provide a direct role for Mn/Zn homeostasis in the regulation of CPS expression levels and further support the ability of metal cations to act as important cellular signaling mediators in bacteria.
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15
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Cellular Management of Zinc in Group B Streptococcus Supports Bacterial Resistance against Metal Intoxication and Promotes Disseminated Infection. mSphere 2021; 6:6/3/e00105-21. [PMID: 34011683 PMCID: PMC8265624 DOI: 10.1128/msphere.00105-21] [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] [Indexed: 11/20/2022] Open
Abstract
Zinc is an essential trace element for normal bacterial physiology but, divergently, can intoxicate bacteria at high concentrations. Here, we define the molecular systems for Zn detoxification in Streptococcus agalactiae, also known as group B streptococcus, and examine the effects of resistance to Zn stress on virulence. We compared the growth of wild-type bacteria and mutants deleted for the Zn exporter, czcD, and the response regulator, sczA, using Zn-stress conditions in vitro Macrophage antibiotic protection assays and a mouse model of disseminated infection were used to assess virulence. Global bacterial transcriptional responses to Zn stress were defined by RNA sequencing and quantitative reverse transcription-PCR. czcD and sczA enabled S. agalactiae to survive Zn stress, with the putative CzcD efflux system activated by SczA. Additional genes activated in response to Zn stress encompassed divalent cation transporters that contribute to regulation of Mn and Fe homeostasis. In vivo, the czcD-sczA Zn management axis supported virulence in the blood, heart, liver, and bladder. Additionally, several genes not previously linked to Zn stress in any bacterium, including, most notably, arcA for arginine deamination, also mediated resistance to Zn stress, representing a novel molecular mechanism of bacterial resistance to metal intoxication. Taken together, these findings show that S. agalactiae responds to Zn stress by sczA regulation of czcD, with additional novel mechanisms of resistance supported by arcA, encoding arginine deaminase. Cellular management of Zn stress in S. agalactiae supports virulence by facilitating bacterial survival in the host during systemic infection.IMPORTANCE Streptococcus agalactiae, also known as group B streptococcus, is an opportunistic pathogen that causes various diseases in humans and animals. This bacterium has genetic systems that enable zinc detoxification in environments of metal stress, but these systems remain largely undefined. Using a combination of genomic, genetic, and cellular assays, we show that this pathogen controls Zn export through CzcD to manage Zn stress and utilizes a system of arginine deamination never previously linked to metal stress responses in bacteria to survive metal intoxication. We show that these systems are crucial for survival of S. agalactiae in vitro during Zn stress and also enhance virulence during systemic infection in mice. These discoveries establish new molecular mechanisms of resistance to metal intoxication in bacteria; we suggest these mechanisms operate in other bacteria as a way to sustain microbial survival under conditions of metal stress, including in host environments.
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16
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Principles and practice of determining metal-protein affinities. Biochem J 2021; 478:1085-1116. [PMID: 33710331 PMCID: PMC7959690 DOI: 10.1042/bcj20200838] [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: 12/11/2020] [Revised: 02/05/2021] [Accepted: 02/11/2021] [Indexed: 01/02/2023]
Abstract
Metal ions play many critical roles in biology, as structural and catalytic cofactors, and as cell regulatory and signalling elements. The metal–protein affinity, expressed conveniently by the metal dissociation constant, KD, describes the thermodynamic strength of a metal–protein interaction and is a key parameter that can be used, for example, to understand how proteins may acquire metals in a cell and to identify dynamic elements (e.g. cofactor binding, changing metal availabilities) which regulate protein metalation in vivo. Here, we outline the fundamental principles and practical considerations that are key to the reliable quantification of metal–protein affinities. We review a selection of spectroscopic probes which can be used to determine protein affinities for essential biological transition metals (including Mn(II), Fe(II), Co(II), Ni(II), Cu(I), Cu(II) and Zn(II)) and, using selected examples, demonstrate how rational probe selection combined with prudent experimental design can be applied to determine accurate KD values.
