1
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Ye D, Nguyen PT, Bourgault S, Couture M. The heme binding protein ChuX is a regulator of heme degradation by the ChuS protein in Escherichia coli O157:H7. J Inorg Biochem 2024; 256:112575. [PMID: 38678912 DOI: 10.1016/j.jinorgbio.2024.112575] [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: 03/01/2024] [Revised: 04/17/2024] [Accepted: 04/23/2024] [Indexed: 05/01/2024]
Abstract
Escherichia coli O157:H7 possesses an 8-gene cluster (chu genes) that contains genes involved in heme transport and processing from the human host. Among the chu genes, four encode cytoplasmic proteins (ChuS, ChuX, ChuY and ChuW). ChuX was previously shown to be a heme binding protein and to assist ChuW in heme degradation under anaerobic conditions. The purpose of this work was to investigate if ChuX works in concert with ChuS, which is a protein able to degrade heme by a non-canonical mechanism and release the iron from the porphyrin under aerobic conditions using hydrogen peroxide as the oxidant. We showed that when the heme-bound ChuX and apo-ChuS protein are mixed, heme is efficiently transferred from ChuX to ChuS. Heme-bound ChuX displayed a peroxidase activity with ABTS and H2O2 but not heme-bound ChuS, which is an efficient test to determine the protein to which heme is bound in the ChuS-ChuX complex. We found that ChuX protects heme from chemical oxidation and that it has no heme degradation activity by itself. Unexpectedly, we found that ChuX inhibits heme degradation by ChuS and stops the reaction at an early intermediate. We determined using surface plasmon resonance that ChuX interacts with ChuS and that it forms a relatively stable complex. These results indicate that ChuX in addition to its heme transfer activity is a regulator of ChuS activity, a function that was not described before for any of the heme carrier protein that delivers heme to heme degradation enzymes.
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Affiliation(s)
- Danrong Ye
- Department of Biochemistry, Microbiology and Bioinformatics, Université Laval, Quebec City, QC, Canada; Institut de Biologie Intégrative et des Systèmes (IBIS) and PROTEO, Université Laval, Quebec city, QC, Canada; Quebec Network for Research on Protein Function, Engineering and Applications (PROTEO), Montreal, QC, Canada
| | - Phuong Trang Nguyen
- Quebec Network for Research on Protein Function, Engineering and Applications (PROTEO), Montreal, QC, Canada; Departement of Chemistry, Université du Québec à Montréal, Montreal, QC, Canada
| | - Steve Bourgault
- Quebec Network for Research on Protein Function, Engineering and Applications (PROTEO), Montreal, QC, Canada; Departement of Chemistry, Université du Québec à Montréal, Montreal, QC, Canada
| | - Manon Couture
- Department of Biochemistry, Microbiology and Bioinformatics, Université Laval, Quebec City, QC, Canada; Institut de Biologie Intégrative et des Systèmes (IBIS) and PROTEO, Université Laval, Quebec city, QC, Canada; Quebec Network for Research on Protein Function, Engineering and Applications (PROTEO), Montreal, QC, Canada.
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2
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James A, Li G, List R, Lonabaugh K, Smith AD, Barros A, Somerville L, Albon D. Analysis of iron status after initiation of elexacaftor/tezacaftor/ivacaftor in people with cystic fibrosis. Pediatr Pulmonol 2024; 59:669-678. [PMID: 38088203 DOI: 10.1002/ppul.26805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 11/08/2023] [Accepted: 11/27/2023] [Indexed: 02/16/2024]
Abstract
BACKGROUND Iron deficiency is highly prevalent in people with cystic fibrosis (PwCF). While elexacaftor/tezacaftor/ivacaftor (ETI) has shown remarkable improvements in respiratory symptoms in PwCF, the effect of ETI on iron status remains unknown. This study aims to identify the effect of ETI on iron status in PwCF. METHODS A single-center retrospective cohort study of 127 adult PwCF was conducted to assess the impact of ETI on iron, ferritin, transferrin levels, and percent saturation of transferrin (PSAT). Data were collected from the electronic medical record from January 2017 to September 2022, encompassing 2 years before and after ETI initiation. The primary outcome was serum iron parameters: iron, ferritin, transferrin, and PSAT levels following ETI treatment. Secondary outcomes analyzed iron supplementation. Univariate and multivariate mixed-effects models were used for the analysis of ETI. RESULTS After adjusting for covariates, following ETI initiation, the mean iron level increased by 20.24 μg/dL (p < .001), ferritin levels were 31.4% (p < .001) higher, PSAT showed a 5.09 percentage point increase (p < .001), and transferrin levels increased by 2.71 mg/dL (p = .439). Patients with and without iron supplementation experienced a significant increase in iron after ETI (p < .001). CONCLUSIONS ETI is associated with a significant increase in iron, ferritin, and PSAT levels. Patients with and without iron supplementation demonstrated a significant increase in iron. This study shows the benefits of ETI on iron status in PwCF. However, further translational studies are required to understand the impact of ETI on iron absorption and metabolism in PwCF.
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Affiliation(s)
- Amber James
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Galvin Li
- Department of Statistics, University of Virginia, Charlottesville, Virginia, USA
| | - Rhonda List
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Kevin Lonabaugh
- Department of Medicine, Division of Pulmonology and Critical Care Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Aaron D Smith
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Andrew Barros
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- Department of Medicine, Division of Pulmonology and Critical Care Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Lindsay Somerville
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- Department of Medicine, Division of Pulmonology and Critical Care Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Dana Albon
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- Department of Medicine, Division of Pulmonology and Critical Care Medicine, University of Virginia, Charlottesville, Virginia, USA
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3
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Keith AD, Sawyer EB, Choy DCY, Xie Y, Biggs GS, Klein OJ, Brear PD, Wales DJ, Barker PD. Combining experiment and energy landscapes to explore anaerobic heme breakdown in multifunctional hemoproteins. Phys Chem Chem Phys 2024; 26:695-712. [PMID: 38053511 DOI: 10.1039/d3cp03897a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
To survive, many pathogens extract heme from their host organism and break down the porphyrin scaffold to sequester the Fe2+ ion via a heme oxygenase. Recent studies have revealed that certain pathogens can anaerobically degrade heme. Our own research has shown that one such pathway proceeds via NADH-dependent heme degradation, which has been identified in a family of hemoproteins from a range of bacteria. HemS, from Yersinia enterocolitica, is the main focus of this work, along with HmuS (Yersinia pestis), ChuS (Escherichia coli) and ShuS (Shigella dysenteriae). We combine experiments, Energy Landscape Theory, and a bioinformatic investigation to place these homologues within a wider phylogenetic context. A subset of these hemoproteins are known to bind certain DNA promoter regions, suggesting not only that they can catalytically degrade heme, but that they are also involved in transcriptional modulation responding to heme flux. Many of the bacterial species responsible for these hemoproteins (including those that produce HemS, ChuS and ShuS) are known to specifically target oxygen-depleted regions of the gastrointestinal tract. A deeper understanding of anaerobic heme breakdown processes exploited by these pathogens could therefore prove useful in the development of future strategies for disease prevention.
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Affiliation(s)
- Alasdair D Keith
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
| | - Elizabeth B Sawyer
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
| | - Desmond C Y Choy
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
| | - Yuhang Xie
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
| | - George S Biggs
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
| | - Oskar James Klein
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
| | - Paul D Brear
- Department of Biochemistry, University of Cambridge, Sanger Building, Cambridge CB2 1GA, UK
| | - David J Wales
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
| | - Paul D Barker
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
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4
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Donegan RK. The role of host heme in bacterial infection. Biol Chem 2022; 403:1017-1029. [PMID: 36228088 DOI: 10.1515/hsz-2022-0192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Accepted: 09/14/2022] [Indexed: 11/15/2022]
Abstract
Heme is an indispensable cofactor for almost all aerobic life, including the human host and many bacterial pathogens. During infection, heme and hemoproteins are the largest source of bioavailable iron, and pathogens have evolved various heme acquisition pathways to satisfy their need for iron and heme. Many of these pathways are regulated transcriptionally by intracellular iron levels, however, host heme availability and intracellular heme levels have also been found to regulate heme uptake in some species. Knowledge of these pathways has helped to uncover not only how these bacteria incorporate host heme into their metabolism but also provided insight into the importance of host heme as a nutrient source during infection. Within this review is covered multiple aspects of the role of heme at the host pathogen interface, including the various routes of heme biosynthesis, how heme is sequestered by the host, and how heme is scavenged by bacterial pathogens. Also discussed is how heme and hemoproteins alter the behavior of the host immune system and bacterial pathogens. Finally, some unanswered questions about the regulation of heme uptake and how host heme is integrated into bacterial metabolism are highlighted.
