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Stuut Balsam S, Zhong F, Pence N, Levintov L, Andhare D, Hammond JH, Ragusa MJ, Vashisth H, Hogan DA, Pletneva EV. Conserved C-Terminal Tail Is Responsible for Membrane Localization and Function of Pseudomonas aeruginosa Hemerythrin. Biochemistry 2024; 63:1795-1807. [PMID: 38951132 DOI: 10.1021/acs.biochem.4c00174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/03/2024]
Abstract
Many bacteria have hemerythrin (Hr) proteins that bind O2, including Pseudomonas aeruginosa, in which microoxia-induced Hr (Mhr) provide fitness advantages under microoxic conditions. Mhr has a 23 amino-acid extension at its C-terminus relative to a well-characterized Hr from Methylococcus capsulatus, and similar extensions are also found in Hrs from other bacteria. The last 11 amino acids of this extended, C-terminal tail are highly conserved in gammaproteobacteria and predicted to form a helix with positively charged and hydrophobic faces. In cellular fractionation assays, wild-type (WT) Mhr was found in both membrane and cytosolic fractions, while a MhrW143* variant lacking the last 11 residues was largely in the cytosol and did not complement Mhr function in competition assays. MhrL112Y, a variant that has a much longer-lived O2-bound form, was fully functional and had a similar localization pattern to that of WT Mhr. Both MhrW143* and MhrL112Y had secondary structures, stabilities, and O2-binding kinetics similar to those of WT Mhr. Fluorescence studies revealed that the C-terminal tail, and particularly the fragment corresponding to its last 11 residues, was sufficient and necessary for association with lipid vesicles. Molecular dynamics simulations and subsequent cellular analysis of Mhr variants have demonstrated that conserved, positively charged residues in the tail are important for Mhr interactions with negatively charged membranes and the contribution of this protein to competitive fitness. Together, these data suggest that peripheral interactions of Mhr with membranes are guided by the C-terminal tail and are independent of O2-binding.
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Affiliation(s)
- Stacie Stuut Balsam
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, United States
| | - Fangfang Zhong
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Natasha Pence
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Lev Levintov
- Department of Chemical Engineering and Bioengineering, University of New Hampshire, Durham, New Hampshire 03824, United States
| | - Devika Andhare
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - John H Hammond
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, United States
| | - Michael J Ragusa
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Harish Vashisth
- Department of Chemical Engineering and Bioengineering, University of New Hampshire, Durham, New Hampshire 03824, United States
- Department of Chemistry, University of New Hampshire, Durham, New Hampshire 03824, United States
- Integrated Applied Mathematics Program, University of New Hampshire, Durham, New Hampshire 03824, United States
- Molecular and Cellular Biotechnology Program, University of New Hampshire, Durham, New Hampshire 03824, United States
| | - Deborah A Hogan
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, United States
| | - Ekaterina V Pletneva
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
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2
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Hoque NJ, Weinert EE. Control of bacterial second messenger signaling and motility by heme-based direct oxygen-sensing proteins. Curr Opin Microbiol 2023; 76:102396. [PMID: 37864983 DOI: 10.1016/j.mib.2023.102396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/15/2023] [Accepted: 09/21/2023] [Indexed: 10/23/2023]
Abstract
Bacteria sense and respond to their environment, allowing them to maximize their survival and growth under changing conditions, such as oxygen levels. Direct oxygen-sensing proteins allow bacteria to rapidly sense concentration changes and adapt by regulating signaling pathways and/or cellular machinery. Recent work has identified roles for direct oxygen-sensing proteins in controlling second messenger levels and motility machinery, as well as effects on biofilm formation, virulence, and motility. In this review, we discuss recent progress in understanding O2-dependent regulation of cyclic di-GMP signaling and motility and highlight the emerging importance in controlling bacterial physiology and behavior.
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Affiliation(s)
- Nushrat J Hoque
- Department of Chemistry, Penn State University, University Park, PA 16802, USA
| | - Emily E Weinert
- Department of Chemistry, Penn State University, University Park, PA 16802, USA; Department of Biochemistry & Molecular Biology, Penn State University, University Park, PA 16802, USA.
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3
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Yu Z, Zhang W, Yang H, Chou SH, Galperin MY, He J. Gas and light: triggers of c-di-GMP-mediated regulation. FEMS Microbiol Rev 2023; 47:fuad034. [PMID: 37339911 PMCID: PMC10505747 DOI: 10.1093/femsre/fuad034] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 06/01/2023] [Accepted: 06/17/2023] [Indexed: 06/22/2023] Open
Abstract
The widespread bacterial second messenger c-di-GMP is responsible for regulating many important physiological functions such as biofilm formation, motility, cell differentiation, and virulence. The synthesis and degradation of c-di-GMP in bacterial cells depend, respectively, on diguanylate cyclases and c-di-GMP-specific phosphodiesterases. Since c-di-GMP metabolic enzymes (CMEs) are often fused to sensory domains, their activities are likely controlled by environmental signals, thereby altering cellular c-di-GMP levels and regulating bacterial adaptive behaviors. Previous studies on c-di-GMP-mediated regulation mainly focused on downstream signaling pathways, including the identification of CMEs, cellular c-di-GMP receptors, and c-di-GMP-regulated processes. The mechanisms of CME regulation by upstream signaling modules received less attention, resulting in a limited understanding of the c-di-GMP regulatory networks. We review here the diversity of sensory domains related to bacterial CME regulation. We specifically discuss those domains that are capable of sensing gaseous or light signals and the mechanisms they use for regulating cellular c-di-GMP levels. It is hoped that this review would help refine the complete c-di-GMP regulatory networks and improve our understanding of bacterial behaviors in changing environments. In practical terms, this may eventually provide a way to control c-di-GMP-mediated bacterial biofilm formation and pathogenesis in general.