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17
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Cuajungco MP, Ramirez MS, Tolmasky ME. Zinc: Multidimensional Effects on Living Organisms. Biomedicines 2021; 9:biomedicines9020208. [PMID: 33671781 PMCID: PMC7926802 DOI: 10.3390/biomedicines9020208] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 02/03/2021] [Accepted: 02/09/2021] [Indexed: 12/28/2022] Open
Abstract
Zinc is a redox-inert trace element that is second only to iron in abundance in biological systems. In cells, zinc is typically buffered and bound to metalloproteins, but it may also exist in a labile or chelatable (free ion) form. Zinc plays a critical role in prokaryotes and eukaryotes, ranging from structural to catalytic to replication to demise. This review discusses the influential properties of zinc on various mechanisms of bacterial proliferation and synergistic action as an antimicrobial element. We also touch upon the significance of zinc among eukaryotic cells and how it may modulate their survival and death through its inhibitory or modulatory effect on certain receptors, enzymes, and signaling proteins. A brief discussion on zinc chelators is also presented, and chelating agents may be used with or against zinc to affect therapeutics against human diseases. Overall, the multidimensional effects of zinc in cells attest to the growing number of scientific research that reveal the consequential prominence of this remarkable transition metal in human health and disease.
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18
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Identification of Zinc-Dependent Mechanisms Used by Group B Streptococcus To Overcome Calprotectin-Mediated Stress. mBio 2020; 11:mBio.02302-20. [PMID: 33173000 PMCID: PMC7667036 DOI: 10.1128/mbio.02302-20] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Group B Streptococcus (GBS) asymptomatically colonizes the female reproductive tract but is a common causative agent of meningitis. GBS meningitis is characterized by extensive infiltration of neutrophils carrying high concentrations of calprotectin, a metal chelator. To persist within inflammatory sites and cause invasive disease, GBS must circumvent host starvation attempts. Here, we identified global requirements for GBS survival during calprotectin challenge, including known and putative systems involved in metal ion transport. We characterized the role of zinc import in tolerating calprotectin stress in vitro and in a mouse model of infection. We observed that a global zinc uptake mutant was less virulent than the parental GBS strain and found calprotectin knockout mice to be equally susceptible to infection by wild-type (WT) and mutant strains. These findings suggest that calprotectin production at the site of infection results in a zinc-limited environment and reveals the importance of GBS metal homeostasis to invasive disease. Nutritional immunity is an elegant host mechanism used to starve invading pathogens of necessary nutrient metals. Calprotectin, a metal-binding protein, is produced abundantly by neutrophils and is found in high concentrations within inflammatory sites during infection. Group B Streptococcus (GBS) colonizes the gastrointestinal and female reproductive tracts and is commonly associated with severe invasive infections in newborns such as pneumonia, sepsis, and meningitis. Although GBS infections induce robust neutrophil recruitment and inflammation, the dynamics of GBS and calprotectin interactions remain unknown. Here, we demonstrate that disease and colonizing isolate strains exhibit susceptibility to metal starvation by calprotectin. We constructed a mariner transposon (Krmit) mutant library in GBS and identified 258 genes that contribute to surviving calprotectin stress. Nearly 20% of all underrepresented mutants following treatment with calprotectin are predicted metal transporters, including known zinc systems. As calprotectin binds zinc with picomolar affinity, we investigated the contribution of GBS zinc uptake to overcoming calprotectin-imposed starvation. Quantitative reverse transcriptase PCR (qRT-PCR) revealed a significant upregulation of genes encoding zinc-binding proteins, adcA, adcAII, and lmb, following calprotectin exposure, while growth in calprotectin revealed a significant defect for a global zinc acquisition mutant (ΔadcAΔadcAIIΔlmb) compared to growth of the GBS wild-type (WT) strain. Furthermore, mice challenged with the ΔadcAΔadcAIIΔlmb mutant exhibited decreased mortality and significantly reduced bacterial burden in the brain compared to mice infected with WT GBS; this difference was abrogated in calprotectin knockout mice. Collectively, these data suggest that GBS zinc transport machinery is important for combatting zinc chelation by calprotectin and establishing invasive disease.
