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Fernández-Otal Á, Guío J, Sarasa-Buisan C, Peleato ML, Fillat MF, Lanas Á, Bes MT. Functional characterization of Fur from the strict anaerobe Clostridioides difficile provides insight into its redox-driven regulatory capacity. FEBS J 2024; 291:3604-3627. [PMID: 38775144 DOI: 10.1111/febs.17156] [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: 12/01/2023] [Revised: 02/06/2024] [Accepted: 04/29/2024] [Indexed: 08/15/2024]
Abstract
Clostridioides (formerly Clostridium) difficile is a leading cause of infectious diarrhea associated with antibiotic therapy. The ability of this anaerobic pathogen to acquire enough iron to proliferate under iron limitation conditions imposed by the host largely determines its pathogenicity. However, since high intracellular iron catalyzes formation of deleterious reactive hydroxyl radicals, iron uptake is tightly regulated at the transcriptional level by the ferric uptake regulator Fur. Several studies relate lacking a functional fur gene in C. difficile cells to higher oxidative stress sensitivity, colonization defect and less toxigenicity, although Fur does not appear to directly regulate either oxidative stress response genes or pathogenesis genes. In this work, we report the functional characterization of C. difficile Fur and describe an additional oxidation sensing Fur-mediated mechanism independent of iron, which affects Fur DNA-binding. Using electrophoretic mobility shift assays, we show that Fur binding to the promoters of fur, feoA and fldX genes, identified as iron and Fur-regulated genes in vivo, is specific and does not require co-regulator metal under reducing conditions. Fur treatment with H2O2 produces dose-dependent soluble high molecular weight species unable to bind to target promoters. Moreover, Fur oligomers are dithiotreitol sensitive, highlighting the importance of some interchain disulfide bond(s) for Fur oligomerization, and hence for activity. Additionally, the physiological electron transport chain NADPH-thioredoxin reductase/thioredoxin from Escherichia coli reduces inactive oligomerized C. difficile Fur that recovers activity. In conjunction with available transcriptomic data, these results suggest a previously underappreciated complexity in the control of some members of the Fur regulon that is based on Fur redox properties and might be fundamental for the adaptive response of C. difficile during infection.
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Affiliation(s)
- Ángela Fernández-Otal
- Department of Biochemistry & Molecular and Cellular Biology, University of Zaragoza, Spain
- Institute for Biocomputation and Physics of Complex Systems (BIFI), Mariano Esquillor (Edif. I+D), Zaragoza, Spain
- Aragon Institute for Health Research (IIS Aragón), Zaragoza, Spain
| | - Jorge Guío
- Department of Biochemistry & Molecular and Cellular Biology, University of Zaragoza, Spain
- Institute for Biocomputation and Physics of Complex Systems (BIFI), Mariano Esquillor (Edif. I+D), Zaragoza, Spain
| | - Cristina Sarasa-Buisan
- Department of Biochemistry & Molecular and Cellular Biology, University of Zaragoza, Spain
- Institute for Biocomputation and Physics of Complex Systems (BIFI), Mariano Esquillor (Edif. I+D), Zaragoza, Spain
| | - M Luisa Peleato
- Department of Biochemistry & Molecular and Cellular Biology, University of Zaragoza, Spain
- Institute for Biocomputation and Physics of Complex Systems (BIFI), Mariano Esquillor (Edif. I+D), Zaragoza, Spain
| | - María F Fillat
- Department of Biochemistry & Molecular and Cellular Biology, University of Zaragoza, Spain
- Institute for Biocomputation and Physics of Complex Systems (BIFI), Mariano Esquillor (Edif. I+D), Zaragoza, Spain
| | - Ángel Lanas
- Aragon Institute for Health Research (IIS Aragón), Zaragoza, Spain
- Digestive Diseases Service, University Clinic Hospital Lozano Blesa, Zaragoza, Spain
- CIBERehd, Madrid, Spain
| | - M Teresa Bes
- Department of Biochemistry & Molecular and Cellular Biology, University of Zaragoza, Spain
- Institute for Biocomputation and Physics of Complex Systems (BIFI), Mariano Esquillor (Edif. I+D), Zaragoza, Spain
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2
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Wang J, Zou Z, Hu M, Shan X, Zhang Y, Miao Y, Zhang X, Islam N, Hu Q. Riemerella anatipestifer UvrC is required for iron utilization, biofilm formation and virulence. Avian Pathol 2024; 53:247-256. [PMID: 38420684 DOI: 10.1080/03079457.2024.2317431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 02/06/2024] [Indexed: 03/02/2024]
Abstract
UvrC is a subunit of excinuclease ABC, which mediates nucleotide excision repair (NER) in bacteria. Our previous studies showed that transposon Tn4531 insertion in the UvrC encoding gene Riean_1413 results in reduced biofilm formation by Riemerella anatipestifer strain CH3 and attenuates virulence of strain YZb1. In this study, whether R. anatipestifer UvrC has some biological functions other than NER was investigated. Firstly, the uvrC of R. anatipestifer strain Yb2 was in-frame deleted by homologous recombination, generating deletion mutant ΔuvrC, and its complemented strain cΔuvrC was constructed based on Escherichia coli - R. anatipestifer shuttle plasmid pRES. Compared to the wild-type (WT) R. anatipestifer strain Yb2, uvrC deleted mutant ΔuvrC significantly reduced biofilm formation, tolerance to H2O2- and HOCl-induced oxidative stress, iron utilization, and adhesion to and invasion of duck embryonic hepatocytes, but not its growth curve and proteolytic activity. In addition, animal experiments showed that the LD50 value of ΔuvrC in ducklings was about 13-fold higher than that of the WT, and the bacterial loads in ΔuvrC infected ducklings were significantly lower than those in Yb2-infected ducklings, indicating uvrC deletion in R. anatipestifer attenuated virulence. Taken together, the results of this study indicate that R. anatipestifer UvrC is required for iron utilization, biofilm formation, oxidative stress tolerance and virulence of strain Yb2, demonstrating multiple functions of UvrC.RESEARCH HIGHLIGHTSDeletion of uvrC in R. anatipestfer Yb2 significantly reduced its biofilm formation.uvrC deletion led to reduced tolerance to H2O2- and HOCl-induced oxidative stress.The iron utilization of uvrC deleted mutant was significantly reduced.The uvrC deletion in R. anatipestifer Yb2 attenuated its virulence.
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Affiliation(s)
- Jialing Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People's Republic of China
| | - Zuocheng Zou
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People's Republic of China
| | - Mengmeng Hu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People's Republic of China
| | - Xinggen Shan
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People's Republic of China
| | - Ying Zhang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People's Republic of China
| | - Yiqin Miao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People's Republic of China
| | - XiaoYing Zhang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People's Republic of China
| | - Nazrul Islam
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People's Republic of China
| | - Qinghai Hu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People's Republic of China
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3
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Bak DW, Weerapana E. Proteomic strategies to interrogate the Fe-S proteome. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119791. [PMID: 38925478 DOI: 10.1016/j.bbamcr.2024.119791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 05/23/2024] [Accepted: 06/19/2024] [Indexed: 06/28/2024]
Abstract
Iron‑sulfur (Fe-S) clusters, inorganic cofactors composed of iron and sulfide, participate in numerous essential redox, non-redox, structural, and regulatory biological processes within the cell. Though structurally and functionally diverse, the list of all proteins in an organism capable of binding one or more Fe-S clusters is referred to as its Fe-S proteome. Importantly, the Fe-S proteome is highly dynamic, with continuous cluster synthesis and delivery by complex Fe-S cluster biogenesis pathways. This cluster delivery is balanced out by processes that can result in loss of Fe-S cluster binding, such as redox state changes, iron availability, and oxygen sensitivity. Despite continued expansion of the Fe-S protein catalogue, it remains a challenge to reliably identify novel Fe-S proteins. As such, high-throughput techniques that can report on native Fe-S cluster binding are required to both identify new Fe-S proteins, as well as characterize the in vivo dynamics of Fe-S cluster binding. Due to the recent rapid growth in mass spectrometry, proteomics, and chemical biology, there has been a host of techniques developed that are applicable to the study of native Fe-S proteins. This review will detail both the current understanding of the Fe-S proteome and Fe-S cluster biology as well as describing state-of-the-art proteomic strategies for the study of Fe-S clusters within the context of a native proteome.
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Affiliation(s)
- Daniel W Bak
- Department of Chemistry, Boston College, Chestnut Hill, MA, United States of America.
| | - Eranthie Weerapana
- Department of Chemistry, Boston College, Chestnut Hill, MA, United States of America.
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4
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Hahn V, Zühlke D, Winter H, Landskron A, Bernhardt J, Sievers S, Schmidt M, von Woedtke T, Riedel K, Kolb JF. Proteomic profiling of antibiotic-resistant Escherichia coli GW-AmxH19 isolated from hospital wastewater treated with physical plasma. Proteomics 2024:e2300494. [PMID: 38644344 DOI: 10.1002/pmic.202300494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 03/29/2024] [Accepted: 04/04/2024] [Indexed: 04/23/2024]
Abstract
Microorganisms which are resistant to antibiotics are a global threat to the health of humans and animals. Wastewater treatment plants are known hotspots for the dissemination of antibiotic resistances. Therefore, novel methods for the inactivation of pathogens, and in particular antibiotic-resistant microorganisms (ARM), are of increasing interest. An especially promising method could be a water treatment by physical plasma which provides charged particles, electric fields, UV-radiation, and reactive species. The latter are foremost responsible for the antimicrobial properties of plasma. Thus, with plasma it might be possible to reduce the amount of ARM and to establish this technology as additional treatment stage for wastewater remediation. However, the impact of plasma on microorganisms beyond a mere inactivation was analyzed in more detail by a proteomic approach. Therefore, Escherichia coli GW-AmxH19, isolated from hospital wastewater in Germany, was used. The bacterial solution was treated by a plasma discharge ignited between each of four pins and the liquid surface. The growth of E. coli and the pH-value decreased during plasma treatment in comparison with the untreated control. Proteome and antibiotic resistance profile were analyzed. Concentrations of nitrite and nitrate were determined as long-lived indicative products of a transient chemistry associated with reactive nitrogen species (RNS). Conversely, hydrogen peroxide served as indicator for reactive oxygen species (ROS). Proteome analyses revealed an oxidative stress response as a result of plasma-generated RNS and ROS as well as a pH-balancing reaction as key responses to plasma treatment. Both, the generation of reactive species and a decreased pH-value is characteristic for plasma-treated solutions. The plasma-mediated changes of the proteome are discussed also in comparison with the Gram-positive bacterium Bacillus subtilis. Furthermore, no effect of the plasma treatment, on the antibiotic resistance of E. coli, was determined under the chosen conditions. The knowledge about the physiological changes of ARM in response to plasma is of fundamental interest to understand the molecular basis for the inactivation. This will be important for the further development and implementation of plasma in wastewater remediation.