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Affiliation(s)
- Rebecca K Donegan
- Department of Chemistry, Barnard College, 3009 Broadway, New York, NY, 10027, USA
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5
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Huo H, Zong L, Liu Y, Chen W, Chen J, Wei G. Rhizobial HmuS pSym as a heme-binding factor is required for optimal symbiosis between Mesorhizobium amorphae CCNWGS0123 and Robinia pseudoacacia. PLANT, CELL & ENVIRONMENT 2022; 45:2191-2210. [PMID: 35419804 DOI: 10.1111/pce.14335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 01/15/2022] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
Nitrogen-fixing root nodules are formed by symbiotic association of legume hosts with rhizobia in nitrogen-deprived soils. Successful symbiosis is regulated by signals from both legume hosts and their rhizobial partners. HmuS is a heme degrading factor widely distributed in bacteria, but little is known about the role of rhizobial hmuS in symbiosis with legumes. Here, we found that inactivation of hmuSpSym in the symbiotic plasmid of Mesorhizobium amorphae CCNWGS0123 disrupted rhizobial infection, primordium formation, and nitrogen fixation in symbiosis with Robinia pseudoacacia. Although there was no difference in bacteroids differentiation, infected plant cells were shrunken and bacteroids were disintegrated in nodules of plants infected by the ΔhmuSpSym mutant strain. The balance of defence reaction was also impaired in ΔhmuSpSym strain-infected root nodules. hmuSpSym was strongly expressed in the nitrogen-fixation zone of mature nodules. Furthermore, the HmuSpSym protein could bind to heme but not degrade it. Inactivation of hmuSpSym led to significantly decreased expression levels of oxygen-sensing related genes in nodules. In summary, hmuSpSym of M. amorphae CCNWGS0123 plays an essential role in nodule development and maintenance of bacteroid survival within R. pseudoacacia cells, possibly through heme-binding in symbiosis.
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Affiliation(s)
- Haibo Huo
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Science, Northwest A&F University, Yangling, Shaanxi, China
| | - Le Zong
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Science, Northwest A&F University, Yangling, Shaanxi, China
| | - Yao Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Science, Northwest A&F University, Yangling, Shaanxi, China
| | - Wenfeng Chen
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences and Rhizobium Research Center, Ministry of Agriculture Key Laboratory of Soil Microbiology, China Agricultural University, Beijing, China
| | - Juan Chen
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi, China
| | - Gehong Wei
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Science, Northwest A&F University, Yangling, Shaanxi, China
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6
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Kihn KC, Wilson T, Smith AK, Bradshaw RT, Wintrode PL, Forrest LR, Wilks A, Deredge DJ. Modeling the native ensemble of PhuS using enhanced sampling MD and HDX-ensemble reweighting. Biophys J 2021; 120:5141-5157. [PMID: 34767787 PMCID: PMC8715216 DOI: 10.1016/j.bpj.2021.11.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 10/13/2021] [Accepted: 11/04/2021] [Indexed: 11/25/2022] Open
Abstract
The cytoplasmic heme binding protein from Pseudomonas aeruginosa, PhuS, plays two essential roles in regulating heme uptake and iron homeostasis. First, PhuS shuttles exogenous heme to heme oxygenase (HemO) for degradation and iron release. Second, PhuS binds DNA and modulates the transcription of the prrF/H small RNAs (sRNAs) involved in the iron-sparing response. Heme binding to PhuS regulates this dual function, as the unliganded form binds DNA, whereas the heme-bound form binds HemO. Crystallographic studies revealed nearly identical structures for apo- and holo-PhuS, and yet numerous solution-based measurements indicate that heme binding is accompanied by large conformational rearrangements. In particular, hydrogen-deuterium exchange mass spectrometry (HDX-MS) of apo- versus holo-PhuS revealed large differences in deuterium uptake, notably in α-helices 6, 7, and 8 (α6,7,8), which contribute to the heme binding pocket. These helices were mostly labile in apo-PhuS but largely protected in holo-PhuS. In contrast, in silico-predicted deuterium uptake levels of α6,7,8 from molecular dynamics (MD) simulations of the apo- and holo-PhuS structures are highly similar, consistent only with the holo-PhuS HDX-MS data. To rationalize this discrepancy between crystal structures, simulations, and observed HDX-MS, we exploit a recently developed computational approach (HDXer) that fits the relative weights of conformational populations within an ensemble of structures to conform to a target set of HDX-MS data. Here, a combination of enhanced sampling MD, HDXer, and dimensionality reduction analysis reveals an apo-PhuS conformational landscape in which α6, 7, and 8 are significantly rearranged compared to the crystal structure, including a loss of secondary structure in α6 and the displacement of α7 toward the HemO binding interface. Circular dichroism analysis confirms the loss of secondary structure, and the extracted ensembles of apo-PhuS and of heme-transfer-impaired H212R mutant, are consistent with known heme binding and transfer properties. The proposed conformational landscape provides structural insights into the modulation by heme of the dual function of PhuS.
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Affiliation(s)
- Kyle C Kihn
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland
| | - Tyree Wilson
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland
| | - Ally K Smith
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland
| | | | - Patrick L Wintrode
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland
| | - Lucy R Forrest
- Computational Structural Biology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - Angela Wilks
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland
| | - Daniel J Deredge
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland.
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7
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Extracellular haem utilization by the opportunistic pathogen Pseudomonas aeruginosa and its role in virulence and pathogenesis. Adv Microb Physiol 2021; 79:89-132. [PMID: 34836613 DOI: 10.1016/bs.ampbs.2021.07.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Iron is an essential micronutrient for all bacteria but presents a significant challenge given its limited bioavailability. Furthermore, iron's toxicity combined with the need to maintain iron levels within a narrow physiological range requires integrated systems to sense, regulate and transport a variety of iron complexes. Most bacteria encode systems to chelate and transport ferric iron (Fe3+) via siderophore receptor mediated uptake or via cytoplasmic energy dependent transport systems. Pathogenic bacteria have further lowered the barrier to iron acquisition by employing systems to utilize haem as a source of iron. Haem, a lipophilic and toxic molecule, presents a significant challenge for transport into the cell. As such pathogenic bacteria have evolved sophisticated cell surface signaling (CSS) and transport systems to sense and obtain haem from the host. Once internalized haem is cleaved by both oxidative and non-oxidative mechanisms to release iron. Herein we summarize our current understanding of the mechanism of haem sensing, uptake and utilization in Pseudomonas aeruginosa, its role in pathogenesis and virulence, and the potential of these systems as antimicrobial targets.
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8
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Dent AT, Brimberry M, Albert T, Lanzilotta WN, Moënne-Loccoz P, Wilks A. Axial Heme Coordination by the Tyr-His Motif in the Extracellular Hemophore HasAp Is Critical for the Release of Heme to the HasR Receptor of Pseudomonas aeruginosa. Biochemistry 2021; 60:2549-2559. [PMID: 34324310 DOI: 10.1021/acs.biochem.1c00389] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pseudomonas aeruginosa senses extracellular heme via an extra cytoplasmic function σ factor that is activated upon interaction of the hemophore holo-HasAp with the HasR receptor. Herein, we show Y75H holo-HasAp interacts with HasR but is unable to release heme for signaling and uptake. To understand this inhibition, we undertook a spectroscopic characterization of Y75H holo-HasAp by resonance Raman (RR), electron paramagnetic resonance (EPR), and X-ray crystallography. The RR spectra are consistent with a mixed six-coordinate high-spin (6cHS), six-coordinate low-spin (6cLS) heme configuration and an H218O exchangeable FeIII-O stretching frequency with 16O/18O and H/D isotope shifts that support a two-body Fe-OH2 oscillator with (iron-hydroxy)-like character as both hydrogen atoms are engaged in short hydrogen bond interactions with protein side chains. Further support comes from the EPR spectrum of Y75H holo-HasAp that shows a LS rhombic signal with ligand-field splitting values intermediate between those of His-hydroxy and bis-His ferric hemes. The crystal structure of Y75H holo-HasAp confirmed the coordinated solvent molecule hydrogen bonded through H75 and H83. The long-range conformational rearrangement of HasAp upon heme binding can still take place in Y75H holo-HasAp, because the intercalation of a hydroxy ligand between the heme iron and H75 allows the variant to reproduce the heme binding pocket observed in wild-type holo-HasAp. However, in the absence of a covalent linkage to the Y75 loop combined with the malleability provided by the bracketing H75 and H83 hydrogen bonds, either the hydroxy sixth ligand remains bound after complexation of Y75H holo-HasAp with HasR or rearrangement and coordination of H85 prevent heme transfer.
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Affiliation(s)
- Alecia T Dent
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, 20 Penn Street, Baltimore, Maryland 21201, United States
| | - Marley Brimberry
- Department of Biochemistry and Molecular Biology, Franklin College of Arts and Sciences, University of Georgia, Athens, Georgia 30602, United States
| | - Therese Albert
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health & Science University, Portland, Oregon 97239, United States
| | - William N Lanzilotta
- Department of Biochemistry and Molecular Biology, Franklin College of Arts and Sciences, University of Georgia, Athens, Georgia 30602, United States
| | - Pierre Moënne-Loccoz
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health & Science University, Portland, Oregon 97239, United States
| | - Angela Wilks
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, 20 Penn Street, Baltimore, Maryland 21201, United States
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9
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Traore ES, Li J, Chiura T, Geng J, Sachla AJ, Yoshimoto F, Eichenbaum Z, Davis I, Mak PJ, Liu A. Heme Binding to HupZ with a C-Terminal Tag from Group A Streptococcus. Molecules 2021; 26:549. [PMID: 33494451 PMCID: PMC7865249 DOI: 10.3390/molecules26030549] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/14/2021] [Accepted: 01/16/2021] [Indexed: 12/23/2022] Open
Abstract
HupZ is an expected heme degrading enzyme in the heme acquisition and utilization pathway in Group A Streptococcus. The isolated HupZ protein containing a C-terminal V5-His6 tag exhibits a weak heme degradation activity. Here, we revisited and characterized the HupZ-V5-His6 protein via biochemical, mutagenesis, protein quaternary structure, UV-vis, EPR, and resonance Raman spectroscopies. The results show that the ferric heme-protein complex did not display an expected ferric EPR signal and that heme binding to HupZ triggered the formation of higher oligomeric states. We found that heme binding to HupZ was an O2-dependent process. The single histidine residue in the HupZ sequence, His111, did not bind to the ferric heme, nor was it involved with the weak heme-degradation activity. Our results do not favor the heme oxygenase assignment because of the slow binding of heme and the newly discovered association of the weak heme degradation activity with the His6-tag. Altogether, the data suggest that the protein binds heme by its His6-tag, resulting in a heme-induced higher-order oligomeric structure and heme stacking. This work emphasizes the importance of considering exogenous tags when interpreting experimental observations during the study of heme utilization proteins.