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19
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von Pein JB, Stocks CJ, Schembri MA, Kapetanovic R, Sweet MJ. An alloy of zinc and innate immunity: Galvanising host defence against infection. Cell Microbiol 2020; 23:e13268. [PMID: 32975847 DOI: 10.1111/cmi.13268] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/31/2020] [Accepted: 09/03/2020] [Indexed: 12/16/2022]
Abstract
Innate immune cells such as macrophages and neutrophils initiate protective inflammatory responses and engage antimicrobial responses to provide frontline defence against invading pathogens. These cells can both restrict the availability of certain transition metals that are essential for microbial growth and direct toxic concentrations of metals towards pathogens as antimicrobial responses. Zinc is important for the structure and function of many proteins, however excess zinc can be cytotoxic. In recent years, several studies have revealed that innate immune cells can deliver toxic concentrations of zinc to intracellular pathogens. In this review, we discuss the importance of zinc status during infectious disease and the evidence for zinc intoxication as an innate immune antimicrobial response. Evidence for pathogen subversion of this response is also examined. The likely mechanisms, including the involvement of specific zinc transporters that facilitate delivery of zinc by innate immune cells for metal ion poisoning of pathogens are also considered. Precise mechanisms by which excess levels of zinc can be toxic to microorganisms are then discussed, particularly in the context of synergy with other antimicrobial responses. Finally, we highlight key unanswered questions in this emerging field, which may offer new opportunities for exploiting innate immune responses for anti-infective development.
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Affiliation(s)
- Jessica B von Pein
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
| | - Claudia J Stocks
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
| | - Mark A Schembri
- Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Ronan Kapetanovic
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
| | - Matthew J Sweet
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
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20
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Ray A, Edmonds KA, Palmer LD, Skaar EP, Giedroc DP. Staphylococcus aureus Glucose-Induced Biofilm Accessory Protein A (GbaA) Is a Monothiol-Dependent Electrophile Sensor. Biochemistry 2020; 59:2882-2895. [PMID: 32697076 DOI: 10.1021/acs.biochem.0c00347] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Staphylococcus aureus is a commensal pathogen that has evolved to protect itself from unfavorable conditions by forming complex community structures termed biofilms. The regulation of the formation of these structures is multifactorial and in S. aureus involves a number of transcriptional regulators. GbaA (glucose-induced biofilm accessory protein A) is a tetracycline repressor (TetR) family regulator that harbors two conserved Cys residues (C55 and C104) and impacts the regulation of formation of poly-N-acetylglucosamine-based biofilms in many methicillin-resistant S. aureus (MRSA) strains. Here, we show that GbaA-regulated transcription of a divergently transcribed operon in a MRSA strain can be induced by potent electrophiles, N-ethylmaleimide and methylglyoxal. Strikingly, induction of transcription in cells requires C55 or C104, but not both. These findings are consistent with in vitro small-angle X-ray scattering, chemical modification, and DNA operator binding experiments, which reveal that both reduced and intraprotomer (C55-C104) disulfide forms of GbaA have very similar overall structures and each exhibits a high affinity for the DNA operator, while DNA binding is strongly inhibited by derivatization of one or the other Cys residues via formation of a mixed disulfide with bacillithiol disulfide or a monothiol derivatization adduct with NEM. While both Cys residues are reactive toward electrophiles, C104 in the regulatory domain is the more reactive thiolate. These characteristics enhance the inducer specificity of GbaA and would preclude sensing of generalized cellular oxidative stress via disulfide bond formation. The implications of the findings for GbaA function in MRSA strains are discussed.
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Affiliation(s)
- Abhinaba Ray
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102, United States
| | - Katherine A Edmonds
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102, United States
| | - Lauren D Palmer
- Department of Pathology, Microbiology, and Immunology and Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Eric P Skaar
- Department of Pathology, Microbiology, and Immunology and Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - David P Giedroc
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102, United States.,Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405-7102, United States
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21
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Jordan MR, Wang J, Capdevila DA, Giedroc DP. Multi-metal nutrient restriction and crosstalk in metallostasis systems in microbial pathogens. Curr Opin Microbiol 2020; 55:17-25. [PMID: 32062305 DOI: 10.1016/j.mib.2020.01.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 01/03/2020] [Accepted: 01/09/2020] [Indexed: 12/26/2022]
Abstract
Transition metals from manganese to zinc function as catalytic and structural cofactors for an amazing diversity of proteins and enzymes, and thus are essential for all forms of life. During infection, inflammatory host proteins limit the accessibility of multiple transition metals to invading pathogens in a process termed nutritional immunity. In order to respond to host-mediated metal starvation, bacteria employ both protein and RNA-based mechanisms to sense prevailing transition metal concentrations that collectively regulate systems-level strategies to maintain cellular metallostasis. In this review, we discuss a number of recent advances in our understanding of how bacteria orchestrate the adaptive response to host-mediated multi-metal restriction, highlighting crosstalk among these regulatory systems.