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Affiliation(s)
- Zhaoqing Yu
- National Key Laboratory of Agricultural Microbiology and Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, 1 Shizishan Street, Wuhan, Hubei 430070, PR China
- Institute of Agro-Product Processing, Jiangsu Academy of Agricultural Sciences, 50 Zhongling Street, Nanjing, Jiangsu 210014, PR China
| | - Wei Zhang
- National Key Laboratory of Agricultural Microbiology and Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, 1 Shizishan Street, Wuhan, Hubei 430070, PR China
| | - He Yang
- National Key Laboratory of Agricultural Microbiology and Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, 1 Shizishan Street, Wuhan, Hubei 430070, PR China
| | - Shan-Ho Chou
- National Key Laboratory of Agricultural Microbiology and Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, 1 Shizishan Street, Wuhan, Hubei 430070, PR China
| | - Michael Y Galperin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, 8600 Rockville Pike, Bethesda, MD 20894, USA
| | - Jin He
- National Key Laboratory of Agricultural Microbiology and Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, 1 Shizishan Street, Wuhan, Hubei 430070, PR China
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4
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Ximinies AD, Dou Y, Mishra A, Zhang K, Deivanayagam C, Wang C, Fletcher HM. The Oxidative Stress-Induced Hypothetical Protein PG_0686 in Porphyromonas gingivalis W83 Is a Novel Diguanylate Cyclase. Microbiol Spectr 2023; 11:e0441122. [PMID: 36719196 PMCID: PMC10101095 DOI: 10.1128/spectrum.04411-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 01/06/2023] [Indexed: 02/01/2023] Open
Abstract
The survival/adaptation of Porphyromonas gingivalis to the inflammatory environment of the periodontal pocket requires an ability to overcome oxidative stress. Several functional classes of genes, depending on the severity and duration of the exposure, were induced in P. gingivalis under H2O2-induced oxidative stress. The PG_0686 gene was highly upregulated under prolonged oxidative stress. PG_0686, annotated as a hypothetical protein of unknown function, is a 60 kDa protein that carries several domains including hemerythrin, PAS10, and domain of unknown function (DUF)-1858. Although PG_0686 showed some relatedness to several diguanylate cyclases (DGCs), it is missing the classical conserved, active site sequence motif (GGD[/E]EF), commonly observed in other bacteria. PG_0686-related proteins are observed in other anaerobic bacterial species. The isogenic mutant P. gingivalis FLL361 (ΔPG_0686::ermF) showed increased sensitivity to H2O2, and decreased gingipain activity compared to the parental strain. Transcriptome analysis of P. gingivalis FLL361 showed the dysregulation of several gene clusters/operons, known oxidative stress resistance genes, and transcriptional regulators, including PG_2212, CdhR and PG_1181 that were upregulated under normal anaerobic conditions. The intracellular level of c-di-GMP in P. gingivalis FLL361 was significantly decreased compared to the parental strain. The purified recombinant PG_0686 (rPG_0686) protein catalyzed the formation of c-di-GMP from GTP. Collectively, our data suggest a global regulatory property for PG_0686 that may be part of an unconventional second messenger signaling system in P. gingivalis. Moreover, it may coordinately regulate a pathway(s) vital for protection against environmental stress, and is significant in the pathogenicity of P. gingivalis and other anaerobes. IMPORTANCE Porphyromonas gingivalis is an important etiological agent in periodontitis and other systemic diseases. There is still a gap in our understanding of the mechanisms that P. gingivalis uses to survive the inflammatory microenvironment of the periodontal pocket. The hypothetical PG_0686 gene was highly upregulated under prolonged oxidative stress. Although the tertiary structure of PG_0686 showed little relatedness to previously characterized diguanylate cyclases (DGCs), and does not contain the conserved GGD(/E)EF catalytic domain motif sequence, an ability to catalyze the formation of c-di-GMP from GTP is demonstrated. The second messenger pathway for c-di-GMP was previously predicted to be absent in P. gingivalis. PG_0686 paralogs are identified in other anaerobic bacteria. Thus, PG_0686 may represent a novel class of DGCs, which is yet to be characterized. In conclusion, we have shown, for the first time, evidence for the presence of c-di-GMP signaling with environmental stress protective function in P. gingivalis.
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Affiliation(s)
- Alexia D. Ximinies
- Division of Microbiology & Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, California, USA
| | - Yuetan Dou
- Division of Microbiology & Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, California, USA
| | - Arunima Mishra
- Division of Microbiology & Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, California, USA
| | - Kangling Zhang
- Department of Pharmacology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Champion Deivanayagam
- Department of Biochemistry and Molecular Genetics, University of Alabama, Birmingham, Alabama, USA
| | - Charles Wang
- Division of Microbiology & Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, California, USA
| | - Hansel M. Fletcher
- Division of Microbiology & Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, California, USA
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5
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Kitanishi K. Bacterial hemerythrin domain-containing oxygen and redox sensors: Versatile roles for oxygen and redox signaling. Front Mol Biosci 2022; 9:967059. [PMID: 35992274 PMCID: PMC9388753 DOI: 10.3389/fmolb.2022.967059] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 07/01/2022] [Indexed: 11/13/2022] Open
Abstract
Hemerythrin is an oxygen-binding protein originally found in certain marine invertebrates. Oxygen reversibly binds at its non-heme diiron center, which consists of two oxo-bridged iron atoms bound to a characteristic conserved set of five His residues, one Glu residue, and one Asp residue. It was recently discovered that several bacteria utilize hemerythrin as an oxygen- and redox-sensing domain in responding to changes in cellular oxygen concentration or redox status, and immediately adapt to these environmental changes in order to maintain important physiological processes, including chemotaxis and c-di-GMP synthesis and degradation. This Mini Review focuses on the recent progress made on structural and functional aspects of these emerging bacterial hemerythrin domain-containing oxygen and redox sensors, revealing characteristic features of this family of proteins.