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Affiliation(s)
- Veronika Hahn
- Leibniz Institute for Plasma Science and Technology (INP), Greifswald, Germany
| | - Daniela Zühlke
- Institute of Marine Biotechnology, Greifswald, Germany
- Department of Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Hauke Winter
- Leibniz Institute for Plasma Science and Technology (INP), Greifswald, Germany
- Department of Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Annchristin Landskron
- Leibniz Institute for Plasma Science and Technology (INP), Greifswald, Germany
- Department of Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Jörg Bernhardt
- Department of Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Susanne Sievers
- Department of Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Michael Schmidt
- Leibniz Institute for Plasma Science and Technology (INP), Greifswald, Germany
| | - Thomas von Woedtke
- Leibniz Institute for Plasma Science and Technology (INP), Greifswald, Germany
- Institute for Hygiene and Environmental Medicine, Greifswald University Medicine, Greifswald, Germany
| | - Katharina Riedel
- Institute of Marine Biotechnology, Greifswald, Germany
- Department of Microbial Physiology and Molecular Biology, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Juergen F Kolb
- Leibniz Institute for Plasma Science and Technology (INP), Greifswald, Germany
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Purcell AG, Fontenot CR, Ding H. Iron-sulfur cluster assembly scaffold protein IscU is required for activation of ferric uptake regulator (Fur) in Escherichiacoli. J Biol Chem 2024; 300:107142. [PMID: 38452854 PMCID: PMC11001641 DOI: 10.1016/j.jbc.2024.107142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 02/20/2024] [Accepted: 02/28/2024] [Indexed: 03/09/2024] Open
Abstract
It was generally postulated that when intracellular free iron content is elevated in bacteria, the ferric uptake regulator (Fur) binds its corepressor a mononuclear ferrous iron to regulate intracellular iron homeostasis. However, the proposed iron-bound Fur had not been identified in any bacteria. In previous studies, we have demonstrated that Escherichia coli Fur binds a [2Fe-2S] cluster in response to elevation of intracellular free iron content and that binding of the [2Fe-2S] cluster turns on Fur as an active repressor to bind a specific DNA sequence known as the Fur-box. Here we find that the iron-sulfur cluster assembly scaffold protein IscU is required for the [2Fe-2S] cluster assembly in Fur, as deletion of IscU inhibits the [2Fe-2S] cluster assembly in Fur and prevents activation of Fur as a repressor in E. coli cells in response to elevation of intracellular free iron content. Additional studies reveal that IscU promotes the [2Fe-2S] cluster assembly in apo-form Fur and restores its Fur-box binding activity in vitro. While IscU is also required for the [2Fe-2S] cluster assembly in the Haemophilus influenzae Fur in E. coli cells, deletion of IscU does not significantly affect the [2Fe-2S] cluster assembly in the E. coli ferredoxin and siderophore-reductase FhuF. Our results suggest that IscU may have a unique role for the [2Fe-2S] cluster assembly in Fur and that regulation of intracellular iron homeostasis is closely coupled with iron-sulfur cluster biogenesis in E. coli.
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Affiliation(s)
- Aidan G Purcell
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Chelsey R Fontenot
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Huangen Ding
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, USA.
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6
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Fontenot CR, Ding H. The C-terminal domain of the ferric uptake regulator (Fur) binds a [2Fe-2S] cluster to sense the intracellular free iron content in Escherichia coli. Biometals 2023; 36:1285-1294. [PMID: 37344741 DOI: 10.1007/s10534-023-00517-6] [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: 04/02/2023] [Accepted: 06/14/2023] [Indexed: 06/23/2023]
Abstract
Escherichia coli ferric uptake regulator (Fur) binds a [2Fe-2S] cluster, not a mononuclear iron, when the intracellular free iron content is elevated in E. coli cells. Here we report that the C-terminal domain (residues 83-148) of E. coli Fur (Fur-CTD) is sufficient to bind the [2Fe-2S] cluster in response to elevation of the intracellular free iron content in E. coli cells. Deletion of gene fur in E. coli cells increases the intracellular free iron content and promotes the [2Fe-2S] cluster binding in the Fur-CTD in the cells grown in LB medium under aerobic growth conditions. When the Fur-CTD is expressed in wild type E. coli cells grown in M9 medium supplemented with increasing concentrations of iron, the Fur-CTD also progressively binds a [2Fe-2S] cluster with a maximum occupancy of about 36%. Like the E. coli Fur-CTD, the CTD of the Haemophilus influenzae Fur can also bind a [2Fe-2S] cluster in wild type E. coli cells grown in M9 medium supplemented with increasing concentrations of iron, indicating that binding of the [2Fe-2S] cluster in the C-terminal domain is highly conserved among Fur proteins. The results suggest that the Fur-CTD can be used as a physiological probe to assess the intracellular free iron content in bacteria.
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Affiliation(s)
- Chelsey R Fontenot
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Huangen Ding
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA.
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7
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Wang NE, Courcelle EJ, Coltman SM, Spolek RL, Courcelle J, Courcelle CT. Manganese transporters regulate the resumption of replication in hydrogen peroxide-stressed Escherichia coli. Biometals 2023; 36:1361-1376. [PMID: 37493920 DOI: 10.1007/s10534-023-00523-8] [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: 04/18/2023] [Accepted: 07/06/2023] [Indexed: 07/27/2023]
Abstract
Following hydrogen peroxide treatment, ferrous iron (Fe2+) is oxidized to its ferric form (Fe3+), stripping it from and inactivating iron-containing proteins. Many mononuclear iron enzymes can be remetallated by manganese to restore function, while other enzymes specifically utilize manganese as a cofactor, having redundant activities that compensate for iron-depleted counterparts. DNA replication relies on one or more iron-dependent protein(s) as synthesis abates in the presence of hydrogen peroxide and requires manganese in the medium to resume. Here, we show that manganese transporters regulate the ability to resume replication following oxidative challenge in Escherichia coli. The absence of the primary manganese importer, MntH, impairs the ability to resume replication; whereas deleting the manganese exporter, MntP, or transporter regulator, MntR, dramatically increases the rate of recovery. Unregulated manganese import promoted recovery even in the absence of Fur, which maintains iron homeostasis. Similarly, replication was not restored in oxyR mutants, which cannot upregulate manganese import following hydrogen peroxide stress. Taken together, the results define a central role for manganese transport in restoring replication following oxidative stress.
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Affiliation(s)
- Natalie E Wang
- Department of Biology, Portland State University, Portland, OR, 97201, USA
| | | | - Samantha M Coltman
- Department of Biology, Portland State University, Portland, OR, 97201, USA
| | - Raymond L Spolek
- Department of Biology, Portland State University, Portland, OR, 97201, USA
| | - Justin Courcelle
- Department of Biology, Portland State University, Portland, OR, 97201, USA.
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Gray E, Stewart MYY, Hanwell L, Crack JC, Devine R, Stevenson CEM, Volbeda A, Johnston AWB, Fontecilla-Camps JC, Hutchings MI, Todd JD, Le Brun NE. Stabilisation of the RirA [4Fe-4S] cluster results in loss of iron-sensing function. Chem Sci 2023; 14:9744-9758. [PMID: 37736639 PMCID: PMC10510648 DOI: 10.1039/d3sc03020b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 08/21/2023] [Indexed: 09/23/2023] Open
Abstract
RirA is a global iron regulator in diverse Alphaproteobacteria that belongs to the Rrf2 superfamily of transcriptional regulators, which can contain an iron-sulfur (Fe-S) cluster. Under iron-replete conditions, RirA contains a [4Fe-4S] cluster, enabling high-affinity binding to RirA-regulated operator sequences, thereby causing the repression of cellular iron uptake. Under iron deficiency, one of the cluster irons dissociates, generating an unstable [3Fe-4S] form that subsequently degrades to a [2Fe-2S] form and then to apo RirA, resulting in loss of high-affinity DNA-binding. The cluster is coordinated by three conserved cysteine residues and an unknown fourth ligand. Considering the lability of one of the irons and the resulting cluster fragility, we hypothesized that the fourth ligand may not be an amino acid residue. To investigate this, we considered that the introduction of an amino acid residue that could coordinate the cluster might stabilize it. A structural model of RirA, based on the Rrf2 family nitrosative stress response regulator NsrR, highlighted residue 8, an Asn in the RirA sequence, as being appropriately positioned to coordinate the cluster. Substitution of Asn8 with Asp, the equivalent, cluster-coordinating residue of NsrR, or with Cys, resulted in proteins that contained a [4Fe-4S] cluster, with N8D RirA exhibiting spectroscopic properties very similar to NsrR. The variant proteins retained the ability to bind RirA-regulated DNA, and could still act as repressors of RirA-regulated genes in vivo. However, they were significantly more stable than wild-type RirA when exposed to O2 and/or low iron. Importantly, they exhibited reduced capacity to respond to cellular iron levels, even abolished in the case of the N8D version, and thus were no longer iron sensing. This work demonstrates the importance of cluster fragility for the iron-sensing function of RirA, and more broadly, how a single residue substitution can alter cluster coordination and functional properties in the Rrf2 superfamily of regulators.