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Affiliation(s)
- Matthew R Jordan
- Departments of Chemistry and of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, United States
| | - Jiefei Wang
- Departments of Chemistry and of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, United States
| | - Daiana A Capdevila
- Fundación Instituto Leloir, Av. Patricias Argentinas 435, Buenos Aires C1405BWE, Argentina
| | - David P Giedroc
- Departments of Chemistry and of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, United States.
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22
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Eijkelkamp BA, Morey JR, Neville SL, Tan A, Pederick VG, Cole N, Singh PP, Ong CLY, Gonzalez de Vega R, Clases D, Cunningham BA, Hughes CE, Comerford I, Brazel EB, Whittall JJ, Plumptre CD, McColl SR, Paton JC, McEwan AG, Doble PA, McDevitt CA. Dietary zinc and the control of Streptococcus pneumoniae infection. PLoS Pathog 2019; 15:e1007957. [PMID: 31437249 PMCID: PMC6705770 DOI: 10.1371/journal.ppat.1007957] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 07/03/2019] [Indexed: 12/21/2022] Open
Abstract
Human zinc deficiency increases susceptibility to bacterial infection. Although zinc supplementation therapies can reduce the impact of disease, the molecular basis for protection remains unclear. Streptococcus pneumoniae is a major cause of bacterial pneumonia, which is prevalent in regions of zinc deficiency. We report that dietary zinc levels dictate the outcome of S. pneumoniae infection in a murine model. Dietary zinc restriction impacts murine tissue zinc levels with distribution post-infection altered, and S. pneumoniae virulence and infection enhanced. Although the activation and infiltration of murine phagocytic cells was not affected by zinc restriction, their efficacy of bacterial control was compromised. S. pneumoniae was shown to be highly sensitive to zinc intoxication, with this process impaired in zinc restricted mice and isolated phagocytic cells. Collectively, these data show how dietary zinc deficiency increases sensitivity to S. pneumoniae infection while revealing a role for zinc as a component of host antimicrobial defences. Zinc deficiency affects one-third of the world’s population and is associated with an increased susceptibility to bacterial infection. Despite this, the molecular basis for how zinc deficiency compromises host control of infection remains to be understood. We show that dietary zinc deficiency impacts host tissue zinc abundances and its mobilization during infection by the major respiratory pathogen Streptococcus pneumoniae. Zinc acts as a direct antimicrobial against the pathogen, mobilized by phagocytic cells as a component of the innate immune response. Although immune activation and infiltration of phagocytic cells is unaffected by host zinc status, the lack of antimicrobial zinc compromises bacterial control in zinc deficient hosts. These findings highlight the importance of zinc sufficiency in resisting bacterial infection.
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Affiliation(s)
- Bart A Eijkelkamp
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - Jacqueline R Morey
- Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - Stephanie L Neville
- Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, Australia.,Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Aimee Tan
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Victoria G Pederick
- Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - Nerida Cole
- The Atomic Medicine Initiative, University of Technology, Broadway, Sydney, New South Wales, Australia.,ARC Training Centre in Biodevices, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Victoria, Australia
| | - Prashina P Singh
- The Atomic Medicine Initiative, University of Technology, Broadway, Sydney, New South Wales, Australia
| | - Cheryl-Lynn Y Ong
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
| | - Raquel Gonzalez de Vega
- The Atomic Medicine Initiative, University of Technology, Broadway, Sydney, New South Wales, Australia
| | - David Clases
- The Atomic Medicine Initiative, University of Technology, Broadway, Sydney, New South Wales, Australia
| | - Bliss A Cunningham
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Catherine E Hughes
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - Iain Comerford
- Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - Erin B Brazel
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - Jonathan J Whittall
- Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - Charles D Plumptre
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - Shaun R McColl
- Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - James C Paton
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - Alastair G McEwan
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
| | - Philip A Doble
- The Atomic Medicine Initiative, University of Technology, Broadway, Sydney, New South Wales, Australia
| | - Christopher A McDevitt
- Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, Australia.,Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
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23
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Murarka P, Bagga T, Singh P, Rangra S, Srivastava P. Isolation and identification of a TetR family protein that regulates the biodesulfurization operon. AMB Express 2019; 9:71. [PMID: 31127394 PMCID: PMC6534649 DOI: 10.1186/s13568-019-0801-x] [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: 04/30/2019] [Accepted: 05/16/2019] [Indexed: 11/10/2022] Open
Abstract
Biodesulfurization helps in removal of sulfur from organosulfur present in petroleum fractions. All microorganisms isolated to date harbor a desulfurization operon consisting of three genes dszA, -B and -C which encode for monooxygenases (DszA & C) and desulfinase (DszB). Most of the studies have been carried out using dibenzothiophene as the model organosulfur compound, which is converted into 2 hydroxybiphenyl by a 4S pathway which maintains the calorific value of fuel. There are few studies reported on the regulation of this operon. However, there are no reports on the proteins which can enhance the activity of the operon. In the present study, we used in vitro and in vivo methods to identify a novel TetR family transcriptional regulator from Gordonia sp. IITR100 which functions as an activator of the dsz operon. Activation by TetR family regulator resulted in enhanced levels of desulfurization enzymes in Gordonia sp. IITR100. Activation was observed only when the 385 bp full length promoter was used. Upstream sequences between - 385 and - 315 were found to be responsible for activation. We provide evidence that the TetR family transcription regulator serves as an activator in other biodesulfurizing microorganisms such as Rhodococcus erythropolis IGTS8 and heterologous host Escherichia coli. This is the first report on the isolation of a possible transcriptional regulator that activates the desulfurization operon resulting in improved biodesulfurization.
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Sheldon JR, Skaar EP. Metals as phagocyte antimicrobial effectors. Curr Opin Immunol 2019; 60:1-9. [PMID: 31063946 DOI: 10.1016/j.coi.2019.04.002] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 04/03/2019] [Accepted: 04/03/2019] [Indexed: 12/30/2022]
Abstract
Transition metal ions are essential to bacterial pathogens and their hosts alike but are harmful in excess. In an effort to curtail the replication of intracellular bacteria, host phagocytes exploit both the essentiality and toxicity of transition metals. In the paradigmatic description of nutritional immunity, iron and manganese are withheld from phagosomes to starve microbial invaders of these nutrients. Conversely, the destructive properties of copper and zinc appear to be harnessed by phagocytes, where these metals are delivered in excess to phagosomes to intoxicate internalized bacteria. Here, we briefly summarize key players in metal withholding from intracellular pathogens, before focusing on recent findings supporting the function of copper and zinc as phagocyte antimicrobial effectors. The mechanisms of copper and zinc toxicity are explored, along with strategies employed by intracellular bacterial pathogens to avoid killing by these metals.
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Affiliation(s)
- Jessica R Sheldon
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Eric P Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States; Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States.
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25
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Sikanyika M, Aragão D, McDevitt CA, Maher MJ. The structure and activity of the glutathione reductase from Streptococcus pneumoniae. Acta Crystallogr F Struct Biol Commun 2019; 75:54-61. [PMID: 30605126 PMCID: PMC6317452 DOI: 10.1107/s2053230x18016527] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 11/20/2018] [Indexed: 11/11/2022] Open
Abstract
The glutathione reductase (GR) from Streptococcus pneumoniae is a flavoenzyme that catalyzes the reduction of oxidized glutathione (GSSG) to its reduced form (GSH) in the cytoplasm of this bacterium. The maintenance of an intracellular pool of GSH is critical for the detoxification of reactive oxygen and nitrogen species and for intracellular metal tolerance to ions such as zinc. Here, S. pneumoniae GR (SpGR) was overexpressed and purified and its crystal structure determined at 2.56 Å resolution. SpGR shows overall structural similarity to other characterized GRs, with a dimeric structure that includes an antiparallel β-sheet at the dimer interface. This observation, in conjunction with comparisons with the interface structures of other GR enzymes, allows the classification of these enzymes into three classes. Analyses of the kinetic properties of SpGR revealed a significantly higher value for Km(GSSG) (231.2 ± 24.7 µM) in comparison to other characterized GR enzymes.