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Nitric oxide stimulates type IV MSHA pilus retraction in Vibrio cholerae via activation of the phosphodiesterase CdpA. Proc Natl Acad Sci U S A 2022; 119:2108349119. [PMID: 35135874 PMCID: PMC8851539 DOI: 10.1073/pnas.2108349119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2021] [Indexed: 01/30/2023] Open
Abstract
All organisms sense and respond to their environments. One way bacteria interact with their surroundings is by dynamically extending and retracting filamentous appendages from their surface called pili. While pili are critical for many functions, such as attachment, motility, and DNA uptake, the factors that regulate their dynamic activity are poorly understood. Here, we describe how an environmental signal induces a signaling pathway to promote the retraction of mannose-sensitive hemagglutinin pili in Vibrio cholerae. The retraction of these pili promotes the detachment of V. cholerae from a surface and may provide a means by which V. cholerae can respond to changes in its environment. Bacteria use surface appendages called type IV pili to perform diverse activities including DNA uptake, twitching motility, and attachment to surfaces. The dynamic extension and retraction of pili are often required for these activities, but the stimuli that regulate these dynamics remain poorly characterized. To address this question, we study the bacterial pathogen Vibrio cholerae, which uses mannose-sensitive hemagglutinin (MSHA) pili to attach to surfaces in aquatic environments as the first step in biofilm formation. Here, we use a combination of genetic and cell biological approaches to describe a regulatory pathway that allows V. cholerae to rapidly abort biofilm formation. Specifically, we show that V. cholerae cells retract MSHA pili and detach from a surface in a diffusion-limited, enclosed environment. This response is dependent on the phosphodiesterase CdpA, which decreases intracellular levels of cyclic-di-GMP to induce MSHA pilus retraction. CdpA contains a putative nitric oxide (NO)–sensing NosP domain, and we demonstrate that NO is necessary and sufficient to stimulate CdpA-dependent detachment. Thus, we hypothesize that the endogenous production of NO (or an NO-like molecule) in V. cholerae stimulates the retraction of MSHA pili. These results extend our understanding of how environmental cues can be integrated into the complex regulatory pathways that control pilus dynamic activity and attachment in bacterial species.
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Calcium-Responsive Diguanylate Cyclase CasA Drives Cellulose-Dependent Biofilm Formation and Inhibits Motility in Vibrio fischeri. mBio 2021; 12:e0257321. [PMID: 34749532 PMCID: PMC8576532 DOI: 10.1128/mbio.02573-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The marine bacterium Vibrio fischeri colonizes its host, the Hawaiian bobtail squid, in a manner requiring both bacterial biofilm formation and motility. The decision to switch between sessile and motile states is often triggered by environmental signals and regulated by the widespread signaling molecule c-di-GMP. Calcium is an environmental signal previously shown to affect both biofilm formation and motility by V. fischeri. In this study, we investigated the link between calcium and c-di-GMP, determining that calcium increases intracellular c-di-GMP dependent on a specific diguanylate cyclase, calcium-sensing protein A (CasA). CasA is activated by calcium, dependent on residues in an N-terminal sensory domain, and synthesizes c-di-GMP through an enzymatic C-terminal domain. CasA is responsible for calcium-dependent inhibition of motility and activation of cellulose-dependent biofilm formation. Calcium regulates cellulose biofilms at the level of transcription, which also requires the transcription factor VpsR. Finally, the Vibrio cholerae CasA homolog, CdgK, is unable to complement CasA and may be inhibited by calcium. Collectively, these results identify CasA as a calcium-responsive regulator, linking an external signal to internal decisions governing behavior, and shed light on divergence between Vibrio spp.
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8
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Abstract
Cyclic diguanylate (c-di-GMP) signal transduction systems provide bacteria with the ability to sense changing cell status or environmental conditions and then execute suitable physiological and social behaviors in response. In this review, we provide a comprehensive census of the stimuli and receptors that are linked to the modulation of intracellular c-di-GMP. Emerging evidence indicates that c-di-GMP networks sense light, surfaces, energy, redox potential, respiratory electron acceptors, temperature, and structurally diverse biotic and abiotic chemicals. Bioinformatic analysis of sensory domains in diguanylate cyclases and c-di-GMP-specific phosphodiesterases as well as the receptor complexes associated with them reveals that these functions are linked to a diverse repertoire of protein domain families. We describe the principles of stimulus perception learned from studying these modular sensory devices, illustrate how they are assembled in varied combinations with output domains, and summarize a system for classifying these sensor proteins based on their complexity. Biological information processing via c-di-GMP signal transduction not only is fundamental to bacterial survival in dynamic environments but also is being used to engineer gene expression circuitry and synthetic proteins with à la carte biochemical functionalities.
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Gonzaga de França Lopes L, Gouveia Júnior FS, Karine Medeiros Holanda A, Maria Moreira de Carvalho I, Longhinotti E, Paulo TF, Abreu DS, Bernhardt PV, Gilles-Gonzalez MA, Cirino Nogueira Diógenes I, Henrique Silva Sousa E. Bioinorganic systems responsive to the diatomic gases O2, NO, and CO: From biological sensors to therapy. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.214096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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10
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Dippel AB, Anderson WA, Park JH, Yildiz FH, Hammond MC. Development of Ratiometric Bioluminescent Sensors for in Vivo Detection of Bacterial Signaling. ACS Chem Biol 2020; 15:904-914. [PMID: 32186367 DOI: 10.1021/acschembio.9b00800] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Second messenger signaling networks allow cells to sense and adapt to changing environmental conditions. In bacteria, the nearly ubiquitous second messenger molecule cyclic di-GMP coordinates diverse processes such as motility, biofilm formation, and virulence. In bacterial pathogens, these signaling networks allow the bacteria to survive changing environmental conditions that are experienced during infection of a mammalian host. While studies have examined the effects of cyclic di-GMP levels on virulence in these pathogens, it has not been possible to visualize cyclic di-GMP levels in real time during the stages of host infection. Toward this goal, we generate the first ratiometric, chemiluminescent biosensor scaffold that selectively responds to c-di-GMP. By engineering the biosensor scaffold, a suite of Venus-YcgR-NLuc (VYN) biosensors is generated that provide extremely high sensitivity (KD < 300 pM) and large changes in the bioluminescence resonance energy transfer (BRET) signal (up to 109%). As a proof-of-concept that VYN biosensors can image cyclic di-GMP in tissues, we show that the VYN biosensors function in the context of a tissue phantom model, with only ∼103-104 biosensor-expressing E. coli cells required for the measurement. Furthermore, we utilize the biosensor in vitro to assess changes in cyclic di-GMP in V. cholerae grown with different inputs found in the host environment. The VYN sensors developed here can serve as robust in vitro diagnostic tools for high throughput screening, as well as genetically encodable tools for monitoring the dynamics of c-di-GMP in live cells, and lay the groundwork for live cell imaging of c-di-GMP dynamics in bacteria within tissues and other complex environments.