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Affiliation(s)
- Ephrahime S. Traore
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 78249, USA; (E.S.T.); (J.L.); (F.Y.); (I.D.)
| | - Jiasong Li
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 78249, USA; (E.S.T.); (J.L.); (F.Y.); (I.D.)
| | - Tapiwa Chiura
- Department of Chemistry, Saint Louis University, St. Louis, MO 63103, USA;
| | - Jiafeng Geng
- Department of Chemistry, Georgia State University, Atlanta, GA 30302, USA;
| | - Ankita J. Sachla
- Department of Biology, Georgia State University, Atlanta, GA 30302, USA; (A.J.S.); (Z.E.)
| | - Francis Yoshimoto
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 78249, USA; (E.S.T.); (J.L.); (F.Y.); (I.D.)
| | - Zehava Eichenbaum
- Department of Biology, Georgia State University, Atlanta, GA 30302, USA; (A.J.S.); (Z.E.)
| | - Ian Davis
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 78249, USA; (E.S.T.); (J.L.); (F.Y.); (I.D.)
- Department of Chemistry, Georgia State University, Atlanta, GA 30302, USA;
| | - Piotr J. Mak
- Department of Chemistry, Saint Louis University, St. Louis, MO 63103, USA;
| | - Aimin Liu
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 78249, USA; (E.S.T.); (J.L.); (F.Y.); (I.D.)
- Department of Chemistry, Georgia State University, Atlanta, GA 30302, USA;
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10
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Wilson T, Mouriño S, Wilks A. The heme-binding protein PhuS transcriptionally regulates the Pseudomonas aeruginosa tandem sRNA prrF1,F2 locus. J Biol Chem 2021; 296:100275. [PMID: 33428928 PMCID: PMC7948967 DOI: 10.1016/j.jbc.2021.100275] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 01/04/2021] [Accepted: 01/07/2021] [Indexed: 11/18/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen requiring iron for its survival and virulence. P. aeruginosa can acquire iron from heme via the nonredundant heme assimilation system and Pseudomonas heme uptake (Phu) systems. Heme transported by either the heme assimilation system or Phu system is sequestered by the cytoplasmic protein PhuS. Furthermore, PhuS has been shown to specifically transfer heme to the iron-regulated heme oxygenase HemO. As the PhuS homolog ShuS from Shigella dysenteriae was observed to bind DNA as a function of its heme status, we sought to further determine if PhuS, in addition to its role in regulating heme flux through HemO, functions as a DNA-binding protein. Herein, through a combination of chromatin immunoprecipitation–PCR, EMSA, and fluorescence anisotropy, we show that apo-PhuS but not holo-PhuS binds upstream of the tandem iron-responsive sRNAs prrF1,F2. Previous studies have shown the PrrF sRNAs are required for sparing iron for essential proteins during iron starvation. Furthermore, under certain conditions, a heme-dependent read through of the prrF1 terminator yields the longer PrrH transcript. Quantitative PCR analysis of P. aeruginosa WT and ΔphuS strains shows that loss of PhuS abrogates the heme-dependent regulation of PrrF and PrrH levels. Taken together, our data show that PhuS, in addition to its role in extracellular heme metabolism, also functions as a transcriptional regulator by modulating PrrF and PrrH levels in response to heme. This dual function of PhuS is central to integrating extracellular heme utilization into the PrrF/PrrH sRNA regulatory network that is critical for P. aeruginosa adaptation and virulence within the host.
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Affiliation(s)
- Tyree Wilson
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
| | - Susana Mouriño
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
| | - Angela Wilks
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA.
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11
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Mobilization of Iron Stored in Bacterioferritin Is Required for Metabolic Homeostasis in Pseudomonas aeruginosa. Pathogens 2020; 9:pathogens9120980. [PMID: 33255203 PMCID: PMC7760384 DOI: 10.3390/pathogens9120980] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/22/2020] [Accepted: 11/23/2020] [Indexed: 12/12/2022] Open
Abstract
Iron homeostasis offers a significant bacterial vulnerability because pathogens obtain essential iron from their mammalian hosts, but host-defenses maintain vanishingly low levels of free iron. Although pathogens have evolved mechanisms to procure host-iron, these depend on well-regulated iron homeostasis. To disrupt iron homeostasis, our work has targeted iron mobilization from the iron storage protein bacterioferritin (BfrB) by blocking a required interaction with its cognate ferredoxin partner (Bfd). The blockade of the BfrB–Bfd complex by deletion of the bfd gene (Δbfd) causes iron to irreversibly accumulate in BfrB. In this study we used mass spectrometry and NMR spectroscopy to compare the proteomic response and the levels of key intracellular metabolites between wild type (wt) and isogenic ΔbfdP. aeruginosa strains. We find that the irreversible accumulation of unusable iron in BfrB leads to acute intracellular iron limitation, even if the culture media is iron-sufficient. Importantly, the iron limitation and concomitant iron metabolism dysregulation trigger a cascade of events that lead to broader metabolic homeostasis disruption, which includes sulfur limitation, phenazine-mediated oxidative stress, suboptimal amino acid synthesis and altered carbon metabolism.
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12
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Ganley JG, D'Ambrosio HK, Shieh M, Derbyshire ER. Coculturing of Mosquito-Microbiome Bacteria Promotes Heme Degradation in Elizabethkingia anophelis. Chembiochem 2020; 21:1279-1284. [PMID: 31845464 DOI: 10.1002/cbic.201900675] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Indexed: 12/31/2022]
Abstract
Anopheles mosquito microbiomes are intriguing ecological niches. Within the gut, microbes adapt to oxidative stress due to heme and iron after blood meals. Although metagenomic sequencing has illuminated spatial and temporal fluxes of microbiome populations, limited data exist on microbial growth dynamics. Here, we analyze growth interactions between a dominant microbiome species, Elizabethkingia anophelis, and other Anopheles-associated bacteria. We find E. anophelis inhibits a Pseudomonas sp. via an antimicrobial-independent mechanism and observe biliverdins, heme degradation products, upregulated in cocultures. Purification and characterization of E. anophelis HemS demonstrates heme degradation, and we observe hemS expression is upregulated when cocultured with Pseudomonas sp. This study reveals a competitive microbial interaction between mosquito-associated bacteria and characterizes the stimulation of heme degradation in E. anophelis when grown with Pseudomonas sp.
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Affiliation(s)
- Jack G Ganley
- Department of Chemistry, Duke University, 124 Science Drive, Durham, NC, 27708, USA
| | - Hannah K D'Ambrosio
- Department of Chemistry, Duke University, 124 Science Drive, Durham, NC, 27708, USA
| | - Meg Shieh
- Department of Chemistry, Duke University, 124 Science Drive, Durham, NC, 27708, USA
| | - Emily R Derbyshire
- Department of Chemistry, Duke University, 124 Science Drive, Durham, NC, 27708, USA.,Department of Molecular Genetics and Microbiology, Duke University Medical Center, 213 Research Drive, Durham, NC, 27710, USA
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13
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Dong J, Zhou Y, Lu Y, Lv Y, Chi Y, He Q. Effect of Tea Polyphenols on the Oxidation and Color Stability of Porcine Hemoglobin. J Food Sci 2019; 84:2086-2090. [PMID: 31294460 DOI: 10.1111/1750-3841.14703] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 05/19/2019] [Accepted: 05/21/2019] [Indexed: 01/03/2023]
Abstract
The oxidation and color stability of porcine hemoglobin (Hb) in the presence of tea polyphenols (TP), as well as the mechanism, were investigated using the methods of color and oxidation analyses, ultraviolet-visible and fluorescence spectroscopy. Results indicated that TP interacted with the tryptophan and tyrosine residues of Hb through inserting into its hydrophobic pocket. This interaction showed a concentration-dependent effect on Hb, which might lead to completely opposite results. The presence of TP (16 mg/L) disrupted Hb (16 mg/L) structure, and the exposure of heme iron facilitated the oxidation and discoloration of Hb. However, a lower level of TP should not break Hb structure but could work as an antioxidant and restrain the formation of methemoglobin. Consequently, TP (1.6 mg/L) considerably maintained the redness of Hb (16 mg/L, P < 0.05) when stored at pH 7.4 and 25 °C for 72 hr. Results may provide scientific information for the proper use of TP in blood and meat products. PRACTICAL APPLICATION: Proper utilization of tea polyphenols (TP) in food products is beneficial to improve antioxidant capacity and nutrition quality of food. We proved that it was potential to corporate TP into blood and meat products to prevent discoloration and oxidative deterioration.