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Affiliation(s)
- Elizabeth Gray
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia Norwich Research Park Norwich NR4 7TJ UK +44 (0)1603 592003 +44 (0)1603 592699
| | - Melissa Y Y Stewart
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia Norwich Research Park Norwich NR4 7TJ UK +44 (0)1603 592003 +44 (0)1603 592699
| | - Libby Hanwell
- School of Biological Sciences, University of East Anglia Norwich Research Park Norwich NR4 7TJ UK
| | - Jason C Crack
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia Norwich Research Park Norwich NR4 7TJ UK +44 (0)1603 592003 +44 (0)1603 592699
| | - Rebecca Devine
- Department of Molecular Microbiology, John Innes Centre Norwich Research Park Norwich NR4 7UH UK
| | - Clare E M Stevenson
- Department of Molecular Microbiology, John Innes Centre Norwich Research Park Norwich NR4 7UH UK
| | - Anne Volbeda
- Metalloproteins Unit, Institut de Biologie Structurale, CEA, CNRS, Université Grenoble-Alpes 71, Avenue des Martyrs, CS 10090 38044 Grenoble Cedex 9 France
| | - Andrew W B Johnston
- School of Biological Sciences, University of East Anglia Norwich Research Park Norwich NR4 7TJ UK
| | - Juan C Fontecilla-Camps
- Metalloproteins Unit, Institut de Biologie Structurale, CEA, CNRS, Université Grenoble-Alpes 71, Avenue des Martyrs, CS 10090 38044 Grenoble Cedex 9 France
| | - Matthew I Hutchings
- Department of Molecular Microbiology, John Innes Centre Norwich Research Park Norwich NR4 7UH UK
| | - Jonathan D Todd
- School of Biological Sciences, University of East Anglia Norwich Research Park Norwich NR4 7TJ UK
| | - Nick E Le Brun
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia Norwich Research Park Norwich NR4 7TJ UK +44 (0)1603 592003 +44 (0)1603 592699
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9
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Abanoz-Seçgin B, Otur Ç, Okay S, Kurt-Kızıldoğan A. The regulatory role of Fur-encoding SCLAV_3199 in iron homeostasis in Streptomyces clavuligerus. Gene 2023:147594. [PMID: 37364696 DOI: 10.1016/j.gene.2023.147594] [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: 03/14/2023] [Revised: 06/09/2023] [Accepted: 06/23/2023] [Indexed: 06/28/2023]
Abstract
Iron homeostasis is strictly regulated by complex cascades connected with secondary metabolism in bacteria. Ferric uptake regulators ('Fur's), siderophores, efflux systems, and two-component signal transduction systems are the leading players in response stimuli. However, these regulatory mechanisms remain to be elucidated in Streptomyces clavuligerus. Our study focused on unraveling a possible role of SCLAV_3199 which encodes a Fur family transcriptional regulator, particularly in iron regulation and at the global level in this species. We deleted the SCLAV_3199 gene in S. clavuligerus and compared gene expression differences with the wild-type strain based on iron availability by RNA-seq. We found a potential regulatory effect of SCLAV_3199 on many transcriptional regulators and transporters. Besides, the genes encoding iron sulfur binding proteins were overexpressed in the mutant in the presence of iron. Notably, catechol (SCLAV_5397), and hydroxamate-type (SCLAV_1952, SCLAV_4680) siderophore-related genes were upregulated in the mutant strain in iron scarcity. Concomitantly, S. clavuligerus Δ3199 produced 1.65 and 1.9 times more catechol and hydroxamate-type siderophores, respectively, than that of the wild type strain under iron depletion. Iron containing chemically defined medium did not favor antibiotic production in S. clavuligerus Δ3199 while fermentation in starch-asparagine medium led to improved cephamycin C (2.23-fold) and clavulanic acid (2.56-fold) production in the mutant compared to the control. However, better tunicamycin yield (2.64-fold) was obtained in trypticase soy broth-grown cultures of S. clavuligerus Δ3199. Our findings demonstrate that the SCLAV_3199 gene plays a significant role in regulating both iron homeostasis and secondary metabolite biosynthesis in S. clavuligerus.
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Affiliation(s)
- Büşra Abanoz-Seçgin
- Department of Agricultural Biotechnology, Ondokuz Mayıs University, Samsun 55139, Türkiye
| | - Çiğdem Otur
- Department of Agricultural Biotechnology, Ondokuz Mayıs University, Samsun 55139, Türkiye
| | - Sezer Okay
- Department of Vaccine Technology, Vaccine Institute, Hacettepe University, Ankara, 06230, Türkiye
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10
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Zhong ZX, Zhou S, Liang YJ, Wei YY, Li Y, Long TF, He Q, Li MY, Zhou YF, Yu Y, Fang LX, Liao XP, Kreiswirth BN, Chen L, Ren H, Liu YH, Sun J. Natural flavonoids disrupt bacterial iron homeostasis to potentiate colistin efficacy. SCIENCE ADVANCES 2023; 9:eadg4205. [PMID: 37294761 PMCID: PMC10256158 DOI: 10.1126/sciadv.adg4205] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 05/04/2023] [Indexed: 06/11/2023]
Abstract
In the face of the alarming rise in global antimicrobial resistance, only a handful of novel antibiotics have been developed in recent decades, necessitating innovations in therapeutic strategies to fill the void of antibiotic discovery. Here, we established a screening platform mimicking the host milieu to select antibiotic adjuvants and found three catechol-type flavonoids-7,8-dihydroxyflavone, myricetin, and luteolin-prominently potentiating the efficacy of colistin. Further mechanistic analysis demonstrated that these flavonoids are able to disrupt bacterial iron homeostasis through converting ferric iron to ferrous form. The excessive intracellular ferrous iron modulated the membrane charge of bacteria via interfering the two-component system pmrA/pmrB, thereby promoting the colistin binding and subsequent membrane damage. The potentiation of these flavonoids was further confirmed in an in vivo infection model. Collectively, the current study provided three flavonoids as colistin adjuvant to replenish our arsenals for combating bacterial infections and shed the light on the bacterial iron signaling as a promising target for antibacterial therapies.
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Affiliation(s)
- Zi-xing Zhong
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Shuang Zhou
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Yu-jiao Liang
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Yi-yang Wei
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Yan Li
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Teng-fei Long
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Qian He
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Meng-yuan Li
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Yu-feng Zhou
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Yang Yu
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Liang-xing Fang
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Xiao-ping Liao
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Barry N. Kreiswirth
- Hackensack-Meridian Health Center for Discovery and Innovation, Nutley, NJ, USA
| | - Liang Chen
- Hackensack-Meridian Health Center for Discovery and Innovation, Nutley, NJ, USA
| | - Hao Ren
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
| | - Ya-hong Liu
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, PR China
| | - Jian Sun
- Guangdong Laboratory for Lingnan Modern Agriculture, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics, Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, PR China
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11
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Yu M, Tang Y, Lu L, Kong W, Ye J. CysB Is a Key Regulator of the Antifungal Activity of Burkholderia pyrrocinia JK-SH007. Int J Mol Sci 2023; 24:ijms24098067. [PMID: 37175772 PMCID: PMC10179380 DOI: 10.3390/ijms24098067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 04/19/2023] [Accepted: 04/28/2023] [Indexed: 05/15/2023] Open
Abstract
Burkholderia pyrrocinia JK-SH007 can effectively control poplar canker caused by pathogenic fungi. Its antifungal mechanism remains to be explored. Here, we characterized the functional role of CysB in B. pyrrocinia JK-SH007. This protein was shown to be responsible for the synthesis of cysteine and the siderophore ornibactin, as well as the antifungal activity of B. pyrrocinia JK-SH007. We found that deletion of the cysB gene reduced the antifungal activity and production of the siderophore ornibactin in B. pyrrocinia JK-SH007. However, supplementation with cysteine largely restored these two abilities in the mutant. Further global transcriptome analysis demonstrated that the amino acid metabolic pathway was significantly affected and that some sRNAs were significantly upregulated and targeted the iron-sulfur metabolic pathway by TargetRNA2 prediction. Therefore, we suggest that, in B. pyrrocinia JK-SH007, CysB can regulate the expression of genes related to Fe-S clusters in the iron-sulfur metabolic pathway to affect the antifungal activity of B. pyrrocinia JK-SH007. These findings provide new insights into the various biological functions regulated by CysB in B. pyrrocinia JK-SH007 and the relationship between iron-sulfur metabolic pathways and fungal inhibitory substances. Additionally, they lay the foundation for further investigation of the main antagonistic substances of B. pyrrocinia JK-SH007.