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Affiliation(s)
- Andrew B. Dippel
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
- Department of Chemistry and Henry Eyring Center for Cell and Genome Sciences, University of Utah, Salt Lake City, Utah 84112, United States
| | - Wyatt A. Anderson
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
- Department of Chemistry and Henry Eyring Center for Cell and Genome Sciences, University of Utah, Salt Lake City, Utah 84112, United States
| | - Jin Hwan Park
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, California 95064, United States
| | - Fitnat H. Yildiz
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, California 95064, United States
| | - Ming C. Hammond
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
- Department of Chemistry and Henry Eyring Center for Cell and Genome Sciences, University of Utah, Salt Lake City, Utah 84112, United States
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Kitanishi K, Igarashi J, Matsuoka A, Unno M. Identification and Characterization of a Redox Sensor Phosphodiesterase from Ferrovum sp. PN-J185 Containing Bacterial Hemerythrin and HD-GYP Domains. Biochemistry 2020; 59:983-991. [PMID: 32045213 DOI: 10.1021/acs.biochem.0c00021] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The second messenger bis(3',5')-cyclic dimeric guanosine monophosphate (c-di-GMP) regulates numerous important physiological functions in bacteria. In this study, we identified and characterized the first dimeric, full-length, non-heme iron-bound phosphodiesterase (PDE) containing bacterial hemerythrin and HD-GYP domains (Bhr-HD-GYP). We found that the amino acid sequence encoded by the FV185_09380 gene from Ferrovum sp. PN-J185 contains an N-terminal bacterial hemerythrin domain and a C-terminal HD-GYP domain, which is characteristic of proteins with PDE activity toward c-di-GMP. Inductively coupled plasma optical emission spectroscopy analyses showed that Bhr-HD-GYP contains 4 equiv of iron atoms per subunit, suggesting both hemerythrin and HD-GYP domains have non-heme di-iron sites. A redox-dependent spectral change expected for oxo-bridged non-heme iron with carboxylate ligands was observed, and this redox interconversion was reversible. However, unlike marine invertebrate hemerythrin, which functions as an oxygen-binding protein, Bhr-HD-GYP did not form an oxygen adduct because of rapid autoxidation. The reduced ferrous iron complex of the protein catalyzed the hydrolysis of c-di-GMP to its linearized product, 5'-phosphoguanylyl-(3',5')-guanosine (pGpG), whereas the oxidized ferric iron complex had no significant activity. These results suggest that Bhr-HD-GYP is a redox and oxygen sensor enzyme that regulates c-di-GMP levels in response to changes in cellular redox status or oxygen concentration. Our study may lead to an improved understanding of the physiology of iron-oxidizing bacterium Ferrovum sp. PN-J185.
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Affiliation(s)
- Kenichi Kitanishi
- Department of Chemistry, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan.,Graduate School of Science and Engineering, Ibaraki University, 4-12-1 Nakanarusawa, Hitachi, Ibaraki 316-8511, Japan.,Frontier Research Center for Applied Atomic Sciences, Ibaraki University, 162-1 Shirakata, Tokai, Naka, Ibaraki 319-1106, Japan
| | - Jotaro Igarashi
- Department of Natural Sciences, Fukushima Medical University, 1 Hikariga-oka, Fukushima 960-1295, Japan
| | - Ariki Matsuoka
- Department of Natural Sciences, Fukushima Medical University, 1 Hikariga-oka, Fukushima 960-1295, Japan
| | - Masaki Unno
- Graduate School of Science and Engineering, Ibaraki University, 4-12-1 Nakanarusawa, Hitachi, Ibaraki 316-8511, Japan.,Frontier Research Center for Applied Atomic Sciences, Ibaraki University, 162-1 Shirakata, Tokai, Naka, Ibaraki 319-1106, Japan
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12
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Benavides BS, Valandro S, Kurtz DM. Preparation of platinum nanoparticles using iron( ii) as reductant and photosensitized H 2 generation on an iron storage protein scaffold. RSC Adv 2020; 10:5551-5559. [PMID: 35497424 PMCID: PMC9049210 DOI: 10.1039/d0ra00341g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 01/27/2020] [Indexed: 12/31/2022] Open
Abstract
The quest for efficient solar-to-fuel conversion has led to the development of numerous homogeneous and heterogeneous systems for photochemical stimulation of 2H+ + 2e− → H2. Many such systems consist of a photosensitizer, an H2-evolving catalyst (HEC), and sacrificial electron donor often with an electron relay between photosensitizer and HEC. Colloidal platinum remains a popular HEC. We report here a novel, simple, and high yield synthesis of Pt nanoparticles (Pt NPs) associated with human heavy chain ferritin (Hfn). The formation of the Pt NPs capitalizes on Hfn's native catalysis of autoxidation of Fe(ii)(aq) (ferroxidase activity). Fe(ii) reduces Pt(ii) to Pt(0) and the rapid ferroxidase reaction produces FeO(OH), which associates with and stabilizes the incipient Pt NPs. This Pt/Fe-Hfn efficiently catalyzes photosensitized H2 production when combined with Eosin Y (EY) as photosensitizer and triethanolamine (TEOA) as sacrificial electron donor. With white light irradiation turnover numbers of 300H2 per Pt, 250H2 per EY were achieved. A quantum yield of 18% for H2 production was obtained with 550 nm irradiation. The fluorescence emission of EY is quenched by TEOA but not by Pt/Fe-Hfn. We propose that the photosensitized H2 production from aqueous TEOA, EY, Pt/Fe-Hfn solution occurs via a reductive quenching pathway in which both the singlet and triplet excited states of EY are reduced by TEOA to the anion radical, EY−˙, which in turn transfers electrons to the Pt/Fe-Hfn HEC. Hfn is known to be a remarkably versatile scaffold for incorporation and stabilization of noble metal and semiconductor nanoparticles. Since both EY and Hfn are amenable to scale-up, we envision further refinements to and applications of this photosensitized H2-generating system. An assembly of platinum nanoparticles produced by Fe(ii) reduction of Pt(ii) and stabilized by human heavy chain ferritin's native catalysis of Fe(ii)(aq) autoxidation functions as an efficient photosensitized H2 evolution catalyst.![]()
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Affiliation(s)
| | - Silvano Valandro
- Department of Chemistry
- University of Texas at San Antonio
- San Antonio
- USA
| | - Donald M. Kurtz
- Department of Chemistry
- University of Texas at San Antonio
- San Antonio
- USA
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13