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Affiliation(s)
- Jingwen Dong
- College of Light Industry and Food Engineering, Sichuan Univ., Chengdu, 610065, P. R. China
| | - Yaoqing Zhou
- College of Light Industry and Food Engineering, Sichuan Univ., Chengdu, 610065, P. R. China
| | - Yunhao Lu
- College of Light Industry and Food Engineering, Sichuan Univ., Chengdu, 610065, P. R. China
| | - Yuanping Lv
- College of Light Industry and Food Engineering, Sichuan Univ., Chengdu, 610065, P. R. China
| | - Yuanlong Chi
- College of Light Industry and Food Engineering, Sichuan Univ., Chengdu, 610065, P. R. China
| | - Qiang He
- College of Light Industry and Food Engineering, Sichuan Univ., Chengdu, 610065, P. R. China
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14
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Verstraete MM, Morales LD, Kobylarz MJ, Loutet SA, Laakso HA, Pinter TB, Stillman MJ, Heinrichs DE, Murphy MEP. The heme-sensitive regulator SbnI has a bifunctional role in staphyloferrin B production by Staphylococcus aureus. J Biol Chem 2019; 294:11622-11636. [PMID: 31197035 DOI: 10.1074/jbc.ra119.007757] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 06/12/2019] [Indexed: 01/30/2023] Open
Abstract
Staphylococcus aureus infection relies on iron acquisition from its host. S. aureus takes up iron through heme uptake by the iron-responsive surface determinant (Isd) system and by the production of iron-scavenging siderophores. Staphyloferrin B (SB) is a siderophore produced by the 9-gene sbn gene cluster for SB biosynthesis and efflux. Recently, the ninth gene product, SbnI, was determined to be a free l-serine kinase that produces O-phospho-l-serine (OPS), a substrate for SB biosynthesis. Previous studies have also characterized SbnI as a DNA-binding regulatory protein that senses heme to control sbn gene expression for SB synthesis. Here, we present crystal structures at 1.9-2.1 Å resolution of a SbnI homolog from Staphylococcus pseudintermedius (SpSbnI) in both apo form and in complex with ADP, a product of the kinase reaction; the latter confirmed the active-site location. The structures revealed that SpSbnI forms a dimer through C-terminal domain swapping and a dimer of dimers through intermolecular disulfide formation. Heme binding had only a modest effect on SbnI enzymatic activity, suggesting that its two functions are independent and structurally distinct. We identified a heme-binding site and observed catalytic heme transfer between a heme-degrading protein of the Isd system, IsdI, and SbnI. These findings support the notion that SbnI has a bifunctional role contributing precursor OPS to SB synthesis and directly sensing heme to control expression of the sbn locus. We propose that heme transfer from IsdI to SbnI enables S. aureus to control iron source preference according to the sources available in the environment.
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Affiliation(s)
- Meghan M Verstraete
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - L Daniela Morales
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Marek J Kobylarz
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Slade A Loutet
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Holly A Laakso
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Tyler B Pinter
- Department of Chemistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Martin J Stillman
- Department of Chemistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - David E Heinrichs
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Michael E P Murphy
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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15
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Donegan RK, Moore CM, Hanna DA, Reddi AR. Handling heme: The mechanisms underlying the movement of heme within and between cells. Free Radic Biol Med 2019; 133:88-100. [PMID: 30092350 PMCID: PMC6363905 DOI: 10.1016/j.freeradbiomed.2018.08.005] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 07/31/2018] [Accepted: 08/01/2018] [Indexed: 02/02/2023]
Abstract
Heme is an essential cofactor and signaling molecule required for virtually all aerobic life. However, excess heme is cytotoxic. Therefore, heme must be safely transported and trafficked from the site of synthesis in the mitochondria or uptake at the cell surface, to hemoproteins in most subcellular compartments. While heme synthesis and degradation are relatively well characterized, little is known about how heme is trafficked and transported throughout the cell. Herein, we review eukaryotic heme transport, trafficking, and mobilization, with a focus on factors that regulate bioavailable heme. We also highlight the role of gasotransmitters and small molecules in heme mobilization and bioavailability, and heme trafficking at the host-pathogen interface.
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Affiliation(s)
- Rebecca K Donegan
- School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, United States
| | - Courtney M Moore
- School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, United States
| | - David A Hanna
- School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, United States
| | - Amit R Reddi
- School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, United States; School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, United States; Parker Petit Institute for Bioengineering & Biosciences, Georgia Institute of Technology, Atlanta, GA 30332, United States.
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16
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Knippel RJ, Zackular JP, Moore JL, Celis AI, Weiss A, Washington MK, DuBois JL, Caprioli RM, Skaar EP. Heme sensing and detoxification by HatRT contributes to pathogenesis during Clostridium difficile infection. PLoS Pathog 2018; 14:e1007486. [PMID: 30576368 PMCID: PMC6303022 DOI: 10.1371/journal.ppat.1007486] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 11/27/2018] [Indexed: 02/04/2023] Open
Abstract
Clostridium difficile is a Gram-positive, spore-forming anaerobic bacterium that infects the colon, causing symptoms ranging from infectious diarrhea to fulminant colitis. In the last decade, the number of C. difficile infections has dramatically risen, making it the leading cause of reported hospital acquired infection in the United States. Bacterial toxins produced during C. difficile infection (CDI) damage host epithelial cells, releasing erythrocytes and heme into the gastrointestinal lumen. The reactive nature of heme can lead to toxicity through membrane disruption, membrane protein and lipid oxidation, and DNA damage. Here we demonstrate that C. difficile detoxifies excess heme to achieve full virulence within the gastrointestinal lumen during infection, and that this detoxification occurs through the heme-responsive expression of the heme activated transporter system (HatRT). Heme-dependent transcriptional activation of hatRT was discovered through an RNA-sequencing analysis of C. difficile grown in the presence of a sub-toxic concentration of heme. HatRT is comprised of a TetR family transcriptional regulator (hatR) and a major facilitator superfamily transporter (hatT). Strains inactivated for hatR or hatT are more sensitive to heme toxicity than wild-type. HatR binds heme, which relieves the repression of the hatRT operon, whereas HatT functions as a heme efflux pump. In a murine model of CDI, a strain inactivated for hatT displayed lower pathogenicity in a toxin-independent manner. Taken together, these data suggest that HatR senses intracellular heme concentrations leading to increased expression of the hatRT operon and subsequent heme efflux by HatT during infection. These results describe a mechanism employed by C. difficile to relieve heme toxicity within the host, and set the stage for the development of therapeutic interventions to target this bacterial-specific system.
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Affiliation(s)
- Reece J. Knippel
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States of America
- Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Joseph P. Zackular
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States of America
- Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Jessica L. Moore
- Department of Biochemistry, Vanderbilt University, Nashville, TN, United States of America
| | - Arianna I. Celis
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, United States of America
| | - Andy Weiss
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States of America
- Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - M. Kay Washington
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Jennifer L. DuBois
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, United States of America
| | - Richard M. Caprioli
- Department of Chemistry, Vanderbilt University, Nashville, TN, United States of America
| | - Eric P. Skaar
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States of America
- Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, TN, United States of America
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17
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Fiege K, Querebillo CJ, Hildebrandt P, Frankenberg-Dinkel N. Improved Method for the Incorporation of Heme Cofactors into Recombinant Proteins Using Escherichia coli Nissle 1917. Biochemistry 2018; 57:2747-2755. [DOI: 10.1021/acs.biochem.8b00242] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kerstin Fiege
- Technische Universität Kaiserslautern, Fachbereich Biologie, Abt. Mikrobiologie, Erwin-Schrödinger-Straße 56, D-67663 Kaiserslautern, Germany
| | - Christine Joy Querebillo
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Straße des 17. Juni 135, D-10623 Berlin, Germany
- School of Analytical Sciences Adlershof, Humboldt-Universität zu Berlin, Unter den Linden 6, D-10099 Berlin, Germany
| | - Peter Hildebrandt
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Nicole Frankenberg-Dinkel
- Technische Universität Kaiserslautern, Fachbereich Biologie, Abt. Mikrobiologie, Erwin-Schrödinger-Straße 56, D-67663 Kaiserslautern, Germany
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18
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Liang D, Robinson E, Hom K, Yu W, Nguyen N, Li Y, Zong Q, Wilks A, Xue F. Structure-based design and biological evaluation of inhibitors of the pseudomonas aeruginosa heme oxygenase (pa-HemO). Bioorg Med Chem Lett 2018; 28:1024-1029. [PMID: 29459206 DOI: 10.1016/j.bmcl.2018.02.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 02/03/2018] [Accepted: 02/13/2018] [Indexed: 02/03/2023]
Affiliation(s)
- Dongdong Liang
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States
| | - Elizabeth Robinson
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States
| | - Kellie Hom
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States
| | - Wenbo Yu
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States
| | - Nam Nguyen
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States
| | - Yue Li
- Department of Chemistry and Biochemistry, University of Maryland College Park, College Park 20740, United States
| | - Qianshou Zong
- College of Biological and Chemical Sciences and Engineering, Jiaxing University, Jiaxing City, Zhejiang 314001, People's Republic of China
| | - Angela Wilks
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States.
| | - Fengtian Xue
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States.