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Affiliation(s)
- Meng Yu
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
| | - Yuwei Tang
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
| | - Lanxiang Lu
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
| | - Weiliang Kong
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
| | - Jianren Ye
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
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12
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Steingard CH, Helmann JD. Meddling with Metal Sensors: Fur-Family Proteins as Signaling Hubs. J Bacteriol 2023; 205:e0002223. [PMID: 37010421 PMCID: PMC10127796 DOI: 10.1128/jb.00022-23] [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: 04/04/2023] Open
Abstract
The ferric uptake regulator (Fur) protein is the founding member of the FUR superfamily of metalloregulatory proteins that control metal homeostasis in bacteria. FUR proteins regulate metal homeostasis in response to the binding of iron (Fur), zinc (Zur), manganese (Mur), or nickel (Nur). FUR family proteins are generally dimers in solution, but the DNA-bound complex can involve a single dimer, a dimer-of-dimers, or an extended array of bound protein. Elevated FUR levels due to changes in cell physiology increase DNA occupancy and may also kinetically facilitate protein dissociation. Interactions between FUR proteins and other regulators are commonplace, often including cooperative and competitive DNA-binding interactions within the regulatory region. Further, there are many emerging examples of allosteric regulators that interact directly with FUR family proteins. Here, we focus on newly uncovered examples of allosteric regulation by diverse Fur antagonists (Escherichia coli YdiV/SlyD, Salmonella enterica EIIANtr, Vibrio parahaemolyticus FcrX, Acinetobacter baumannii BlsA, Bacillus subtilis YlaN, and Pseudomonas aeruginosa PacT) as well as one Zur antagonist (Mycobacterium bovis CmtR). Small molecules and metal complexes may also serve as regulatory ligands, with examples including heme binding to Bradyrhizobium japonicum Irr and 2-oxoglutarate binding to Anabaena FurA. How these protein-protein and protein-ligand interactions act in conjunction with regulatory metal ions to facilitate signal integration is an active area of investigation.
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Affiliation(s)
| | - John D. Helmann
- Department of Microbiology, Cornell University, Ithaca, New York, USA
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13
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Fontenot CR, Ding H. Ferric uptake regulator (Fur) binds a [2Fe-2S] cluster to regulate intracellular iron homeostasis in Escherichia coli. J Biol Chem 2023; 299:104748. [PMID: 37100285 DOI: 10.1016/j.jbc.2023.104748] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 04/17/2023] [Accepted: 04/18/2023] [Indexed: 04/28/2023] Open
Abstract
Intracellular iron homeostasis in bacteria is primarily regulated by Ferric uptake regulator (Fur). It has been postulated that when intracellular free iron content is elevated, Fur binds ferrous iron to down-regulate the genes for iron uptake. However, the iron-bound Fur had not been identified in any bacteria until we recently found that Escherichia coli Fur binds a [2Fe-2S] cluster, but not a mononuclear iron, in E. coli mutant cells that hyperaccumulate intracellular free iron. Here we report that E. coli Fur also binds a [2Fe-2S] cluster in wild type E. coli cells grown in M9 medium supplemented with increasing concentrations of iron under aerobic growth conditions. Additionally, we find that binding of the [2Fe-2S] cluster in Fur turns on its binding activity for specific DNA sequences known as the Fur-box, and that removal of the [2Fe-2S] cluster from Fur eliminates its Fur-box binding activity. Mutation of the conserved cysteine residues Cys-93 and Cys-96 to Ala in Fur results in the Fur mutants that fail to bind the [2Fe-2S] cluster, have a diminished binding activity for the Fur-box in vitro, and are inactive to complement the function of Fur in vivo. Our results suggest that Fur binds a [2Fe-2S] cluster to regulate intracellular iron homeostasis in response to elevation of intracellular free iron content in E. coli cells.
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Affiliation(s)
- Chelsey R Fontenot
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Huangen Ding
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
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14
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Moreau PL. Regulation of phosphate starvation-specific responses in Escherichia coli. MICROBIOLOGY (READING, ENGLAND) 2023; 169. [PMID: 36972330 DOI: 10.1099/mic.0.001312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
Toxic agents added into the medium of rapidly growing Escherichia coli induce specific stress responses through the activation of specialized transcription factors. Each transcription factor and downstream regulon (e.g. SoxR) are linked to a unique stress (e.g. superoxide stress). Cells starved of phosphate induce several specific stress regulons during the transition to stationary phase when the growth rate is steadily declining. Whereas the regulatory cascades leading to the expression of specific stress regulons are well known in rapidly growing cells stressed by toxic products, they are poorly understood in cells starved of phosphate. The intent of this review is to both describe the unique mechanisms of activation of specialized transcription factors and discuss signalling cascades leading to the induction of specific stress regulons in phosphate-starved cells. Finally, I discuss unique defence mechanisms that could be induced in cells starved of ammonium and glucose.
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Affiliation(s)
- Patrice L Moreau
- Laboratoire Chimie Bactérienne, LCB-UMR 7283, Institut Microbiologie Méditerranée, CNRS/Université Aix-Marseille, Marseille, France
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15
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Li J, Wu Z, Hou Y, Zhang YA, Zhou Y. Fur functions as an activator of T6SS-mediated bacterial dominance and virulence in Aeromonas hydrophila. Front Microbiol 2023; 13:1099611. [PMID: 36845974 PMCID: PMC9944043 DOI: 10.3389/fmicb.2022.1099611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 12/28/2022] [Indexed: 02/11/2023] Open
Abstract
Aeromonas hydrophila, a ubiquitous bacterium in aquatic habitats with broad host ranges, has earned the nickname of a 'Jack-of-all-trades'. However, there is still a limited understanding of the mechanism of how this bacterium fit the competition with other species in dynamic surroundings. The type VI secretion system (T6SS) is macromolecular machinery found in Gram-negative bacteria's cell envelope that is responsible for bacterial killing and/or pathogenicity toward different host cells. In this study, the depression of A. hydrophila T6SS under iron-limiting conditions was detected. The ferric uptake regulator (Fur) was then found to act as an activator of T6SS by directly binding to the Fur box region in vipA promoter in the T6SS gene cluster. The transcription of vipA was repressed in Δfur. Moreover, the inactivation of Fur resulted in considerable defects in the interbacterial competition activity and pathogenicity of A. hydrophila in vitro and in vivo. These findings provide the first direct evidence that Fur positively regulates the expression and functional activity of T6SS in Gram-negative bacteria and will help to understand the fascinating mechanism of competitive advantage for A. hydrophila in different ecological niches.
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Affiliation(s)
- Jihong Li
- State Key Laboratory of Agricultural Microbiology, College of Fisheries, Huazhong Agricultural University, Wuhan, China,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China,Department of Microbiology and Immunology, Medical College, China Three Gorges University, Yichang, China,Shenzhen Institute of Nutrition and Health, Huazhong Agricultural University, Wuhan, China
| | - Zhihao Wu
- State Key Laboratory of Agricultural Microbiology, College of Fisheries, Huazhong Agricultural University, Wuhan, China
| | - Yuting Hou
- State Key Laboratory of Agricultural Microbiology, College of Fisheries, Huazhong Agricultural University, Wuhan, China
| | - Yong-An Zhang
- State Key Laboratory of Agricultural Microbiology, College of Fisheries, Huazhong Agricultural University, Wuhan, China,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China,Hubei Hongshan Laboratory, Wuhan, China,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China,Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Wuhan, China,*Correspondence: Yong-An Zhang,
| | - Yang Zhou
- State Key Laboratory of Agricultural Microbiology, College of Fisheries, Huazhong Agricultural University, Wuhan, China,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China,Shenzhen Institute of Nutrition and Health, Huazhong Agricultural University, Wuhan, China,Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Wuhan, China,Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China,Yang Zhou,
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16
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Brawley H, Kreinbrink AC, Hierholzer JD, Vali SW, Lindahl PA. Labile Iron Pool of Isolated Escherichia coli Cytosol Likely Includes Fe-ATP and Fe-Citrate but not Fe-Glutathione or Aqueous Fe. J Am Chem Soc 2023; 145:2104-2117. [PMID: 36661842 PMCID: PMC9896560 DOI: 10.1021/jacs.2c06625] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Indexed: 01/21/2023]
Abstract
The existence of labile iron pools (LFePs) in biological systems has been recognized for decades, but their chemical composition remains uncertain. Here, the LFeP in cytosol from Escherichia coli was investigated. Mössbauer spectra of whole vs lysed cells indicated significant degradation of iron-sulfur clusters (ISCs), even using an unusually gentle lysis procedure; this demonstrated the fragility of ISCs. Moreover, the released iron contributed to the non-heme high-spin Fe(II) species in the cell, which likely included the LFeP. Cytosol batches isolated from cells grown with different levels of iron supplementation were passed through a 3 kDa cutoff membrane, and resulting flow-through-solutions (FTSs) were subjected to SEC-ICP-MS. Mössbauer spectroscopy was used to evaluate the oxidation states of standards. FTSs exhibited iron-detected peaks likely due to different forms of Fe-citrate and Fe-nucleotide triphosphate complexes. Fe-Glutathione (GSH) complexes were not detected using physiological concentrations of GSH mixed with either Fe(II) or Fe(III); Fe(II)-GSH was concluded not to be a significant component of the LFeP in E. coli under physiological conditions. Aqueous iron was also not present in significant concentrations in isolated cytosol and is unlikely a major component of the pool. Fe appeared to bind ATP more tightly than citrate, but ATP also hydrolyzed on the timescale of tens of hours. Isolated cytosol contained excess ligands that coordinated the added Fe(II) and Fe(III). The LFeP in healthy metabolically active cells is undoubtedly dominated by the Fe(II) state, but the LFeP is redox-active such that a fraction might be present as stable and soluble Fe(III) complexes especially under oxidatively stressed cellular conditions.