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Smith GJ, Angle JC, Solden LM, Borton MA, Morin TH, Daly RA, Johnston MD, Stefanik KC, Wolfe R, Gil B, Wrighton KC. Members of the Genus Methylobacter Are Inferred To Account for the Majority of Aerobic Methane Oxidation in Oxic Soils from a Freshwater Wetland. mBio 2018; 9:e00815-18. [PMID: 30401770 PMCID: PMC6222125 DOI: 10.1128/mbio.00815-18] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 10/01/2018] [Indexed: 11/20/2022] Open
Abstract
Microbial carbon degradation and methanogenesis in wetland soils generate a large proportion of atmospheric methane, a highly potent greenhouse gas. Despite their potential to mitigate greenhouse gas emissions, knowledge about methane-consuming methanotrophs is often limited to lower-resolution single-gene surveys that fail to capture the taxonomic and metabolic diversity of these microorganisms in soils. Here our objective was to use genome-enabled approaches to investigate methanotroph membership, distribution, and in situ activity across spatial and seasonal gradients in a freshwater wetland near Lake Erie. 16S rRNA gene analyses demonstrated that members of the methanotrophic Methylococcales were dominant, with the dominance largely driven by the relative abundance of four taxa, and enriched in oxic surface soils. Three methanotroph genomes from assembled soil metagenomes were assigned to the genus Methylobacter and represented the most abundant methanotrophs across the wetland. Paired metatranscriptomes confirmed that these Old Woman Creek (OWC) Methylobacter members accounted for nearly all the aerobic methanotrophic activity across two seasons. In addition to having the capacity to couple methane oxidation to aerobic respiration, these new genomes encoded denitrification potential that may sustain energy generation in soils with lower dissolved oxygen concentrations. We further show that Methylobacter members that were closely related to the OWC members were present in many other high-methane-emitting freshwater and soil sites, suggesting that this lineage could participate in methane consumption in analogous ecosystems. This work contributes to the growing body of research suggesting that Methylobacter may represent critical mediators of methane fluxes in freshwater saturated sediments and soils worldwide.IMPORTANCE Here we used soil metagenomics and metatranscriptomics to uncover novel members within the genus Methylobacter We denote these closely related genomes as members of the lineage OWC Methylobacter Despite the incredibly high microbial diversity in soils, here we present findings that unexpectedly showed that methane cycling was primarily mediated by a single genus for both methane production ("Candidatus Methanothrix paradoxum") and methane consumption (OWC Methylobacter). Metatranscriptomic analyses revealed that decreased methanotrophic activity rather than increased methanogenic activity possibly contributed to the greater methane emissions that we had previously observed in summer months, findings important for biogeochemical methane models. Although members of this Methylococcales order have been cultivated for decades, multi-omic approaches continue to illuminate the methanotroph phylogenetic and metabolic diversity harbored in terrestrial and marine ecosystems.
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Affiliation(s)
- Garrett J Smith
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | - Jordan C Angle
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | - Lindsey M Solden
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | - Mikayla A Borton
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, Colorado, USA
- Environmental Science Graduate Program, The Ohio State University, Columbus, Ohio, USA
| | - Timothy H Morin
- Department of Environmental Resources Engineering, State University of New York College of Environmental Science and Forestry, Syracuse, New York, USA
| | - Rebecca A Daly
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Michael D Johnston
- National Institute of Environmental Health Sciences, Durham, North Carolina, USA
| | - Kay C Stefanik
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
- Department of Civil and Environmental Engineering and Geodetic Sciences, The Ohio State University, Columbus, Ohio, USA
| | - Richard Wolfe
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Bohrer Gil
- Environmental Science Graduate Program, The Ohio State University, Columbus, Ohio, USA
- Department of Civil and Environmental Engineering and Geodetic Sciences, The Ohio State University, Columbus, Ohio, USA
| | - Kelly C Wrighton
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, Colorado, USA
- Environmental Science Graduate Program, The Ohio State University, Columbus, Ohio, USA
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14
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Stoian SA, Peng YR, Beedle CC, Chung YJ, Lee GH, Yang EC, Hill S. Structural, Spectroscopic, and Theoretical Investigation of a T-Shaped [Fe 3(μ 3-O)] Cluster. Inorg Chem 2017; 56:10861-10874. [PMID: 28845975 DOI: 10.1021/acs.inorgchem.7b00455] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The synthesis, X-ray crystal and electronic structures of [Fe3(μ3-O)(mpmae)2(OAc)2 Cl3], 1, where mpmae-H = 2-(N-methyl-N-((pyridine-2-yl)methyl)amino)ethanol, are described. This cluster comprises three high-spin ferric ions and exhibits a T-shaped site topology. Variable-frequency electron paramagnetic resonance measurements performed on single crystals of 1 demonstrate a total spin ST = 5/2 ground state, characterized by a small, negative, and nearly axial zero-field splitting tensor D = -0.49 cm-1, E/D ≈ 0.055. Analysis of magnetic susceptibility, magnetization, and magneto-structural correlations further corroborate the presence of a sextet ground-spin state. The observed ground state originates from the strong anti-ferromagnetic interaction of two iron(III) spins, with J = 115(5) cm-1, that, in turn, are only weakly coupled to the spin of the third site, with j = 7(1) cm-1. These exchange interactions lead to a ground state with magnetic properties that are essentially entirely determined by the weakly coupled site. The contributions of the individual spins to the total ground state of the cluster were monitored using variable-field 57Fe Mössbauer spectroscopy. Field-dependent spectra reveal that, while one of the iron sites exhibits a large negative internal field, typical of ferric ions, the other two sites exhibit small, but not null, negative and positive internal fields. A theoretical analysis reveals that these small internal fields originate from the mixing of the lowest ST = 5/2 excited state into the ground state which, in turn, is induced by a minute structural distortion.