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19
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Geeraerts Z, Rodgers KR, DuBois JL, Lukat-Rodgers GS. Active Sites of O 2-Evolving Chlorite Dismutases Probed by Halides and Hydroxides and New Iron-Ligand Vibrational Correlations. Biochemistry 2017; 56:4509-4524. [PMID: 28758386 DOI: 10.1021/acs.biochem.7b00572] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
O2-evolving chlorite dismutases (Clds) fall into two subfamilies, which efficiently convert ClO2- to O2 and Cl-. The Cld from Dechloromonas aromatica (DaCld) represents the chlorite-decomposing homopentameric enzymes found in perchlorate- and chlorate-respiring bacteria. The Cld from the Gram-negative human pathogen Klebsiella pneumoniae (KpCld) is representative of the second subfamily, comprising homodimeric enzymes having truncated N-termini. Here steric and nonbonding properties of the DaCld and KpCld active sites have been probed via kinetic, thermodynamic, and spectroscopic behaviors of their fluorides, chlorides, and hydroxides. Cooperative binding of Cl- to KpCld drives formation of a hexacoordinate, high-spin aqua heme, whereas DaCld remains pentacoordinate and high-spin under analogous conditions. Fluoride coordinates to the heme iron in KpCld and DaCld, exhibiting ν(FeIII-F) bands at 385 and 390 cm-1, respectively. Correlation of these frequencies with their CT1 energies reveals strong H-bond donation to the F- ligand, indicating that atoms directly coordinated to heme iron are accessible to distal H-bond donation. New vibrational frequency correlations between either ν(FeIII-F) or ν(FeIII-OH) and ν(FeII-His) of Clds and other heme proteins are reported. These correlations orthogonalize proximal and distal effects on the bonding between iron and exogenous π-donor ligands. The axial Fe-X vibrations and the relationships between them illuminate both similarities and differences in the H-bonding and electrostatic properties of the distal and proximal heme environments in pentameric and dimeric Clds. Moreover, they provide general insight into the structural basis of reactivity toward substrates in heme-dependent enzymes and their mechanistic intermediates, especially those containing the ferryl moiety.
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Affiliation(s)
- Zachary Geeraerts
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58102, United States
| | - Kenton R Rodgers
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58102, United States
| | - Jennifer L DuBois
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, Montana 59715, United States
| | - Gudrun S Lukat-Rodgers
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58102, United States
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20
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Onzuka M, Sekine Y, Uchida T, Ishimori K, Ozaki SI. HmuS from Yersinia pseudotuberculosis is a non-canonical heme-degrading enzyme to acquire iron from heme. Biochim Biophys Acta Gen Subj 2017; 1861:1870-1878. [PMID: 28385652 DOI: 10.1016/j.bbagen.2017.04.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 03/22/2017] [Accepted: 04/02/2017] [Indexed: 01/28/2023]
Abstract
Some Gram-negative pathogens import host heme into the cytoplasm and utilize it as an iron source for their survival. We report here that HmuS, encoded by the heme utilizing system (hmu) locus, cleaves the protoporphyrin ring to release iron from heme. A liquid chromatography/mass spectrometry analysis revealed that the degradation products of this reaction are two biliverdin isomers that result from transformation of a verdoheme intermediate. This oxidative heme degradation by HmuS required molecular oxygen and electrons supplied by either ascorbate or NADPH. Electrons could not be directly transferred from NADPH to heme; instead, ferredoxin-NADP+ reductase (FNR) functioned as a mediator. Although HmuS does not share amino acid sequence homology with heme oxygenase (HO), a well-known heme-degrading enzyme, absorption and resonance Raman spectral analyses suggest that the heme iron is coordinated with an axial histidine residue and a water molecule in both enzymes. The substitution of axial His196 or distal Arg102 with an alanine residue in HmuS almost completely eliminated heme-degradation activity, suggesting that Fe-His coordination and interaction of a distal residue with water molecules in the heme pocket are important for this activity.
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Affiliation(s)
- Masato Onzuka
- Department of Biological Chemistry, Graduate School of Science and Technology for Innovation, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan
| | - Yukari Sekine
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan
| | - Takeshi Uchida
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan; Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Koichiro Ishimori
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan; Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Shin-Ichi Ozaki
- Department of Biological Chemistry, Graduate School of Science and Technology for Innovation, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan.
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21
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Ligand-induced allostery in the interaction of the Pseudomonas aeruginosa heme binding protein with heme oxygenase. Proc Natl Acad Sci U S A 2017; 114:3421-3426. [PMID: 28289188 DOI: 10.1073/pnas.1606931114] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A heme-dependent conformational rearrangement of the C-terminal domain of heme binding protein (PhuS) is required for interaction with the iron-regulated heme oxygenase (HemO). Herein, we further investigate the underlying mechanism of this conformational rearrangement and its implications for heme transfer via site-directed mutagenesis, resonance Raman (RR), hydrogen-deuterium exchange MS (HDX-MS) methods, and molecular dynamics (MD). HDX-MS revealed that the apo-PhuS C-terminal α6/α7/α8-helices are largely unstructured, whereas the apo-PhuS H212R variant showed an increase in structure within these regions. The increased rate of heme association with apo-PhuS H212R compared with the WT and lack of a detectable five-coordinate high-spin (5cHS) heme intermediate are consistent with a more folded and less dynamic C-terminal domain. HDX-MS and MD of holo-PhuS indicate an overall reduction in molecular flexibility throughout the protein, with significant structural rearrangement and protection of the heme binding pocket. We observed slow cooperative unfolding/folding events within the C-terminal helices of holo-PhuS and the N-terminal α1/α2-helices that are dampened or eliminated in the holo-PhuS H212R variant. Chemical cross-linking and MALDI-TOF MS mapped these same regions to the PhuS:HemO protein-protein interface. We previously proposed that the protein-protein interaction induces conformational rearrangement, promoting a ligand switch from His-209 to His-212 and triggering heme release to HemO. The reduced conformational freedom of holo-PhuS H212R combined with the increase in entropy and decrease in heme transfer on interaction with HemO further support this model. This study provides significant insight into the role of protein dynamics in heme binding and release in bacterial heme transport proteins.
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22
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Brewitz HH, Hagelueken G, Imhof D. Structural and functional diversity of transient heme binding to bacterial proteins. Biochim Biophys Acta Gen Subj 2017; 1861:683-697. [DOI: 10.1016/j.bbagen.2016.12.021] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 12/15/2016] [Accepted: 12/20/2016] [Indexed: 11/27/2022]
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23
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Dual-seq transcriptomics reveals the battle for iron during Pseudomonas aeruginosa acute murine pneumonia. Sci Rep 2016; 6:39172. [PMID: 27982111 PMCID: PMC5159919 DOI: 10.1038/srep39172] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 11/18/2016] [Indexed: 12/21/2022] Open
Abstract
Determining bacterial gene expression during infection is fundamental to understand pathogenesis. In this study, we used dual RNA-seq to simultaneously measure P. aeruginosa and the murine host’s gene expression and response to respiratory infection. Bacterial genes encoding products involved in metabolism and virulence were differentially expressed during infection and the type III and VI secretion systems were highly expressed in vivo. Strikingly, heme acquisition, ferric-enterobactin transport, and pyoverdine biosynthesis genes were found to be significantly up-regulated during infection. In the mouse, we profiled the acute immune response to P. aeruginosa and identified the pro-inflammatory cytokines involved in acute response to the bacterium in the lung. Additionally, we also identified numerous host iron sequestration systems upregulated during infection. Overall, this work sheds light on how P. aeruginosa triggers a pro-inflammatory response and competes for iron with the host during infection, as iron is one of the central elements for which both pathogen and host fight during acute pneumonia.
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24
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Reinhart AA, Oglesby-Sherrouse AG. Regulation of Pseudomonas aeruginosa Virulence by Distinct Iron Sources. Genes (Basel) 2016; 7:genes7120126. [PMID: 27983658 PMCID: PMC5192502 DOI: 10.3390/genes7120126] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 12/02/2016] [Accepted: 12/05/2016] [Indexed: 02/06/2023] Open
Abstract
Pseudomonas aeruginosa is a ubiquitous environmental bacterium and versatile opportunistic pathogen. Like most other organisms, P. aeruginosa requires iron for survival, yet iron rapidly reacts with oxygen and water to form stable ferric (FeIII) oxides and hydroxides, limiting its availability to living organisms. During infection, iron is also sequestered by the host innate immune system, further limiting its availability. P. aeruginosa’s capacity to cause disease in diverse host environments is due to its ability to scavenge iron from a variety of host iron sources. Work over the past two decades has further shown that different iron sources can affect the expression of distinct virulence traits. This review discusses how the individual components of P. aeruginosa’s iron regulatory network allow this opportunist to adapt to a multitude of host environments during infection.
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Affiliation(s)
- Alexandria A Reinhart
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA.
| | - Amanda G Oglesby-Sherrouse
- Department of Pharmaceutical Sciences, School of Pharmacy, and Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, MD 21201, USA.