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Affiliation(s)
- Mwilye Sikanyika
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Australia
| | - David Aragão
- Australian Synchrotron, Australian Nuclear Science and Technology Organisation, 800 Blackburn Road, Clayton, Victoria 3168, Australia
| | - Christopher A. McDevitt
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria 3000, Australia
| | - Megan J. Maher
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Australia
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Cao K, Lai F, Zhao XL, Wei QX, Miao XY, Ge R, He QY, Sun X. The mechanism of iron-compensation for manganese deficiency of Streptococcus pneumoniae. J Proteomics 2018; 184:62-70. [DOI: 10.1016/j.jprot.2018.06.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 05/17/2018] [Accepted: 06/07/2018] [Indexed: 12/18/2022]
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27
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Eijkelkamp BA, Begg SL, Pederick VG, Trapetti C, Gregory MK, Whittall JJ, Paton JC, McDevitt CA. Arachidonic Acid Stress Impacts Pneumococcal Fatty Acid Homeostasis. Front Microbiol 2018; 9:813. [PMID: 29867785 PMCID: PMC5958418 DOI: 10.3389/fmicb.2018.00813] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 04/10/2018] [Indexed: 12/21/2022] Open
Abstract
Free fatty acids hold dual roles during infection, serving to modulate the host immune response while also functioning directly as antimicrobials. Of particular importance are the long chain polyunsaturated fatty acids, which are not commonly found in bacterial organisms, that have been proposed to have antibacterial roles. Arachidonic acid (AA) is a highly abundant long chain polyunsaturated fatty acid and we examined its effect upon Streptococcus pneumoniae. Here, we observed that in a murine model of S. pneumoniae infection the concentration of AA significantly increases in the blood. The impact of AA stress upon the pathogen was then assessed by a combination of biochemical, biophysical and microbiological assays. In vitro bacterial growth and intra-macrophage survival assays revealed that AA has detrimental effects on pneumococcal fitness. Subsequent analyses demonstrated that AA exerts antimicrobial activity via insertion into the pneumococcal membrane, although this did not increase the susceptibility of the bacterium to antibiotic, oxidative or metal ion stress. Transcriptomic profiling showed that AA treatment also resulted in a dramatic down-regulation of the genes involved in fatty acid biosynthesis, in addition to impacts on other metabolic processes, such as carbon-source utilization. Hence, these data reveal that AA has two distinct mechanisms of perturbing the pneumococcal membrane composition. Collectively, this work provides a molecular basis for the antimicrobial contribution of AA to combat pneumococcal infections.
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Affiliation(s)
- Bart A Eijkelkamp
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Stephanie L Begg
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Victoria G Pederick
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Claudia Trapetti
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Melissa K Gregory
- Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
| | - Jonathan J Whittall
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - James C Paton
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Christopher A McDevitt
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
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Glauninger H, Zhang Y, Higgins KA, Jacobs AD, Martin JE, Fu Y, Coyne Rd HJ, Bruce KE, Maroney MJ, Clemmer DE, Capdevila DA, Giedroc DP. Metal-dependent allosteric activation and inhibition on the same molecular scaffold: the copper sensor CopY from Streptococcus pneumoniae. Chem Sci 2018; 9:105-118. [PMID: 29399317 PMCID: PMC5772342 DOI: 10.1039/c7sc04396a] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 11/08/2017] [Indexed: 11/21/2022] Open
Abstract
Resistance to copper (Cu) toxicity in the respiratory pathogen Streptococcus pneumoniae is regulated by the Cu-specific metallosensor CopY. CopY is structurally related to the antibiotic-resistance regulatory proteins MecI and BlaI from Staphylococcus aureus, but is otherwise poorly characterized. Here we employ a multi-pronged experimental strategy to define the Spn CopY coordination chemistry and the unique mechanism of allosteric activation by Zn(ii) and allosteric inhibition by Cu(i) of cop promoter DNA binding. We show that Zn(ii) is coordinated by a subunit-bridging 3S 1H2O complex formed by the same residues that coordinate Cu(i), as determined by X-ray absorption spectroscopy and ratiometric pulsed alkylation-mass spectrometry (rPA-MS). Apo- and Zn-bound CopY are homodimers by small angle X-ray scattering (SAXS); however, Zn stabilizes the dimer, narrows the conformational ensemble of the apo-state as revealed by ion mobility-mass spectroscopy (IM-MS), and activates DNA binding in vitro and in cells. In contrast, Cu(i) employs the same Cys pair to form a subunit-bridging, kinetically stable, multi-metallic Cu·S cluster (KCu ≈ 1016 M-1) that induces oligomerization beyond the dimer as revealed by SAXS, rPA-MS and NMR spectroscopy, leading to inhibition of DNA binding. These studies suggest that CopY employs conformational selection to drive Zn-activation of DNA binding, and a novel Cu(i)-mediated assembly mechanism that dissociates CopY from the DNA via ligand exchange-catalyzed metal substitution, leading to expression of Cu resistance genes. Mechanistic parallels to antibiotic resistance repressors MecI and BlaI are discussed.