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Affiliation(s)
| | - Yi-Ru Peng
- Department of Chemistry, Fu Jen Catholic University , Hsinchuang, New Taipei City, 24205 Taiwan, Republic of China
| | | | - Yi-Jung Chung
- Department of Chemistry, Fu Jen Catholic University , Hsinchuang, New Taipei City, 24205 Taiwan, Republic of China
| | - Gene-Hsiang Lee
- Instrumentation Centre, College of Science, National Taiwan University , Taipei, 106 Taiwan, Republic of China
| | - En-Che Yang
- Department of Chemistry, Fu Jen Catholic University , Hsinchuang, New Taipei City, 24205 Taiwan, Republic of China
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15
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The ins and outs of cyclic di-GMP signaling in Vibrio cholerae. Curr Opin Microbiol 2017; 36:20-29. [PMID: 28171809 DOI: 10.1016/j.mib.2017.01.002] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 12/26/2016] [Accepted: 01/06/2017] [Indexed: 11/20/2022]
Abstract
The second messenger nucleotide cyclic dimeric guanosine monophosphate (c-di-GMP) governs many cellular processes in the facultative human pathogen Vibrio cholerae. This organism copes with changing environmental conditions in aquatic environments and during transitions to and from human hosts. Modulation of c-di-GMP allows V. cholerae to shift between motile and sessile stages of life, thus allowing adaptation to stressors and environmental conditions during its transmission cycle. The V. cholerae genome encodes a large set of proteins predicted to degrade and produce c-di-GMP. A subset of these enzymes has been demonstrated to control cellular processes - particularly motility, biofilm formation, and virulence - through transcriptional, post-transcriptional, and translational mechanisms. Recent studies have identified and characterized enzymes that modulate or sense c-di-GMP levels and have led towards mechanistic understanding of c-di-GMP regulatory circuits in V. cholerae.
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16
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Abstract
Haem-based sensors have emerged during the last 15 years as being a large family of proteins that occur in all kingdoms of life. These sensors are responsible mainly for detecting binding of O2, CO and NO and reporting the ligation status to an output domain with an enzymatic or macromolecule-binding property. A myriad of biological functions have been associated with these sensors, which are involved in vasodilation, bacterial symbiosis, chemotaxis and biofilm formation, among others. Here, we critically review several bacterial systems for O2 sensing that are extensively studied in many respects, focusing on the lessons that are important to advance the field.
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17
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Schirmer T. C-di-GMP Synthesis: Structural Aspects of Evolution, Catalysis and Regulation. J Mol Biol 2016; 428:3683-701. [PMID: 27498163 DOI: 10.1016/j.jmb.2016.07.023] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 07/30/2016] [Accepted: 07/31/2016] [Indexed: 10/21/2022]
Abstract
Cellular levels of the second messenger cyclic di-guanosine monophosphate (c-di-GMP) are determined by the antagonistic activities of diguanylate cyclases and specific phosphodiesterases. In a given bacterial organism, there are often multiple variants of the two enzymes, which are tightly regulated by a variety of external and internal cues due to the presence of specialized sensory or regulatory domains. Dependent on the second messenger level, specific c-di-GMP receptors then control fundamental cellular processes, such as bacterial life style, biofilm formation, and cell cycle control. Here, I review the large body of data on structure-function relationships in diguanylate cyclases. Although the catalytic GGDEF domain is related to the respective domain of adenylate cyclases, the catalyzed intermolecular condensation reaction of two GTP molecules requires the formation of a competent GGDEF dimer with the two substrate molecules juxtaposed. This prerequisite appears to constitute the basis for GGDEF regulation with signal-induced changes within the homotypic dimer of the input domain (PAS, GAF, HAMP, etc.), which are structurally coupled with the arrangement of the GGDEF domains via a rigid coiled-coil linker. Alternatively, phosphorylation of a Rec input domain can drive GGDEF dimerization. Both mechanisms allow modular combination of input and output function that appears advantageous for evolution and rationalizes the striking similarities in domain architecture found in diguanylate cyclases and histidine kinases.
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Affiliation(s)
- Tilman Schirmer
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland.
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18
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Microbial Surface Colonization and Biofilm Development in Marine Environments. Microbiol Mol Biol Rev 2015; 80:91-138. [PMID: 26700108 DOI: 10.1128/mmbr.00037-15] [Citation(s) in RCA: 488] [Impact Index Per Article: 54.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Biotic and abiotic surfaces in marine waters are rapidly colonized by microorganisms. Surface colonization and subsequent biofilm formation and development provide numerous advantages to these organisms and support critical ecological and biogeochemical functions in the changing marine environment. Microbial surface association also contributes to deleterious effects such as biofouling, biocorrosion, and the persistence and transmission of harmful or pathogenic microorganisms and their genetic determinants. The processes and mechanisms of colonization as well as key players among the surface-associated microbiota have been studied for several decades. Accumulating evidence indicates that specific cell-surface, cell-cell, and interpopulation interactions shape the composition, structure, spatiotemporal dynamics, and functions of surface-associated microbial communities. Several key microbial processes and mechanisms, including (i) surface, population, and community sensing and signaling, (ii) intraspecies and interspecies communication and interaction, and (iii) the regulatory balance between cooperation and competition, have been identified as critical for the microbial surface association lifestyle. In this review, recent progress in the study of marine microbial surface colonization and biofilm development is synthesized and discussed. Major gaps in our knowledge remain. We pose questions for targeted investigation of surface-specific community-level microbial features, answers to which would advance our understanding of surface-associated microbial community ecology and the biogeochemical functions of these communities at levels from molecular mechanistic details through systems biological integration.
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19
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Differential roles of the hemerythrin-like proteins of Mycobacterium smegmatis in hydrogen peroxide and erythromycin susceptibility. Sci Rep 2015; 5:16130. [PMID: 26607739 PMCID: PMC4660385 DOI: 10.1038/srep16130] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 10/08/2015] [Indexed: 11/09/2022] Open
Abstract
Hemerythrin-like proteins are oxygen-carrying non-heme di-iron binding proteins and their functions have effect on oxidation-reduction regulation and antibiotic resistance. Recent studies using bioinformatic analyses suggest that multiple hemerythrin-like protein coding sequences might have been acquired by lateral gene transfer and the number of hemerythrin-like proteins varies amongst different species. Mycobacterium smegmatis contains three hemerythrin-like proteins, MSMEG_3312, MSMEG_2415 and MSMEG_6212. In this study, we have systematically analyzed all three hemerythrin-like proteins in M. smegmatis and our results identified and characterized two functional classes: MSMEG_2415 plays an important role in H2O2 susceptibility, and MSMEG_3312 and MSMEG_6212 are associated with erythromycin susceptibility. Phylogenetic analysis indicated that these three proteins have different evolutionary origins, possibly explaining their different physiological functions. Here, combined with biological and phylogenetic analyses, our results provide new insights into the evolutionary divergence of the hemerythrin-like proteins in M. smegmatis.