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Affiliation(s)
- Hayley
N. Brawley
- Department
of Chemistry, Texas A&M University, College Station, Texas 77843-3255, United States
| | - Alexia C. Kreinbrink
- Department
of Biochemistry and Biophysics, Texas A&M
University, College
Station, Texas 77843, United States
| | - Justin D. Hierholzer
- Department
of Biochemistry and Biophysics, Texas A&M
University, College
Station, Texas 77843, United States
| | - Shaik Waseem Vali
- Department
of Biochemistry and Biophysics, Texas A&M
University, College
Station, Texas 77843, United States
| | - Paul A. Lindahl
- Department
of Chemistry, Texas A&M University, College Station, Texas 77843-3255, United States
- Department
of Biochemistry and Biophysics, Texas A&M
University, College
Station, Texas 77843, United States
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17
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Zhu W, Mei J, Zhang X, Zhou J, Xu D, Su Z, Fang S, Wang J, Zhang X, Zhu C. Photothermal Nanozyme-Based Microneedle Patch against Refractory Bacterial Biofilm Infection via Iron-Actuated Janus Ion Therapy. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2207961. [PMID: 36239263 DOI: 10.1002/adma.202207961] [Citation(s) in RCA: 60] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/03/2022] [Indexed: 06/16/2023]
Abstract
Owing to high antibiotic resistance and thermotolerance, bacterial biofilm infections (BBIs) are refractory to elimination. Iron is essential for bacterial growth and metabolism, and bacteria can thus accumulate iron from surrounding cells to maintain biofilm formation and survival. Consequently, iron deficiency in the biofilm microenvironment (BME) leads to the functional failure of innate immune cells. Herein, a novel antibiofilm strategy of iron-actuated Janus ion therapy (IJIT) is proposed to regulate iron metabolism in both bacterial biofilm and immune cells. A BME-responsive photothermal microneedle patch (FGO@MN) is synthesized by the growth of Fe3 O4 nanoparticles on graphene oxide nanosheets and then encapsulated in methacrylated hyaluronic acid needle tips. The catalytic product of ·OH by FGO@MN in BME disrupts the bacterial heat-shock proteins, coercing biofilm thermal sensitization. As synergistic mild photothermal treatment triggers iron uptake, the intracellular iron overload further induces ferroptosis-like death. Moreover, iron-nourished neutrophils around BME can be rejuvenated for reactivating the suppressed antibiofilm function. Thus, more than 95% BBIs elimination can be achieved by combining heat stress-triggered iron interference with iron-nutrient immune reactivation. Furthermore, in vivo experiments validate the scavenging of refractory BBI after 15 days, suggesting the promising perspective of IJIT in future clinical application.
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Affiliation(s)
- Wanbo Zhu
- Department of Orthopedics, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, Anhui, 230001, P. R. China
- Department of Orthopedics, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai, 200233, P. R. China
| | - Jiawei Mei
- Department of Orthopedics, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, Anhui, 230001, P. R. China
| | - Xianzuo Zhang
- Department of Orthopedics, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, Anhui, 230001, P. R. China
| | - Jun Zhou
- Department of Orthopedics, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, Anhui, 230001, P. R. China
- Department of Orthopedics, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai, 200233, P. R. China
| | - Dongdong Xu
- Department of Orthopedics, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai, 200233, P. R. China
| | - Zheng Su
- Department of Orthopedics, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, Anhui, 230001, P. R. China
| | - Shiyuan Fang
- Department of Orthopedics, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, Anhui, 230001, P. R. China
| | - Jiaxing Wang
- Department of Orthopedics, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai, 200233, P. R. China
| | - Xianlong Zhang
- Department of Orthopedics, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai, 200233, P. R. China
| | - Chen Zhu
- Department of Orthopedics, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, Anhui, 230001, P. R. China
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18
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Mu WY, Chen CH, Chen QY. Bacterium-Sculpted Porphyrin-Protein-Iron Sulfide Clusters for Distinction and Inhibition of Staphylococcus aureus. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:10385-10391. [PMID: 35980392 DOI: 10.1021/acs.langmuir.2c00964] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Microbe-catalyzed surface modification is a promising method for the production of special targeting nanomaterials. A bacterium-selective material can be obtained by investigating the microbe-catalyzed mineralization of proteins. Herein, a novel method was fabricated for the biosynthesis of FeS-decorated porphyrin-protein clusters (P-CA@BE) via E. coli (Escherichia coli)-catalyzed bio-Fe(III) reduction and bio-sulfidation of porphyrin (P), caffeic acid (CA), and protein [bovine serum albumin (BSA)] assemblies. The assembly (P-CA@BSA) was identified by spectroscopic methods. Next, the P-CA@BSA assembly was transferred into FeS-decorated porphyrin-protein clusters (P-CA@BE) catalyzed by E. coli. There are partial β-folding proteins in P-CA@BE, which selectively recognize S. aureus (Staphylococcus aureus) and show different antibacterial properties against E. coli and S. aureus. Results demonstrate that the E. coli-catalyzed mineralization of the porphyrin-protein assembly is an effective method for the biosynthesis of S. aureus-sensitive metal-protein clusters.
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Affiliation(s)
- Wei-Yu Mu
- School of Chemistry and Chemical Engineering, Jiangsu University, Xuefu Road, Jingkou District, Zhenjiang 212013, People's Republic of China
| | - Cai-Hua Chen
- School of Chemistry and Chemical Engineering, Jiangsu University, Xuefu Road, Jingkou District, Zhenjiang 212013, People's Republic of China
| | - Qiu-Yun Chen
- School of Chemistry and Chemical Engineering, Jiangsu University, Xuefu Road, Jingkou District, Zhenjiang 212013, People's Republic of China
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19
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Zik JJ, Yoon SH, Guan Z, Stankeviciute Skidmore G, Gudoor RR, Davies KM, Deutschbauer AM, Goodlett DR, Klein EA, Ryan KR. Caulobacter lipid A is conditionally dispensable in the absence of fur and in the presence of anionic sphingolipids. Cell Rep 2022; 39:110888. [PMID: 35649364 PMCID: PMC9393093 DOI: 10.1016/j.celrep.2022.110888] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/29/2022] [Accepted: 05/06/2022] [Indexed: 01/12/2023] Open
Abstract
Lipid A, the membrane-anchored portion of lipopolysaccharide (LPS), is an essential component of the outer membrane (OM) of nearly all Gram-negative bacteria. Here we identify regulatory and structural factors that together render lipid A nonessential in Caulobacter crescentus. Mutations in the ferric uptake regulator fur allow Caulobacter to survive in the absence of either LpxC, which catalyzes an early step of lipid A synthesis, or CtpA, a tyrosine phosphatase homolog we find is needed for wild-type lipid A structure and abundance. Alterations in Fur-regulated processes, rather than iron status per se, underlie the ability to survive when lipid A synthesis is blocked. Fitness of lipid A-deficient Caulobacter requires an anionic sphingolipid, ceramide phosphoglycerate (CPG), which also mediates sensitivity to the antibiotic colistin. Our results demonstrate that, in an altered regulatory landscape, anionic sphingolipids can support the integrity of a lipid A-deficient OM. Lipid A, the membrane-anchoring segment of lipopolysaccharide, is generally considered to be an essential component of the Gram-negative bacterial outer membrane. Zik et al. show that deletion of the transcriptional regulator fur and synthesis of the anionic sphingolipid ceramide phosphoglycerate enable Caulobacter crescentus to survive without lipid A.
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Affiliation(s)
- Justin J Zik
- Department of Plant & Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Sung Hwan Yoon
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, MD 21201, USA
| | - Ziqiang Guan
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | - Gabriele Stankeviciute Skidmore
- Center for Computational and Integrative Biology, Rutgers University-Camden, Camden, NJ 08102, USA; Rutgers Center for Lipid Research, Rutgers University, New Brunswick, NJ 08901, USA
| | - Ridhi R Gudoor
- Molecular Biosciences and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Karen M Davies
- Molecular Biosciences and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Adam M Deutschbauer
- Environmental Genomics & Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - David R Goodlett
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Department of Biochemistry & Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada; University of Victoria-Genome BC Proteomics Centre, Victoria, BC V8Z 7X8, Canada
| | - Eric A Klein
- Center for Computational and Integrative Biology, Rutgers University-Camden, Camden, NJ 08102, USA; Biology Department, Rutgers University-Camden, Camden, NJ 08102, USA; Rutgers Center for Lipid Research, Rutgers University, New Brunswick, NJ 08901, USA
| | - Kathleen R Ryan
- Department of Plant & Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Environmental Genomics & Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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20
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Abstract
Ecotypic diversification and its associated cooperative behaviors are frequently observed in natural microbial populations whose access to resources is often sporadic. However, the extent to which fluctuations in resource availability influence the emergence of cooperative ecotypes is not fully understood. To determine how exposure to repeated resource limitation affects the establishment and long-term maintenance of ecotypes in a structured environment, we followed 32 populations of Escherichia coli evolving to either 1-day or 10-day feast/famine cycles for 900 days. Population-level analysis revealed that compared to populations evolving to 1-day cycles, 10-day populations evolved increased biofilm density, higher parallelism in mutational targets, and increased mutation rates. As previous investigations of evolution in structured environments have identified biofilm formation as the earliest observable phenotype associated with diversification of ecotypes, we revived cultures midway through the evolutionary process and conducted additional genomic, transcriptional, and phenotypic analyses of clones isolated from these evolving populations. We found not only that 10-day feast/famine cycles support multiple ecotypes but also that these ecotypes exhibit cooperative behavior. Consistent with the black queen hypothesis, or evolution of cooperation by gene loss, transcriptomic evidence suggests the evolution of bidirectional cross-feeding behaviors based on essential resources. These results provide insight into how analogous cooperative relationships may emerge in natural microbial communities. IMPORTANCE Despite regular feast and famine conditions representing an environmental pressure that is commonly encountered by microbial communities, the evolutionary outcomes of repeated cycles of feast and famine have been less studied. By experimentally evolving initially isogenic Escherichia coli populations to 10-day feast/famine cycles, we observed rapid diversification into ecotypes with evidence of bidirectional cross-feeding on costly resources and frequency-dependent fitness. Although unidirectional cross-feeding has been repeatedly observed to evolve in laboratory culture, most investigations of bidirectional cooperative behaviors in microbial populations have been conducted in engineered communities. This work demonstrates the de novo evolution of black queen relationships in a microbial population originating from a single ancestor, providing a model for investigation of the eco-evolutionary processes leading to mutualistic cooperation.