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Affiliation(s)
- Hendrik Glauninger
- Department of Chemistry , Indiana University , Bloomington , IN 47405-7102 , USA . ; ; Tel: +1-812-856-3178 ; Tel: +1-812-856-6398
| | - Yifan Zhang
- Department of Chemistry , Indiana University , Bloomington , IN 47405-7102 , USA . ; ; Tel: +1-812-856-3178 ; Tel: +1-812-856-6398
- Department of Molecular and Cellular Biochemistry , Indiana University , Bloomington , IN 47405 , USA
| | - Khadine A Higgins
- Department of Chemistry , Indiana University , Bloomington , IN 47405-7102 , USA . ; ; Tel: +1-812-856-3178 ; Tel: +1-812-856-6398
- Department of Chemistry , Salve Regina University , Newport , RI 02840 , USA
| | - Alexander D Jacobs
- Department of Chemistry , Indiana University , Bloomington , IN 47405-7102 , USA . ; ; Tel: +1-812-856-3178 ; Tel: +1-812-856-6398
| | - Julia E Martin
- Department of Chemistry , Indiana University , Bloomington , IN 47405-7102 , USA . ; ; Tel: +1-812-856-3178 ; Tel: +1-812-856-6398
| | - Yue Fu
- Department of Chemistry , Indiana University , Bloomington , IN 47405-7102 , USA . ; ; Tel: +1-812-856-3178 ; Tel: +1-812-856-6398
- Department of Molecular and Cellular Biochemistry , Indiana University , Bloomington , IN 47405 , USA
| | - H Jerome Coyne Rd
- Department of Chemistry , Indiana University , Bloomington , IN 47405-7102 , USA . ; ; Tel: +1-812-856-3178 ; Tel: +1-812-856-6398
| | - Kevin E Bruce
- Department of Biology , Indiana University , Bloomington , IN 47405 , USA
| | - Michael J Maroney
- Department of Chemistry , University of Massachusetts , Amherst , MA 01003 , USA
| | - David E Clemmer
- Department of Chemistry , Indiana University , Bloomington , IN 47405-7102 , USA . ; ; Tel: +1-812-856-3178 ; Tel: +1-812-856-6398
| | - Daiana A Capdevila
- Department of Chemistry , Indiana University , Bloomington , IN 47405-7102 , USA . ; ; Tel: +1-812-856-3178 ; Tel: +1-812-856-6398
| | - David P Giedroc
- Department of Chemistry , Indiana University , Bloomington , IN 47405-7102 , USA . ; ; Tel: +1-812-856-3178 ; Tel: +1-812-856-6398
- Department of Molecular and Cellular Biochemistry , Indiana University , Bloomington , IN 47405 , USA
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Zheng JJ, Perez AJ, Tsui HCT, Massidda O, Winkler ME. Absence of the KhpA and KhpB (JAG/EloR) RNA-binding proteins suppresses the requirement for PBP2b by overproduction of FtsA in Streptococcus pneumoniae D39. Mol Microbiol 2017; 106:793-814. [PMID: 28941257 DOI: 10.1111/mmi.13847] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2017] [Indexed: 12/11/2022]
Abstract
Suppressor mutations were isolated that obviate the requirement for essential PBP2b in peripheral elongation of peptidoglycan from the midcells of dividing Streptococcus pneumoniae D39 background cells. One suppressor was in a gene encoding a single KH-domain protein (KhpA). ΔkhpA suppresses deletions in most, but not all (mltG), genes involved in peripheral PG synthesis and in the gpsB regulatory gene. ΔkhpA mutations reduce growth rate, decrease cell size, minimally affect shape and induce expression of the WalRK cell-wall stress regulon. Reciprocal co-immunoprecipitations show that KhpA forms a complex in cells with another KH-domain protein (KhpB/JAG/EloR). ΔkhpA and ΔkhpB mutants phenocopy each other exactly, consistent with a direct interaction. RNA-immunoprecipitation showed that KhpA/KhpB bind an overlapping set of RNAs in cells. Phosphorylation of KhpB reported previously does not affect KhpB function in the D39 progenitor background. A chromosome duplication implicated FtsA overproduction in Δpbp2b suppression. We show that cellular FtsA concentration is negatively regulated by KhpA/B at the post-transcriptional level and that FtsA overproduction is necessary and sufficient for suppression of Δpbp2b. However, increased FtsA only partially accounts for the phenotypes of ΔkhpA mutants. Together, these results suggest that multimeric KhpA/B may function as a pleiotropic RNA chaperone controlling pneumococcal cell division.