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20
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Frederick RE, Caranto JD, Masitas CA, Gebhardt LL, MacGowan CE, Limberger RJ, Kurtz DM. Dioxygen and nitric oxide scavenging by Treponema denticola flavodiiron protein: a mechanistic paradigm for catalysis. J Biol Inorg Chem 2015; 20:603-13. [PMID: 25700637 PMCID: PMC4768905 DOI: 10.1007/s00775-015-1248-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 02/13/2015] [Indexed: 10/24/2022]
Abstract
Flavodiiron proteins (FDPs) contain a unique active site consisting of a non-heme diiron carboxylate site proximal to a flavin mononucleotide (FMN). FDPs serve as the terminal components for reductive scavenging of dioxygen (to water) or nitric oxide (to nitrous oxide), which combats oxidative or nitrosative stress in many bacteria. Characterizations of FDPs from spirochetes or from any oral microbes have not been previously reported. Here, we report characterization of an FDP from the anaerobic spirochete, Treponema (T.) denticola, which is associated with chronic periodontitis. The isolated T. denticola FDP exhibited efficient four-electron dioxygen reductase activity and lower but significant anaerobic nitric oxide reductase activity. A mutant T. denticola strain containing the inactivated FDP-encoding gene was significantly more air-sensitive than the wild-type strain. Single turnover reactions of the four-electron-reduced FDP (FMNH2-Fe(II)Fe(II)) (FDPred) with O2 monitored on the milliseconds to seconds time scale indicated initial rapid formation of a spectral feature consistent with a cis-μ-1,2-peroxo-diferric intermediate, which triggered two-electron oxidation of FMNH2. Reaction of FDPred with NO showed apparent cooperativity between binding of the first and second NO to the diferrous site. The resulting diferrous dinitrosyl complex triggered two-electron oxidation of the FMNH2. Our cumulative results on this and other FDPs indicate that smooth two-electron FMNH2 oxidation triggered by the FDPred/substrate complex and overall four-electron oxidation of FDPred to FDPox constitutes a mechanistic paradigm for both dioxygen and nitric oxide reductase activities of FDPs. Four-electron reductive O2 scavenging by FDPs could contribute to oxidative stress protection in many other oral bacteria.
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Affiliation(s)
- Rosanne E. Frederick
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Jonathan D. Caranto
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Cesar A. Masitas
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Linda L. Gebhardt
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA
| | - Charles E. MacGowan
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA
| | - Ronald J. Limberger
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA
| | - Donald M. Kurtz
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, USA
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21
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Townsley L, Yildiz FH. Temperature affects c-di-GMP signalling and biofilm formation in Vibrio cholerae. Environ Microbiol 2015; 17:4290-305. [PMID: 25684220 DOI: 10.1111/1462-2920.12799] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 01/19/2015] [Accepted: 01/31/2015] [Indexed: 02/04/2023]
Abstract
Biofilm formation is crucial to the environmental survival and transmission of Vibrio cholerae, the facultative human pathogen responsible for the disease cholera. During its infectious cycle, V. cholerae experiences fluctuations in temperature within the aquatic environment and during the transition between human host and aquatic reservoirs. In this study, we report that biofilm formation is induced at low temperatures through increased levels of the signalling molecule, cyclic diguanylate (c-di-GMP). Strains harbouring in frame deletions of all V. cholerae genes that are predicted to encode diguanylate cyclases (DGCs) or phosphodiesterases (PDEs) were screened for their involvement in low-temperature-induced biofilm formation and Vibrio polysaccharide gene expression. Of the 52 mutants tested, deletions of six DGCs and three PDEs were found to affect these phenotypes at low temperatures. Unlike wild type, a strain lacking all six DGCs did not exhibit a low-temperature-dependent increase in c-di-GMP, indicating that these DGCs are required for temperature modulation of c-di-GMP levels. We also show that temperature modulates c-di-GMP levels in a similar fashion in the Gram-negative pathogen Pseudomonas aeruginosa but not in the Gram-positive pathogen Listeria monocytogenes. This study uncovers the role of temperature in environmental regulation of biofilm formation and c-di-GMP signalling.
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Affiliation(s)
- Loni Townsley
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA, 95064, USA
| | - Fitnat H Yildiz
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA, 95064, USA
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22
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Li X, Tao J, Hu X, Chan J, Xiao J, Mi K. A bacterial hemerythrin-like protein MsmHr inhibits the SigF-dependent hydrogen peroxide response in mycobacteria. Front Microbiol 2015; 5:800. [PMID: 25642228 PMCID: PMC4295536 DOI: 10.3389/fmicb.2014.00800] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 12/27/2014] [Indexed: 12/05/2022] Open
Abstract
Hydrogen peroxide (H2O2) is one of a variety of reactive oxygen species (ROS) produced by aerobic organisms. Host production of toxic H2O2 in response to pathogen infection is an important classical innate defense mechanism against invading microbes. Understanding the mechanisms by which pathogens, in response to oxidative stress, mediate defense against toxic ROS, can reveal anti-microbial targets and shed light on pathogenic mechanisms. In this study, we provide evidence that a Mycobacterium smegmatis hemerythrin-like protein MSMEG_2415, designated MsmHr, is a H2O2-modulated repressor of the SigF-mediated response to H2O2. Circular dichroism and spectrophotometric analysis of MsmHr revealed properties characteristic of a typical hemerythrin-like protein. An msmHr knockout strain of M. smegmatis mc2155 (ΔmsmHr) was more resistant to H2O2 than its parental strain, and overexpression of MsmHr increased mycobacterial susceptibility to H2O2. Mutagenesis studies revealed that the hemerythrin domain of MsmHr is required for the regulation of the H2O2 response observed in the overexpression study. We show that MsmHr inhibits the expression of SigF (MSMEG_1804), an alternative sigma factor that plays an important role in bacterial oxidative stress responses, including those elicited by H2O2, thus providing a mechanistic link between ΔmsmHr and its enhanced resistance to H2O2. Together, these results strongly suggest that MsmHr is involved in the response of mycobacteria to H2O2 by negatively regulating a sigma factor, a function not previously described for hemerythrins.