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Fontenot CR, Ding H. Ferric uptake regulators (Fur) from Vibrio cholerae and Helicobacter pylori bind a [2Fe-2S] cluster in response to elevation of intracellular free iron content. Biometals 2022; 35:591-600. [PMID: 35353296 DOI: 10.1007/s10534-022-00390-9] [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: 01/17/2022] [Accepted: 03/14/2022] [Indexed: 11/28/2022]
Abstract
Intracellular iron homeostasis in bacteria is primarily regulated by ferric uptake regulator (Fur). Since its discovery, Fur has been assumed to bind ferrous iron and regulate expression of target genes. However, the iron-bound Fur has never been isolated from any bacteria. In previous studies, we have shown that Escherichia coli Fur and Haemophilus influenzae Fur bind a [2Fe-2S] cluster via the conserved Cys-93 and Cys-96 when expressed in the E. coli mutant cells in which intracellular free iron content is elevated. Here we report that Fur homologs from Vibrio cholerae and Helicobacter pylori which contain Cys-93 and Cys-96 can also bind a [2Fe-2S] cluster. On the other hand, Fur homolog from Magnetospirillum gryphiswaldense MSR-1 which has no cysteine residues fails to bind any [2Fe-2S] clusters. Interestingly, different Fur proteins with the conserved Cys-93 and Cys-96 have distinct binding activities for the [2Fe-2S] cluster, with H. influenzae Fur having the highest, followed by E. coli Fur, V. cholera Fur, and H. pylori Fur. Binding of the [2Fe-2S] cluster in the Fur proteins is significantly decreased when expressed in wild-type E. coli cells, indicating that binding of the [2Fe-2S] clusters in Fur proteins is regulated by the levels of intracellular free iron content. Finally, unlike the [2Fe-2S] clusters in E. coli ferredoxin, the [2Fe-2S] clusters in the Fur proteins are not stable and quickly release ferrous iron when the clusters are reduced, suggesting that Fur may undergo reversible binding of the [2Fe-2S] cluster in response to intracellular free iron content in bacteria.
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Affiliation(s)
- Chelsey R Fontenot
- Department of Biological Sciences Building, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Huangen Ding
- Department of Biological Sciences Building, Louisiana State University, Baton Rouge, LA, 70803, USA.
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22
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van Dijk MC, de Kruijff RM, Hagedoorn PL. The Role of Iron in Staphylococcus aureus Infection and Human Disease: A Metal Tug of War at the Host—Microbe Interface. Front Cell Dev Biol 2022; 10:857237. [PMID: 35399529 PMCID: PMC8986978 DOI: 10.3389/fcell.2022.857237] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 02/24/2022] [Indexed: 11/27/2022] Open
Abstract
Iron deficiency anemia can be treated with oral or intravenous Fe supplementation. Such supplementation has considerable effects on the human microbiome, and on opportunistic pathogenic micro-organisms. Molecular understanding of the control and regulation of Fe availability at the host-microbe interface is crucial to interpreting the side effects of Fe supplementation. Here, we provide a concise overview of the regulation of Fe by the opportunistic pathogen Staphylococcus aureus. Ferric uptake regulator (Fur) plays a central role in controlling Fe uptake, utilization and storage in order to maintain a required value. The micro-organism has a strong preference for heme iron as an Fe source, which is enabled by the Iron-regulated surface determinant (Isd) system. The strategies it employs to overcome Fe restriction imposed by the host include: hijacking host proteins, replacing metal cofactors, and replacing functions by non-metal dependent enzymes. We propose that integrated omics approaches, which include metalloproteomics, are necessary to provide a comprehensive understanding of the metal tug of war at the host-microbe interface down to the molecular level.
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Affiliation(s)
- Madeleine C. van Dijk
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
- Department of Radiation Science and Technology, Delft University of Technology, Delft, Netherlands
| | - Robin M. de Kruijff
- Department of Radiation Science and Technology, Delft University of Technology, Delft, Netherlands
- *Correspondence: Robin M. de Kruijff, ; Peter-Leon Hagedoorn,
| | - Peter-Leon Hagedoorn
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
- *Correspondence: Robin M. de Kruijff, ; Peter-Leon Hagedoorn,
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23
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Perea-García A, Puig S, Peñarrubia L. The role of post-transcriptional modulators of metalloproteins in response to metal deficiencies. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:1735-1750. [PMID: 34849747 DOI: 10.1093/jxb/erab521] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 11/25/2021] [Indexed: 06/13/2023]
Abstract
Copper and iron proteins have a wide range of functions in living organisms. Metal assembly into metalloproteins is a complex process, where mismetalation is detrimental and energy consuming to cells. Under metal deficiency, metal distribution is expected to reach a metalation ranking, prioritizing essential versus dispensable metalloproteins, while avoiding interference with other metals and protecting metal-sensitive processes. In this review, we propose that post-transcriptional modulators of metalloprotein mRNA (ModMeR) are good candidates in metal prioritization under metal-limited conditions. ModMeR target high quota or redundant metalloproteins and, by adjusting their synthesis, ModMeR act as internal metal distribution valves. Inappropriate metalation of ModMeR targets could compete with metal delivery to essential metalloproteins and interfere with metal-sensitive processes, such as chloroplastic photosynthesis and mitochondrial respiration. Regulation of ModMeR targets could increase or decrease the metal flow through interconnected pathways in cellular metal distribution, helping to achieve adequate differential metal requirements. Here, we describe and compare ModMeR that function in response to copper and iron deficiencies. Specifically, we describe copper-miRNAs from Arabidopsis thaliana and diverse iron ModMeR from yeast, mammals, and bacteria under copper and iron deficiencies, as well as the influence of oxidative stress. Putative functions derived from their role as ModMeR are also discussed.
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Affiliation(s)
- Ana Perea-García
- Departament de Bioquímica i Biologia Molecular and Institut Universitari de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, Burjassot, Valencia, Spain
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | - Sergi Puig
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | - Lola Peñarrubia
- Departament de Bioquímica i Biologia Molecular and Institut Universitari de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, Burjassot, Valencia, Spain
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24
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Liu L, Wang W, Wu S, Gao H. Recent Advances in the Siderophore Biology of Shewanella. Front Microbiol 2022; 13:823758. [PMID: 35250939 PMCID: PMC8891985 DOI: 10.3389/fmicb.2022.823758] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 01/12/2022] [Indexed: 11/17/2022] Open
Abstract
Despite the abundance of iron in nature, iron acquisition is a challenge for life in general because the element mostly exists in the extremely insoluble ferric (Fe3+) form in oxic environments. To overcome this, microbes have evolved multiple iron uptake strategies, a common one of which is through the secretion of siderophores, which are iron-chelating metabolites generated endogenously. Siderophore-mediated iron transport, a standby when default iron transport routes are abolished under iron rich conditions, is essential under iron starvation conditions. While there has been a wealth of knowledge about the molecular basis of siderophore synthesis, uptake and regulation in model bacteria, we still know surprisingly little about siderophore biology in diverse environmental microbes. Shewanella represent a group of γ-proteobacteria capable of respiring a variety of organic and inorganic substrates, including iron ores. This respiratory process relies on a large number of iron proteins, c-type cytochromes in particular. Thus, iron plays an essential and special role in physiology of Shewanella. In addition, these bacteria use a single siderophore biosynthetic system to produce an array of macrocyclic dihydroxamate siderophores, some of which show particular biological activities. In this review, we first outline current understanding of siderophore synthesis, uptake and regulation in model bacteria, and subsequently discuss the siderophore biology in Shewanella.
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Affiliation(s)
- Lulu Liu
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Wei Wang
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Shihua Wu
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Haichun Gao
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, China
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25
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The Yersinia High-Pathogenicity Island Encodes a Siderophore-Dependent Copper Response System in Uropathogenic Escherichia coli. mBio 2022; 13:e0239121. [PMID: 35089085 PMCID: PMC8725597 DOI: 10.1128/mbio.02391-21] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Siderophores are iron chelators used by microbes to bind and acquire iron, which, once in the cell, inhibits siderophore production through feedback repression mediated by the ferric uptake repressor (Fur). Yersiniabactin (Ybt), a siderophore associated with enhanced pathogenic potential among Enterobacteriaceae, also binds copper ions during human and experimental murine infections. In contrast to iron, we found that extracellular copper ions rapidly and selectively stimulate Ybt production in extraintestinal pathogenic Escherichia coli. The stimulatory pathway requires formation of an extracellular copper-Ybt (Cu(II)-Ybt) complex, internalization of Cu(II)-Ybt entry through the canonical TonB-dependent outer membrane transporter, and Fur-independent transcriptional regulation by the specialized transcription factor YbtA. Dual regulation by iron and copper is consistent with a multifunctional metallophore role for Ybt. Feed-forward regulation is typical of stress responses, implicating Ybt in prevention of, or response to, copper stress during infection pathogenesis. IMPORTANCE Interactions between bacteria and transition metal ions play an important role in encounters between humans and bacteria. Siderophore systems have long been prominent mediators of these interactions. These systems secrete small-molecule chelators that bind oxidized iron(III) and express proteins that specifically recognize and import these complexes as a nutritional iron source. While E. coli and other Enterobacteriaceae secrete enterobactin, clinical isolates often secrete an additional siderophore, yersiniabactin (Ybt), which has been found to also bind copper and other non-iron metal ions. The observation here that an extraintestinal E. coli isolate secretes Ybt in a copper-inducible manner suggests an important gain of function over the enterobactin system. Copper recognition involves using Ybt to bind Cu(II) ions, consistent with a distinctively extracellular mode of copper detection. The resulting Cu(II)-Ybt complex signals upregulation of Ybt biosynthesis genes as a rapid response against potentially toxic extracellular copper ions. The Ybt system is distinguishable from other copper response systems that sense cytosolic and periplasmic copper ions. The Ybt dependence of the copper response presents an implicit feed-forward regulatory scheme that is typical of bacterial stress responses. The distinctive extracellular copper recognition-response functionality of the Ybt system may enhance the pathogenic potential of infection-associated Enterobacteriaceae.