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Affiliation(s)
- Jiaqi J Zheng
- Department of Biology, Indiana University Bloomington (IUB), Bloomington, IN 47405, USA
| | - Amilcar J Perez
- Department of Biology, Indiana University Bloomington (IUB), Bloomington, IN 47405, USA
| | - Ho-Ching Tiffany Tsui
- Department of Biology, Indiana University Bloomington (IUB), Bloomington, IN 47405, USA
| | - Orietta Massidda
- Dipartimento di Scienze Chirurgiche, Università di Cagliari, 09100 Cagliari, Italy
| | - Malcolm E Winkler
- Department of Biology, Indiana University Bloomington (IUB), Bloomington, IN 47405, USA
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Makthal N, Kumaraswami M. Zinc'ing it out: zinc homeostasis mechanisms and their impact on the pathogenesis of human pathogen group A streptococcus. Metallomics 2017; 9:1693-1702. [PMID: 29043347 DOI: 10.1039/c7mt00240h] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Group A Streptococccus (GAS) is a major human pathogen that causes significant morbidity and mortality. Zinc is an essential trace element required for GAS growth, however, zinc can be toxic at excess concentrations. The bacterial strategies to maintain zinc sufficiency without incurring zinc toxicity play a crucial role in host-GAS interactions and have a significant impact on GAS pathogenesis. The host deploys nutritional immune mechanisms to retard GAS growth by causing either zinc deprivation or zinc poisoning. However, GAS overcomes the zinc-dependent host defenses and survives in the hostile environment by employing complex adaptive strategies. In this review, we describe the different host immune strategies that employ either zinc limitation or zinc toxicity in different host environments to control GAS infection. We also discuss the molecular mechanisms and machineries used by GAS to evade host nutritional defenses and establish successful infection. Emerging evidence suggests that the metal transporters are major GAS virulence factors as they compete against host nutritional immune mechanisms to acquire or expel metals and promote bacterial survival in the host. Thus, identification of GAS molecules and elucidation of the mechanisms by which GAS combats host-mediated alterations in zinc availability may lead to novel interference strategies targeting GAS metal acquisition systems.
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Affiliation(s)
- Nishanth Makthal
- Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Research Institute, and Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TX 77030, USA.
| | - Muthiah Kumaraswami
- Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Research Institute, and Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TX 77030, USA.
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31
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Metallochaperones and metalloregulation in bacteria. Essays Biochem 2017; 61:177-200. [PMID: 28487396 DOI: 10.1042/ebc20160076] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 02/23/2017] [Accepted: 02/27/2017] [Indexed: 12/21/2022]
Abstract
Bacterial transition metal homoeostasis or simply 'metallostasis' describes the process by which cells control the intracellular availability of functionally required metal cofactors, from manganese (Mn) to zinc (Zn), avoiding both metal deprivation and toxicity. Metallostasis is an emerging aspect of the vertebrate host-pathogen interface that is defined by a 'tug-of-war' for biologically essential metals and provides the motivation for much recent work in this area. The host employs a number of strategies to starve the microbial pathogen of essential metals, while for others attempts to limit bacterial infections by leveraging highly competitive metals. Bacteria must be capable of adapting to these efforts to remodel the transition metal landscape and employ highly specialized metal sensing transcriptional regulators, termed metalloregulatory proteins,and metallochaperones, that allocate metals to specific destinations, to mediate this adaptive response. In this essay, we discuss recent progress in our understanding of the structural mechanisms and metal specificity of this adaptive response, focusing on energy-requiring metallochaperones that play roles in the metallocofactor active site assembly in metalloenzymes and metallosensors, which govern the systems-level response to metal limitation and intoxication.
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