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25
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Sigala PA, Morante K, Tsumoto K, Caaveiro JMM, Goldberg DE. In-Cell Enzymology To Probe His-Heme Ligation in Heme Oxygenase Catalysis. Biochemistry 2016; 55:4836-49. [PMID: 27490825 DOI: 10.1021/acs.biochem.6b00562] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Heme oxygenase (HO) is a ubiquitous enzyme with key roles in inflammation, cell signaling, heme disposal, and iron acquisition. HO catalyzes the oxidative conversion of heme to biliverdin (BV) using a conserved histidine to coordinate the iron atom of bound heme. This His-heme interaction has been regarded as being essential for enzyme activity, because His-to-Ala mutants fail to convert heme to biliverdin in vitro. We probed a panel of proximal His mutants of cyanobacterial, human, and plant HO enzymes using a live-cell activity assay based on heterologous co-expression in Escherichia coli of each HO mutant and a fluorescent biliverdin biosensor. In contrast to in vitro studies with purified proteins, we observed that multiple HO mutants retained significant activity within the intracellular environment of bacteria. X-ray crystallographic structures of human HO1 H25R with bound heme and additional functional studies suggest that HO mutant activity inside these cells does not involve heme ligation by a proximal amino acid. Our study reveals unexpected plasticity in the active site binding interactions with heme that can support HO activity within cells, suggests important contributions by the surrounding active site environment to HO catalysis, and can guide efforts to understand the evolution and divergence of HO function.
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Affiliation(s)
- Paul A Sigala
- Departments of Medicine and Molecular Microbiology, Washington University School of Medicine , St. Louis, Missouri 63110, United States
| | - Koldo Morante
- Department of Bioengineering, Graduate School of Engineering, The University of Tokyo , Bunkyo-ku, Tokyo 113-8654, Japan
| | - Kouhei Tsumoto
- Department of Bioengineering, Graduate School of Engineering, The University of Tokyo , Bunkyo-ku, Tokyo 113-8654, Japan.,Medical Proteomics Laboratory, Institute of Medical Science, The University of Tokyo , Minato-ku, Tokyo 108-8639, Japan
| | - Jose M M Caaveiro
- Department of Bioengineering, Graduate School of Engineering, The University of Tokyo , Bunkyo-ku, Tokyo 113-8654, Japan
| | - Daniel E Goldberg
- Departments of Medicine and Molecular Microbiology, Washington University School of Medicine , St. Louis, Missouri 63110, United States
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26
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Choby JE, Skaar EP. Heme Synthesis and Acquisition in Bacterial Pathogens. J Mol Biol 2016; 428:3408-28. [PMID: 27019298 PMCID: PMC5125930 DOI: 10.1016/j.jmb.2016.03.018] [Citation(s) in RCA: 196] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/16/2016] [Accepted: 03/17/2016] [Indexed: 02/06/2023]
Abstract
Bacterial pathogens require the iron-containing cofactor heme to cause disease. Heme is essential to the function of hemoproteins, which are involved in energy generation by the electron transport chain, detoxification of host immune effectors, and other processes. During infection, bacterial pathogens must synthesize heme or acquire heme from the host; however, host heme is sequestered in high-affinity hemoproteins. Pathogens have evolved elaborate strategies to acquire heme from host sources, particularly hemoglobin, and both heme acquisition and synthesis are important for pathogenesis. Paradoxically, excess heme is toxic to bacteria and pathogens must rely on heme detoxification strategies. Heme is a key nutrient in the struggle for survival between host and pathogen, and its study has offered significant insight into the molecular mechanisms of bacterial pathogenesis.
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Affiliation(s)
- Jacob E Choby
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA; Tennessee Valley Healthcare System, U.S. Department of Veterans Affairs, Nashville, TN, USA.
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27
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Mouriño S, Giardina BJ, Reyes-Caballero H, Wilks A. Metabolite-driven Regulation of Heme Uptake by the Biliverdin IXβ/δ-Selective Heme Oxygenase (HemO) of Pseudomonas aeruginosa. J Biol Chem 2016; 291:20503-15. [PMID: 27493207 DOI: 10.1074/jbc.m116.728527] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Indexed: 11/06/2022] Open
Abstract
Pseudomonas aeruginosa acquires extracellular heme via the Phu (Pseudomonas heme uptake) and Has (heme assimilation system) systems. We have previously shown the catalytic actions of heme oxygenase (HemO) along with the cytoplasmic heme transport protein PhuS control heme flux into the cell. To further investigate the role of the PhuS-HemO couple in modulating heme uptake, we have characterized two HemO variants, one that is catalytically inactive (HemO H26A/K34A/K132A or HemOin) and one that has altered regioselectivity (HemO N19K/K34A/F117Y/K132A or HemOα), producing biliverdin IXα (BVIXα). HemOα similar to wild type was able to interact and acquire heme from holo-PhuS. In contrast, the HemOin variant did not interact with holo-PhuS and showed no enzymatic activity. Complementation of a hemO deletion strain with the hemOin or hemOα variants in combination with [(13)C]heme isotopic labeling experiments revealed that the absence of BVIXβ and BVIXδ leads to a decrease in extracellular levels of hemophore HasA. We propose BVIXβ and/or BVIXδ transcriptionally or post-transcriptionally regulates HasA. Thus, coupling the PhuS-dependent flux of heme through HemO to feedback regulation of the cell surface signaling system through HasA allows P. aeruginosa to rapidly respond to fluctuating extracellular heme levels independent of the iron status of the cell.
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Affiliation(s)
- Susana Mouriño
- From the Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201
| | - Bennett J Giardina
- From the Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201
| | - Hermes Reyes-Caballero
- From the Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201
| | - Angela Wilks
- From the Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201
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28
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Sachla AJ, Ouattara M, Romero E, Agniswamy J, Weber IT, Gadda G, Eichenbaum Z. In vitro heme biotransformation by the HupZ enzyme from Group A streptococcus. Biometals 2016; 29:593-609. [PMID: 27154580 DOI: 10.1007/s10534-016-9937-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 05/01/2016] [Indexed: 01/14/2023]
Abstract
In Group A streptococcus (GAS), the metallorepressor MtsR regulates iron homeostasis. Here we describe a new MtsR-repressed gene, which we named hupZ (heme utilization protein). A recombinant HupZ protein was purified bound to heme from Escherichia coli grown in the presence of 5-aminolevulinic acid and iron. HupZ specifically binds heme with stoichiometry of 1:1. The addition of NADPH to heme-bound HupZ (in the presence of cytochrome P450 reductase, NADPH-regeneration system and catalase) triggered progressive decrease of the HupZ Soret band and the appearance of an absorption peak at 660 nm that was resistance to hydrolytic conditions. No spectral changes were observed when ferredoxin and ferredoxin reductase were used as redox partners. Differential spectroscopy with myoglobin or with the ferrous chelator, ferrozine, confirmed that carbon monoxide and free iron are produced during the reaction. ApoHupZ was crystallized as a homodimer with a split β-barrel conformation in each monomer comprising six β strands and three α helices. This structure resembles the split β-barrel domain shared by the members of a recently described family of heme degrading enzymes. However, HupZ is smaller and lacks key residues found in the proteins of the latter group. Phylogenetic analysis places HupZ on a clade separated from those for previously described heme oxygenases. In summary, we have identified a new GAS enzyme-containing split β-barrel and capable of heme biotransformation in vitro; to the best of our knowledge, this is the first enzyme among Streptococcus species with such activity.
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Affiliation(s)
- Ankita J Sachla
- Department of Biology, College of Arts and Sciences, Georgia State University, P.O. Box 4010, Atlanta, GA, 30302-4010, USA
| | - Mahamoudou Ouattara
- Department of Biology, College of Arts and Sciences, Georgia State University, P.O. Box 4010, Atlanta, GA, 30302-4010, USA
| | - Elvira Romero
- Department of Chemistry, College of Arts and Sciences, Georgia State University, Atlanta, GA, 30302-3965, USA
| | - Johnson Agniswamy
- Department of Biology, College of Arts and Sciences, Georgia State University, P.O. Box 4010, Atlanta, GA, 30302-4010, USA
| | - Irene T Weber
- Department of Biology, College of Arts and Sciences, Georgia State University, P.O. Box 4010, Atlanta, GA, 30302-4010, USA.,Department of Chemistry, College of Arts and Sciences, Georgia State University, Atlanta, GA, 30302-3965, USA.,Center for Biotechnology and Drug Design, Georgia State University, Atlanta, GA, 30303, USA
| | - Giovanni Gadda
- Department of Biology, College of Arts and Sciences, Georgia State University, P.O. Box 4010, Atlanta, GA, 30302-4010, USA.,Department of Chemistry, College of Arts and Sciences, Georgia State University, Atlanta, GA, 30302-3965, USA.,Center for Biotechnology and Drug Design, Georgia State University, Atlanta, GA, 30303, USA.,Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, 30303, USA
| | - Zehava Eichenbaum
- Department of Biology, College of Arts and Sciences, Georgia State University, P.O. Box 4010, Atlanta, GA, 30302-4010, USA.