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26
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Braun V, Hartmann MD, Hantke K. Transcription regulation of iron carrier transport genes by ECF sigma factors through signaling from the cell surface into the cytoplasm. FEMS Microbiol Rev 2022; 46:6524835. [PMID: 35138377 PMCID: PMC9249621 DOI: 10.1093/femsre/fuac010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 01/26/2022] [Accepted: 02/07/2022] [Indexed: 12/02/2022] Open
Abstract
Bacteria are usually iron-deficient because the Fe3+ in their environment is insoluble or is incorporated into proteins. To overcome their natural iron limitation, bacteria have developed sophisticated iron transport and regulation systems. In gram-negative bacteria, these include iron carriers, such as citrate, siderophores, and heme, which when loaded with Fe3+ adsorb with high specificity and affinity to outer membrane proteins. Binding of the iron carriers to the cell surface elicits a signal that initiates transcription of iron carrier transport and synthesis genes, referred to as “cell surface signaling”. Transcriptional regulation is not coupled to transport. Outer membrane proteins with signaling functions contain an additional N-terminal domain that in the periplasm makes contact with an anti-sigma factor regulatory protein that extends from the outer membrane into the cytoplasm. Binding of the iron carriers to the outer membrane receptors elicits proteolysis of the anti-sigma factor by two different proteases, Prc in the periplasm, and RseP in the cytoplasmic membrane, inactivates the anti-sigma function or results in the generation of an N-terminal peptide of ∼50 residues with pro-sigma activity yielding an active extracytoplasmic function (ECF) sigma factor. Signal recognition and signal transmission into the cytoplasm is discussed herein.
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Affiliation(s)
- Volkmar Braun
- Max Planck Institute for Biology, Department of Protein Evolution, Max Planck Ring 5, 72076 Tübingen, Germany
| | - Marcus D Hartmann
- Max Planck Institute for Biology, Department of Protein Evolution, Max Planck Ring 5, 72076 Tübingen, Germany
| | - Klaus Hantke
- IMIT Institute, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
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27
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Butt AT, Banyard CD, Haldipurkar SS, Agnoli K, Mohsin M, Vitovski S, Paleja A, Tang Y, Lomax R, Ye F, Green J, Thomas M. OUP accepted manuscript. Nucleic Acids Res 2022; 50:3709-3726. [PMID: 35234897 PMCID: PMC9023288 DOI: 10.1093/nar/gkac137] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 01/28/2022] [Accepted: 02/14/2022] [Indexed: 11/14/2022] Open
Abstract
Burkholderia cenocepacia is an opportunistic pathogen that causes severe infections of the cystic fibrosis (CF) lung. To acquire iron, B. cenocepacia secretes the Fe(III)-binding compound, ornibactin. Genes for synthesis and utilisation of ornibactin are served by the iron starvation (IS) extracytoplasmic function (ECF) σ factor, OrbS. Transcription of orbS is regulated in response to the prevailing iron concentration by the ferric uptake regulator (Fur), such that orbS expression is repressed under iron-sufficient conditions. Here we show that, in addition to Fur-mediated regulation of orbS, the OrbS protein itself responds to intracellular iron availability. Substitution of cysteine residues in the C-terminal region of OrbS diminished the ability to respond to Fe(II) in vivo. Accordingly, whilst Fe(II) impaired transcription from and recognition of OrbS-dependent promoters in vitro by inhibiting the binding of OrbS to core RNA polymerase (RNAP), the cysteine-substituted OrbS variant was less responsive to Fe(II). Thus, the cysteine residues within the C-terminal region of OrbS contribute to an iron-sensing motif that serves as an on-board ‘anti-σ factor’ in the presence of Fe(II). A model to account for the presence two regulators (Fur and OrbS) that respond to the same intracellular Fe(II) signal to control ornibactin synthesis and utilisation is discussed.
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Affiliation(s)
- Aaron T Butt
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield S10 2RX, UK
| | - Christopher D Banyard
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield S10 2RX, UK
| | - Sayali S Haldipurkar
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield S10 2RX, UK
| | - Kirsty Agnoli
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield S10 2RX, UK
| | - Muslim I Mohsin
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield S10 2RX, UK
| | - Srdjan Vitovski
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield S10 2RX, UK
| | - Ameya Paleja
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield S10 2RX, UK
| | - Yingzhi Tang
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield S10 2RX, UK
| | - Rebecca Lomax
- Department of Infection, Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield S10 2RX, UK
| | - Fuzhou Ye
- Section of Structural Biology, Department of Infectious Disease, Imperial College London, Sir Alexander Fleming Building, South Kensington, London SW7 2AZ, UK
| | - Jeffrey Green
- Correspondence may also be addressed to Jeffrey Green. Tel: +44 114 222 4403; Fax: +44 114 222 2800;
| | - Mark S Thomas
- To whom correspondence should be addressed. Tel: +44 114 215 9557; Fax: +44 114 271 1863;
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28
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Abstract
Iron is an essential element for Escherichia, Salmonella, and Shigella species. The acquisition of sufficient amounts of iron is difficult in many environments, including the intestinal tract, where these bacteria usually reside. Members of these genera have multiple iron transport systems to transport both ferrous and ferric iron. These include transporters for free ferrous iron, ferric iron associated with chelators, and heme. The numbers and types of transport systems in any species reflect the diversity of niches that it can inhabit. Many of the iron transport genes are found on mobile genetic elements or pathogenicity islands, and there is evidence of the spread of the genes among different species and pathotypes. This is notable among the pathogenic members of the genera in which iron transport systems acquired by horizontal gene transfer allow the bacteria to overcome host innate defenses that act to restrict the availability of iron to the pathogen. The need for iron is balanced by the need to avoid iron overload since excess iron is toxic to the cell. Genes for iron transport and metabolism are tightly regulated and respond to environmental cues, including iron availability, oxygen, and temperature. Master regulators, the iron sensor Fur and the Fur-regulated small RNA (sRNA) RyhB, coordinate the expression of iron transport and cellular metabolism genes in response to the availability of iron.
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29
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Abstract
Building iron-sulfur (Fe-S) clusters and assembling Fe-S proteins are essential actions for life on Earth. The three processes that sustain life, photosynthesis, nitrogen fixation, and respiration, require Fe-S proteins. Genes coding for Fe-S proteins can be found in nearly every sequenced genome. Fe-S proteins have a wide variety of functions, and therefore, defective assembly of Fe-S proteins results in cell death or global metabolic defects. Compared to alternative essential cellular processes, there is less known about Fe-S cluster synthesis and Fe-S protein maturation. Moreover, new factors involved in Fe-S protein assembly continue to be discovered. These facts highlight the growing need to develop a deeper biological understanding of Fe-S cluster synthesis, holo-protein maturation, and Fe-S cluster repair. Here, we outline bacterial strategies used to assemble Fe-S proteins and the genetic regulation of these processes. We focus on recent and relevant findings and discuss future directions, including the proposal of using Fe-S protein assembly as an antipathogen target.
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30
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Liu H, Cao CY, Qiu FL, Huang HN, Xie H, Dong R, Shi YZ, Hu XN. Iron-Rich Conditions Induce OmpA and Virulence Changes of Acinetobacter baumannii. Front Microbiol 2021; 12:725194. [PMID: 34675899 PMCID: PMC8525545 DOI: 10.3389/fmicb.2021.725194] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 08/19/2021] [Indexed: 11/24/2022] Open
Abstract
Background: Iron ions affect the expression of outer membrane protein A (OmpA), a major pathogenic protein in Acinetobacter baumannii. Objective: To analyze the effect of iron ions on the expression of the OmpA protein of A. baumannii and explore its association with the virulence of OmpA. Methods: Site-directed mutagenesis was used to construct ompA gene deletion strains and gene repair strains. The OmpA protein expression of A. baumannii under culture with different contents of iron ions was detected. The virulence of A. baumannii with different OmpA protein expression levels were evaluated in macrophages and mice. Results: OmpA protein levels of the three strains were enhanced under iron-rich conditions. They were reduced in the presence of the iron-chelating agent 2,2′-bipyridine. A. baumannii wild type and + ompA had a remarkable toxic effect on RAW246.7 macrophages (P < 0.05). In contrast, the ΔompA had a significantly reduced toxic effect on RAW246.7 macrophages (P < 0.05). The levels of the inflammatory factors IL-1β, IL-6, IL-8, and TNFα in the mice spleen were significantly increased in the + ompA strain treatment group compared with the ΔompA strain group (all P < 0.05). In addition, the levels were higher in the presence of iron ions than in the presence of the chelating agent. Conclusion: Iron-rich conditions increase the OmpA protein expression of A. baumannii. Strains with high OmpA protein expression were more invasive, which may be a key determinant of A. baumannii infection and pathogenicity. Iron control strategies might be used for the management of A. baumannii.