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Affiliation(s)
- Xiaojing Li
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences Beijing, China
| | - Jun Tao
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences Beijing, China
| | - Xinling Hu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences Beijing, China
| | - John Chan
- Departments of Medicine and Microbiology and Immunology, Albert Einstein College of Medicine Bronx, NY, USA
| | - Jing Xiao
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences Beijing, China
| | - Kaixia Mi
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences Beijing, China ; Beijing Key Laboratory of Microbial Drug Resistance and Resistome Beijing, China
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23
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Abstract
The haem-based sensors are chimeric multi-domain proteins responsible for the cellular adaptive responses to environmental changes. The signal transduction is mediated by the sensing capability of the haem-binding domain, which transmits a usable signal to the cognate transmitter domain, responsible for providing the adequate answer. Four major families of haem-based sensors can be recognized, depending on the nature of the haem-binding domain: (i) the haem-binding PAS domain, (ii) the CO-sensitive carbon monoxide oxidation activator, (iii) the haem NO-binding domain, and (iv) the globin-coupled sensors. The functional classification of the haem-binding sensors is based on the activity of the transmitter domain and, traditionally, comprises: (i) sensors with aerotactic function; (ii) sensors with gene-regulating function; and (iii) sensors with unknown function. We have implemented this classification with newly identified proteins, that is, the Streptomyces avermitilis and Frankia sp. that present a C-terminal-truncated globin fused to an N-terminal cofactor-free monooxygenase, the structural-related class of non-haem globins in Bacillus subtilis, Moorella thermoacetica, and Bacillus anthracis, and a haemerythrin-coupled diguanylate cyclase in Vibrio cholerae. This review summarizes the structures, the functions, and the structure-function relationships known to date on this broad protein family. We also propose unresolved questions and new possible research approaches.
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24
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Taabazuing CY, Hangasky JA, Knapp MJ. Oxygen sensing strategies in mammals and bacteria. J Inorg Biochem 2014; 133:63-72. [PMID: 24468676 PMCID: PMC4097052 DOI: 10.1016/j.jinorgbio.2013.12.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 12/23/2013] [Accepted: 12/24/2013] [Indexed: 12/21/2022]
Abstract
The ability to sense and adapt to changes in pO2 is crucial for basic metabolism in most organisms, leading to elaborate pathways for sensing hypoxia (low pO2). This review focuses on the mechanisms utilized by mammals and bacteria to sense hypoxia. While responses to acute hypoxia in mammalian tissues lead to altered vascular tension, the molecular mechanism of signal transduction is not well understood. In contrast, chronic hypoxia evokes cellular responses that lead to transcriptional changes mediated by the hypoxia inducible factor (HIF), which is directly controlled by post-translational hydroxylation of HIF by the non-heme Fe(II)/αKG-dependent enzymes FIH and PHD2. Research on PHD2 and FIH is focused on developing inhibitors and understanding the links between HIF binding and the O2 reaction in these enzymes. Sulfur speciation is a putative mechanism for acute O2-sensing, with special focus on the role of H2S. This sulfur-centered model is discussed, as are some of the directions for further refinement of this model. In contrast to mammals, bacterial O2-sensing relies on protein cofactors that either bind O2 or oxidatively decompose. The sensing modality for bacterial O2-sensors is either via altered DNA binding affinity of the sensory protein, or else due to the actions of a two-component signaling cascade. Emerging data suggests that proteins containing a hemerythrin-domain, such as FBXL5, may serve to connect iron sensing to O2-sensing in both bacteria and humans. As specific molecular machinery becomes identified, these hypoxia sensing pathways present therapeutic targets for diseases including ischemia, cancer, or bacterial infection.
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Affiliation(s)
| | - John A Hangasky
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, United States
| | - Michael J Knapp
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, United States.
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25
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Kendall JJ, Barrero-Tobon AM, Hendrixson DR, Kelly DJ. Hemerythrins in the microaerophilic bacterium Campylobacter jejuni help protect key iron-sulphur cluster enzymes from oxidative damage. Environ Microbiol 2013; 16:1105-21. [PMID: 24245612 PMCID: PMC4257069 DOI: 10.1111/1462-2920.12341] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 11/12/2013] [Indexed: 01/27/2023]
Abstract
Microaerophilic bacteria are adapted to low oxygen environments, but the mechanisms by which their growth in air is inhibited are not well understood. The citric acid cycle in the microaerophilic pathogen Campylobacter jejuni is potentially vulnerable, as it employs pyruvate and 2-oxoglutarate:acceptor oxidoreductases (Por and Oor), which contain labile (4Fe-4S) centres. Here, we show that both enzymes are rapidly inactivated after exposure of cells to a fully aerobic environment. We investigated the mechanisms that might protect enzyme activity and identify a role for the hemerythrin HerA (Cj0241). A herA mutant exhibits an aerobic growth defect and reduced Por and Oor activities after exposure to 21% (v/v) oxygen. Slow anaerobic recovery of these activities after oxygen damage was observed, but at similar rates in both wild-type and herA strains, suggesting the role of HerA is to prevent Fe-S cluster damage, rather than promote repair. Another hemerythrin (HerB; Cj1224) also plays a protective role. Purified HerA and HerB exhibited optical absorption, ligand binding and resonance Raman spectra typical of μ-oxo-bridged di-iron containing hemerythrins. We conclude that oxygen lability and poor repair of Por and Oor are major contributors to microaerophily in C. jejuni; hemerythrins help prevent enzyme damage microaerobically or during oxygen transients.
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Affiliation(s)
- John J Kendall
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield, UK
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26
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Miner KD, Klose KE, Kurtz DM. An HD-GYP cyclic di-guanosine monophosphate phosphodiesterase with a non-heme diiron-carboxylate active site. Biochemistry 2013; 52:5329-31. [PMID: 23883166 DOI: 10.1021/bi4009215] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The intracellular level of the ubiquitous bacterial secondary messenger, cyclic di-(3',5')-guanosine monophosphate (c-di-GMP), represents a balance between its biosynthesis and degradation, the latter via specific phosphodiesterases (PDEs). One class of c-di-GMP PDEs contains a characteristic HD-GYP domain. Here we report that an HD-GYP PDE from Vibrio cholerae contains a non-heme diiron-carboxylate active site, and that only the reduced form is active. An engineered D-to-A substitution in the HD dyad caused loss of c-di-GMP PDE activity and of two iron atoms. This report constitutes the first demonstration that a non-heme diiron-carboxylate active site can catalyze the c-di-GMP PDE reaction and that this activity can be redox regulated in the HD-GYP class.
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Affiliation(s)
- Kyle D Miner
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, USA
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