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29
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Sekine Y, Tanzawa T, Tanaka Y, Ishimori K, Uchida T. Cytoplasmic Heme-Binding Protein (HutX) from Vibrio cholerae Is an Intracellular Heme Transport Protein for the Heme-Degrading Enzyme, HutZ. Biochemistry 2016; 55:884-93. [DOI: 10.1021/acs.biochem.5b01273] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yukari Sekine
- Graduate
School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0810, Japan
| | - Takehito Tanzawa
- Graduate
School of Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Yoshikazu Tanaka
- Faculty
of Advanced Life Science, Hokkaido University, Sapporo 060-0810, Japan
- PRESTO, Japan Science and Technology Agency, Sapporo 060-0810, Japan
| | - Koichiro Ishimori
- Graduate
School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0810, Japan
- Department
of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Takeshi Uchida
- Graduate
School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0810, Japan
- Department
of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
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30
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Ouellet YH, Ndiaye CT, Gagné SM, Sebilo A, Suits MD, Jubinville É, Jia Z, Ivancich A, Couture M. An alternative reaction for heme degradation catalyzed by the Escherichia coli O157:H7 ChuS protein: Release of hematinic acid, tripyrrole and Fe(III). J Inorg Biochem 2016; 154:103-13. [DOI: 10.1016/j.jinorgbio.2015.11.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 10/08/2015] [Accepted: 11/01/2015] [Indexed: 11/24/2022]
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31
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Liao H, Liu M, Cheng X, Zhu D, Wang M, Jia R, Chen S, Sun K, Yang Q, Biville F, Cheng A. The Detection of Hemin-Binding Proteins in Riemerella anatipestifer CH-1. Curr Microbiol 2015; 72:152-158. [PMID: 26542531 DOI: 10.1007/s00284-015-0932-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 09/21/2015] [Indexed: 10/22/2022]
Abstract
Riemerella anatipestifer (R. anatipestifer) is among the most prevalent duck pathogens, causing acute or chronic septicemia characterized by serositis. Riemerella anatipestifer can be grown on blood-enriched media, in vitro, which provides a hemin source essential for the sustainment of R. anatipestifer and activation of hemin-uptake systems. However, the genes associated with hemin uptake cannot be identified exclusively through genome sequence analysis. Here, we show that R. anatipestifer encodes outer-membrane hemin-binding proteins. Hemin-binding proteins were identified in the cytoplasm with apparent molecular mass of ~45/37/33/23/20/13 kDa, and outer membrane with apparent molecular mass of ~90/70/60/50/15 kDa by batch affinity chromatography and hemin-blotting assays. Our results indicate that these proteins are involved in hemin acquisition. Finally, hemin-binding assay further showed that R. anatipestifer can bind hemin and this capability is increased in iron limited medium, indicating the hemin-uptake system of R. anatipestifer was regulated by iron.
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Affiliation(s)
- Hebin Liao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, P.R. China.,Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, 46# Xinkang Road, Ya'an, Sichuan, 625014, P.R. China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, 611130, P.R. China
| | - Mafeng Liu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, P.R. China. .,Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, 46# Xinkang Road, Ya'an, Sichuan, 625014, P.R. China. .,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, 611130, P.R. China.
| | - Xingjun Cheng
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, P.R. China.,Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, 46# Xinkang Road, Ya'an, Sichuan, 625014, P.R. China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, 611130, P.R. China
| | - Dekang Zhu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, P.R. China.,Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, 46# Xinkang Road, Ya'an, Sichuan, 625014, P.R. China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, 611130, P.R. China
| | - Mingshu Wang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, P.R. China.,Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, 46# Xinkang Road, Ya'an, Sichuan, 625014, P.R. China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, 611130, P.R. China
| | - Renyong Jia
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, P.R. China.,Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, 46# Xinkang Road, Ya'an, Sichuan, 625014, P.R. China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, 611130, P.R. China
| | - Shun Chen
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, P.R. China.,Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, 46# Xinkang Road, Ya'an, Sichuan, 625014, P.R. China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, 611130, P.R. China
| | - Kunfeng Sun
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, P.R. China.,Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, 46# Xinkang Road, Ya'an, Sichuan, 625014, P.R. China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, 611130, P.R. China
| | - Qiao Yang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, P.R. China.,Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, 46# Xinkang Road, Ya'an, Sichuan, 625014, P.R. China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, 611130, P.R. China
| | - Francis Biville
- Unité des Infections Bactériennes Invasives, Département Infection et Epidémiologie, Institut Pasteur, Paris, France
| | - Anchun Cheng
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, P.R. China. .,Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, 46# Xinkang Road, Ya'an, Sichuan, 625014, P.R. China. .,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, 611130, P.R. China.
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32
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Smith AD, Wilks A. Differential contributions of the outer membrane receptors PhuR and HasR to heme acquisition in Pseudomonas aeruginosa. J Biol Chem 2015; 290:7756-66. [PMID: 25616666 DOI: 10.1074/jbc.m114.633495] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Pseudomonas aeruginosa PAO1 encodes two outer membrane receptors, PhuR (Pseudomonas heme uptake) and HasR (heme assimilation system). The HasR and PhuR receptors have distinct heme coordinating ligands and substrate specificities. HasR is encoded in an operon with a secreted hemophore, HasAp. In contrast the non-hemophore-dependent PhuR is encoded within an operon along with proteins required for heme translocation into the cytoplasm. Herein we report on the contributions of the HasR and PhuR receptors to heme uptake and utilization. Employing bacterial genetics and isotopic [(13)C]heme labeling studies we have shown both PhuR and HasR are required for optimal heme utilization. However, the unique His-Tyr-ligated PhuR plays a major role in the acquisition of heme. In contrast the HasR receptor plays a primary role in the sensing of extracellular heme and a supplementary role in heme uptake. We propose PhuR and HasR represent non-redundant heme receptors, capable of accessing heme across a wide range of physiological conditions on colonization of the host.
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Affiliation(s)
- Aaron D Smith
- From the Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201
| | - Angela Wilks
- From the Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201
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33
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The prrF-encoded small regulatory RNAs are required for iron homeostasis and virulence of Pseudomonas aeruginosa. Infect Immun 2014; 83:863-75. [PMID: 25510881 DOI: 10.1128/iai.02707-14] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that requires iron to cause infection, but it also must regulate the uptake of iron to avoid iron toxicity. The iron-responsive PrrF1 and PrrF2 small regulatory RNAs (sRNAs) are part of P. aeruginosa's iron regulatory network and affect the expression of at least 50 genes encoding iron-containing proteins. The genes encoding the PrrF1 and PrrF2 sRNAs are encoded in tandem in P. aeruginosa, allowing for the expression of a distinct, heme-responsive sRNA named PrrH that appears to regulate genes involved in heme metabolism. Using a combination of growth, mass spectrometry, and gene expression analysis, we showed that the ΔprrF1,2 mutant, which lacks expression of the PrrF and PrrH sRNAs, is defective for both iron and heme homeostasis. We also identified phuS, encoding a heme binding protein involved in heme acquisition, and vreR, encoding a previously identified regulator of P. aeruginosa virulence genes, as novel targets of prrF-mediated heme regulation. Finally, we showed that the prrF locus encoding the PrrF and PrrH sRNAs is required for P. aeruginosa virulence in a murine model of acute lung infection. Moreover, we showed that inoculation with a ΔprrF1,2 deletion mutant protects against future challenge with wild-type P. aeruginosa. Combined, these data demonstrate that the prrF-encoded sRNAs are critical regulators of P. aeruginosa virulence.
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34
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Sachla AJ, Le Breton Y, Akhter F, McIver KS, Eichenbaum Z. The crimson conundrum: heme toxicity and tolerance in GAS. Front Cell Infect Microbiol 2014; 4:159. [PMID: 25414836 PMCID: PMC4220732 DOI: 10.3389/fcimb.2014.00159] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 10/17/2014] [Indexed: 01/16/2023] Open
Abstract
The massive erythrocyte lysis caused by the Group A Streptococcus (GAS) suggests that the β-hemolytic pathogen is likely to encounter free heme during the course of infection. In this study, we investigated GAS mechanisms for heme sensing and tolerance. We compared the minimal inhibitory concentration of heme among several isolates and established that excess heme is bacteriostatic and exposure to sub-lethal concentrations of heme resulted in noticeable damage to membrane lipids and proteins. Pre-exposure of the bacteria to 0.1 μM heme shortened the extended lag period that is otherwise observed when naive cells are inoculated into heme-containing medium, implying that GAS is able to adapt. The global response to heme exposure was determined using microarray analysis revealing a significant transcriptome shift that included 79 up regulated and 84 down regulated genes. Among other changes, the induction of stress-related chaperones and proteases, including groEL/ES (8x), the stress regulators spxA2 (5x) and ctsR (3x), as well as redox active enzymes were prominent. The heme stimulon also encompassed a number of regulatory proteins and two-component systems that are important for virulence. A three-gene cluster that is homologous to the pefRCD system of the Group B Streptococcus was also induced by heme. PefR, a MarR-like regulator, specifically binds heme with stoichiometry of 1:2 and protoporphyrin IX (PPIX) with stoichiometry of 1:1, implicating it is one of the GAS mediators to heme response. In summary, here we provide evidence that heme induces a broad stress response in GAS, and that its success as a pathogen relies on mechanisms for heme sensing, detoxification, and repair.