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Affiliation(s)
- Hui Liu
- Department of Clinical Laboratory, Fujian Longyan First Hospital/Longyan First Affiliated Hospital of Fujian Medical University, Longyan, China
| | - Chun Yuan Cao
- Department of Clinical Laboratory, Fujian Longyan Center for Disease Control and Prevention, Longyan, China
| | - Fu Lan Qiu
- Department of Clinical Laboratory, Fujian Longyan First Hospital/Longyan First Affiliated Hospital of Fujian Medical University, Longyan, China
| | - Hao Nan Huang
- Department of Clinical Laboratory, Fujian Longyan First Hospital/Longyan First Affiliated Hospital of Fujian Medical University, Longyan, China
| | - Hongyan Xie
- Department of Clinical Laboratory, Fujian Longyan First Hospital/Longyan First Affiliated Hospital of Fujian Medical University, Longyan, China
| | - Renkang Dong
- Department of Clinical Laboratory, Fujian Longyan First Hospital/Longyan First Affiliated Hospital of Fujian Medical University, Longyan, China
| | - Yu Zhen Shi
- Intensive Care Unit, Fujian Longyan First Hospital/Longyan First Affiliated Hospital of Fujian Medical University, Longyan, China
| | - Xiu Nian Hu
- Orthopaedic Surgery, Fujian Longyan First Hospital/Longyan First Affiliated Hospital of Fujian Medical University, Longyan, China
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31
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Casanova-Hampton K, Carey A, Kassam S, Garner A, Donati GL, Thangamani S, Subashchandrabose S. A genome-wide screen reveals the involvement of enterobactin-mediated iron acquisition in Escherichia coli survival during copper stress. Metallomics 2021; 13:6355450. [PMID: 34415046 PMCID: PMC8419524 DOI: 10.1093/mtomcs/mfab052] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 08/16/2021] [Indexed: 11/24/2022]
Abstract
Copper (Cu) is a key transition metal that is involved in many important biological processes in a cell. Cu is also utilized by the immune system to hamper pathogen growth during infection. However, genome-level knowledge on the mechanisms involved in adaptation to Cu stress is limited. Here, we report the results of a genome-wide reverse genetic screen for Cu-responsive phenotypes in Escherichia coli. Our screen has identified novel genes involved in adaptation to Cu stress in E. coli. We detected multiple genes involved in the biosynthesis and uptake of enterobactin, a siderophore utilized for high-affinity TonB-dependent acquisition of iron (Fe), as critical players in survival under Cu intoxication. We demonstrated the specificity of Cu-dependent killing by chelation of Cu and by genetic complementation of tonB. Notably, TonB is involved in protection from Cu in both laboratory and uropathogenic strains of E. coli. Cu stress leads to increased expression of the genes involved in Fe uptake, indicating that Fur regulon is derepressed during exposure to excess Cu. Trace element analyses revealed that Fe homeostasis is dysregulated during Cu stress. Taken together, our data supports a model in which lack of enterobactin-dependent Fe uptake leads to exacerbation of Cu toxicity, and elucidates the intricate connection between the homeostasis of Cu and Fe in a bacterial cell.
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Affiliation(s)
- Kaitlin Casanova-Hampton
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - Alexis Carey
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - Sarah Kassam
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - Alyssa Garner
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - George L Donati
- Department of Chemistry, Wake Forest University, Winston-Salem, NC, USA
| | - Shankar Thangamani
- Department of Pathology and Population Medicine, College of Veterinary Medicine, Midwestern University, Glendale, AZ, USA
| | - Sargurunathan Subashchandrabose
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
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32
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Thioredoxin Dependent Changes in the Redox States of FurA from Anabaena sp. PCC 7120. Antioxidants (Basel) 2021; 10:antiox10060913. [PMID: 34199999 PMCID: PMC8229018 DOI: 10.3390/antiox10060913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 05/31/2021] [Accepted: 06/01/2021] [Indexed: 11/21/2022] Open
Abstract
FurA is a multifunctional regulator in cyanobacteria that contains five cysteines, four of them arranged into two CXXC motifs. Lack of a structural zinc ion enables FurA to develop disulfide reductase activity. In vivo, FurA displays several redox isoforms, and the oxidation state of its cysteines determines its activity as regulator and its ability to bind different metabolites. Because of the relationship between FurA and the control of genes involved in oxidative stress defense and photosynthetic metabolism, we sought to investigate the role of type m thioredoxin TrxA as a potential redox partner mediating dithiol-disulfide exchange reactions necessary to facilitate the interaction of FurA with its different ligands. Both in vitro cross-linking assays and in vivo two-hybrid studies confirmed the interaction between FurA and TrxA. Light to dark transitions resulted in reversible oxidation of a fraction of the regulator present in Anabaena sp. PCC7120. Reconstitution of an electron transport chain using E. coli NADPH-thioredoxin-reductase followed by alkylation of FurA reduced cysteines evidenced the ability of TrxA to reduce FurA. Furthermore, the use of site-directed mutants allowed us to propose a plausible mechanism for FurA reduction. These results point to TrxA as one of the redox partners that modulates FurA performance.
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Ittensohn J, Hemberger J, Griffiths H, Keller M, Albrecht S, Miethke T. Regulation of Expression of the TIR-Containing Protein C Gene of the Uropathogenic Escherichia coli Strain CFT073. Pathogens 2021; 10:pathogens10050549. [PMID: 34062817 PMCID: PMC8147327 DOI: 10.3390/pathogens10050549] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 04/23/2021] [Accepted: 04/27/2021] [Indexed: 11/22/2022] Open
Abstract
The uropathogenic Escherichia coli strain CFT073 causes kidney abscesses in mice Toll/interleukin-1 receptor domain-containing protein C (TcpC) dependently and the corresponding gene is present in around 40% of E. coli isolates of pyelonephritis patients. It impairs the Toll-like receptor (TLR) signaling chain and the NACHT leucin-rich repeat PYD protein 3 inflammasome (NLRP3) by binding to TLR4 and myeloid differentiation factor 88 as well as to NLRP3 and caspase-1, respectively. Overexpression of the tcpC gene stopped replication of CFT073. Overexpression of several tcpC-truncation constructs revealed a transmembrane region, while its TIR domain induced filamentous bacteria. Based on these observations, we hypothesized that tcpC expression is presumably tightly controlled. We tested two putative promoters designated P1 and P2 located at 5′ of the gene c2397 and 5′ of the tcpC gene (c2398), respectively, which may form an operon. High pH and increasing glucose concentrations stimulated a P2 reporter construct that was considerably stronger than a P1 reporter construct, while increasing FeSO4 concentrations suppressed their activity. Human urine activated P2, demonstrating that tcpC might be induced in the urinary tract of infected patients. We conclude that P2, consisting of a 240 bp region 5′ of the tcpC gene, represents the major regulator of tcpC expression.
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Affiliation(s)
- Julia Ittensohn
- Medical Faculty of Mannheim, Institute of Medical Microbiology and Hygiene, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany; (J.I.); (J.H.); (H.G.); (M.K.); (S.A.)
- Medical Faculty of Mannheim, Mannheim Institute for Innate Immunoscience (MI3), University of Heidelberg, Ludolf-Krehl-Str. 13-17, 68167 Mannheim, Germany
| | - Jacqueline Hemberger
- Medical Faculty of Mannheim, Institute of Medical Microbiology and Hygiene, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany; (J.I.); (J.H.); (H.G.); (M.K.); (S.A.)
- Medical Faculty of Mannheim, Mannheim Institute for Innate Immunoscience (MI3), University of Heidelberg, Ludolf-Krehl-Str. 13-17, 68167 Mannheim, Germany
| | - Hannah Griffiths
- Medical Faculty of Mannheim, Institute of Medical Microbiology and Hygiene, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany; (J.I.); (J.H.); (H.G.); (M.K.); (S.A.)
- Medical Faculty of Mannheim, Mannheim Institute for Innate Immunoscience (MI3), University of Heidelberg, Ludolf-Krehl-Str. 13-17, 68167 Mannheim, Germany
| | - Maren Keller
- Medical Faculty of Mannheim, Institute of Medical Microbiology and Hygiene, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany; (J.I.); (J.H.); (H.G.); (M.K.); (S.A.)
- Medical Faculty of Mannheim, Mannheim Institute for Innate Immunoscience (MI3), University of Heidelberg, Ludolf-Krehl-Str. 13-17, 68167 Mannheim, Germany
| | - Simone Albrecht
- Medical Faculty of Mannheim, Institute of Medical Microbiology and Hygiene, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany; (J.I.); (J.H.); (H.G.); (M.K.); (S.A.)
- Medical Faculty of Mannheim, Mannheim Institute for Innate Immunoscience (MI3), University of Heidelberg, Ludolf-Krehl-Str. 13-17, 68167 Mannheim, Germany
| | - Thomas Miethke
- Medical Faculty of Mannheim, Institute of Medical Microbiology and Hygiene, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany; (J.I.); (J.H.); (H.G.); (M.K.); (S.A.)
- Medical Faculty of Mannheim, Mannheim Institute for Innate Immunoscience (MI3), University of Heidelberg, Ludolf-Krehl-Str. 13-17, 68167 Mannheim, Germany
- Correspondence:
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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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Lill R. Do FeS clusters rule bacterial iron regulation? J Biol Chem 2020; 295:15464-15465. [PMID: 33188081 DOI: 10.1074/jbc.h120.016190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
For decades, the bacterial ferric uptake regulator (Fur) has been thought to respond to ferrous iron to transcriptionally regulate genes required for balancing iron uptake, storage, and utilization. Because iron binding to Fur has never been confirmed in vivo, the physiological iron-sensing mechanism remains an open question. Fontenot et al. now show that Fur purified from Escherichia coli binds an all-Cys-coordinated [2Fe-2S] cluster. This finding opens the exciting possibility that Fur may join numerous well-studied bacterial, fungal, and mammalian proteins that use FeS clusters for cellular iron regulation.
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Affiliation(s)
- Roland Lill
- Institut für Zytobiologie, Philipps-Universität Marburg, Marburg, Germany; SYNMIKRO Center for Synthetic Microbiology, Philipps-Universität Marburg, Marburg, Germany.
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