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Affiliation(s)
- Ankita J Sachla
- Department of Biology, College of Arts and Sciences, Georgia State University Atlanta, GA, USA
| | - Yoann Le Breton
- Department of Cell Biology and Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland College Park, MD, USA
| | - Fahmina Akhter
- Department of Biology, College of Arts and Sciences, Georgia State University Atlanta, GA, USA
| | - Kevin S McIver
- Department of Cell Biology and Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland College Park, MD, USA
| | - Zehava Eichenbaum
- Department of Biology, College of Arts and Sciences, Georgia State University Atlanta, GA, USA
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35
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Lee MJ, Schep D, McLaughlin B, Kaufmann M, Jia Z. Structural Analysis and Identification of PhuS as a Heme-Degrading Enzyme from Pseudomonas aeruginosa. J Mol Biol 2014; 426:1936-46. [DOI: 10.1016/j.jmb.2014.02.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 02/13/2014] [Accepted: 02/14/2014] [Indexed: 10/25/2022]
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36
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Duong T, Park K, Kim T, Kang SW, Hahn MJ, Hwang HY, Kim KK. Structural and functional characterization of an Isd-type haem-degradation enzyme fromListeria monocytogenes. ACTA ACUST UNITED AC 2014; 70:615-26. [DOI: 10.1107/s1399004713030794] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 11/08/2013] [Indexed: 11/10/2022]
Abstract
Bacterial pathogens have evolved diverse types of efficient machinery to acquire haem, the most abundant source of iron in the human body, and degrade it for the utilization of iron. Gram-positive bacteria commonly encode IsdG-family proteins as haem-degrading monooxygenases.Listeria monocytogenesis predicted to possess an IsdG-type protein (Lmo2213), but the residues involved in haem monooxygenase activity are not well conserved and there is an extra N-terminal domain in Lmo2213. Therefore, its function and mechanism of action cannot be predicted. In this study, the crystal structure of Lmo2213 was determined at 1.75 Å resolution and its haem-binding and haem-degradation activities were confirmed. Structure-based mutational and functional assays of this protein, designated as an Isd-typeL. monocytogeneshaem-degrading enzyme (Isd-LmHde), identified that Glu71, Tyr87 and Trp129 play important roles in haem degradation and that the N-terminal domain is also critical for its haem-degrading activity. The haem-degradation product of Isd-LmHde is verified to be biliverdin, which is also known to be the degradation product of other bacterial haem oxygenases. This study, the first structural and functional report of the haem-degradation system inL. monocytogenes, sheds light on the concealed haem-utilization system in this life-threatening human pathogen.
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37
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Caza M, Kronstad JW. Shared and distinct mechanisms of iron acquisition by bacterial and fungal pathogens of humans. Front Cell Infect Microbiol 2013; 3:80. [PMID: 24312900 PMCID: PMC3832793 DOI: 10.3389/fcimb.2013.00080] [Citation(s) in RCA: 159] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2013] [Accepted: 10/30/2013] [Indexed: 12/12/2022] Open
Abstract
Iron is the most abundant transition metal in the human body and its bioavailability is stringently controlled. In particular, iron is tightly bound to host proteins such as transferrin to maintain homeostasis, to limit potential damage caused by iron toxicity under physiological conditions and to restrict access by pathogens. Therefore, iron acquisition during infection of a human host is a challenge that must be surmounted by every successful pathogenic microorganism. Iron is essential for bacterial and fungal physiological processes such as DNA replication, transcription, metabolism, and energy generation via respiration. Hence, pathogenic bacteria and fungi have developed sophisticated strategies to gain access to iron from host sources. Indeed, siderophore production and transport, iron acquisition from heme and host iron-containing proteins such as hemoglobin and transferrin, and reduction of ferric to ferrous iron with subsequent transport are all strategies found in bacterial and fungal pathogens of humans. This review focuses on a comparison of these strategies between bacterial and fungal pathogens in the context of virulence and the iron limitation that occurs in the human body as a mechanism of innate nutritional defense.
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Affiliation(s)
| | - James W. Kronstad
- The Michael Smith Laboratories, Department of Microbiology and Immunology, University of British ColumbiaVancouver, BC, Canada
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38
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Cornelis P, Dingemans J. Pseudomonas aeruginosa adapts its iron uptake strategies in function of the type of infections. Front Cell Infect Microbiol 2013; 3:75. [PMID: 24294593 PMCID: PMC3827675 DOI: 10.3389/fcimb.2013.00075] [Citation(s) in RCA: 234] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 10/22/2013] [Indexed: 11/13/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative γ-Proteobacterium which is known for its capacity to colonize various niches, including some invertebrate and vertebrate hosts, making it one of the most frequent bacteria causing opportunistic infections. P. aeruginosa is able to cause acute as well as chronic infections and it uses different colonization and virulence factors to do so. Infections range from septicemia, urinary infections, burn wound colonization, and chronic colonization of the lungs of cystic fibrosis patients. Like the vast majority of organisms, P. aeruginosa needs iron to sustain growth. P. aeruginosa utilizes different strategies to take up iron, depending on the type of infection it causes. Two siderophores are produced by this bacterium, pyoverdine and pyochelin, characterized by high and low affinities for iron respectively. P. aeruginosa is also able to utilize different siderophores from other microorganisms (siderophore piracy). It can also take up heme from hemoproteins via two different systems. Under microaerobic or anaerobic conditions, P. aeruginosa is also able to take up ferrous iron via its Feo system using redox-cycling phenazines. Depending on the type of infection, P. aeruginosa can therefore adapt by switching from one iron uptake system to another as we will describe in this short review.
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Affiliation(s)
- Pierre Cornelis
- Research Group Microbiology, Department of Bioengineering Sciences, Vrije Universiteit BrusselBrussels, Belgium
- Department Structural Biology, VIB, Vrije Universiteit BrusselBrussels, Belgium
| | - Jozef Dingemans
- Research Group Microbiology, Department of Bioengineering Sciences, Vrije Universiteit BrusselBrussels, Belgium
- Department Structural Biology, VIB, Vrije Universiteit BrusselBrussels, Belgium
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39
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Crystal structure of the Pseudomonas aeruginosa cytoplasmic heme binding protein, Apo-PhuS. J Inorg Biochem 2013; 128:131-6. [PMID: 23973453 PMCID: PMC3843485 DOI: 10.1016/j.jinorgbio.2013.07.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 07/19/2013] [Accepted: 07/21/2013] [Indexed: 01/07/2023]
Abstract
Iron is an essential element to all living organisms and is an important determinant of bacterial virulence. Bacteria have evolved specialized systems to sequester and transport iron from the environment or host. Pseudomonas aeruginosa, an opportunistic pathogen, uses two outer membrane receptor mediated systems (Phu and Has) to utilize host heme as a source of iron. PhuS is a 39 kDa soluble cytoplasmic heme binding protein which interacts and transports heme from the inner membrane heme transporter to the cytoplasm where it is degraded by heme oxygenase thus releasing iron. PhuS is unique among other cytoplasmic heme transporter proteins owing to the presence of three histidines in the heme binding pocket which can potentially serve as heme ligands. Out of the three histidine residues on the heme binding helix, His 209 is conserved among heme trafficking proteins while His 210 and His 212 are unique to PhuS. Here we report the crystal structure of PhuS at 1.98Å resolution which shows a unique heme binding pocket and oligomeric structure compared to other known cytoplasmic heme transporter and accounts for some of the unusual biochemical properties of PhuS.
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Runyen-Janecky LJ. Role and regulation of heme iron acquisition in gram-negative pathogens. Front Cell Infect Microbiol 2013; 3:55. [PMID: 24116354 PMCID: PMC3792355 DOI: 10.3389/fcimb.2013.00055] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 09/10/2013] [Indexed: 12/14/2022] Open
Abstract
Bacteria that reside in animal tissues and/or cells must acquire iron from their host. However, almost all of the host iron is sequestered in iron-containing compounds and proteins, the majority of which is found within heme molecules. Thus, likely iron sources for bacterial pathogens (and non-pathogenic symbionts) are free heme and heme-containing proteins. Furthermore, the cellular location of the bacterial within the host (intra or extracellular) influences the amount and nature of the iron containing compounds available for transport. The low level of free iron in the host, coupled with the presence of numerous different heme sources, has resulted in a wide range of high-affinity iron acquisition strategies within bacteria. However, since excess iron and heme are toxic to bacteria, expression of these acquisition systems is highly regulated. Precise expression in the correct host environment at the appropriate times enables heme iron acquisitions systems to contribute to the growth of bacterial pathogens within the host. This mini-review will highlight some of the recent findings in these areas for gram-negative pathogens.
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O’Neill MJ, Wilks A. The P. aeruginosa heme binding protein PhuS is a heme oxygenase titratable regulator of heme uptake. ACS Chem Biol 2013; 8:1794-802. [PMID: 23947366 DOI: 10.1021/cb400165b] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Pseudomonas aeruginosa heme utilization (Phu) system encodes several proteins involved in the acquisition of heme as an iron source. Once internalized, heme is degraded by the iron-regulated heme oxygenase, HemO to biliverdin (BV) IXδ and β. In vitro studies have shown holo-PhuS transfers heme to the iron-regulated HemO. This protein-protein interaction is specific for HemO as PhuS does not interact with the α-regioselective heme oxygenase, BphO. Bacterial genetics and isotopic labeling ((13)C-heme) studies confirmed extracellular heme is converted to (13)C-BVIX δ and β through the catalytic action of HemO. In an effort to further understand the role of PhuS, similar studies were performed on the P. aeruginosa PAO1 ΔphuS and ΔphuS/ΔhemO strains. In contrast to wild-type strain, the absence of PhuS results in extracellular heme uptake and degradation via the catalytic action of HemO and BphO. At low heme concentrations, loss of PhuS leads to inefficient extracellular heme uptake supported by the fact the mRNA levels of PhuR, HemO, and BphO remain elevated when compared to the wild-type PAO1. On increasing extracellular heme concentrations, the elevated levels of PhuR, HemO, and BphO allow "leaky uptake" and degradation of heme via HemO and BphO. Similarly, in the ΔphuS/ΔhemO strain, the higher heme concentrations combined with elevated levels of PhuR and BphO leads to nonspecific heme uptake and degradation by BphO. Thus we propose heme flux into the cell is driven by the catalytic action of HemO with PhuS acting as a "control valve" to regulate extracellular heme flux.
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Affiliation(s)
- Maura J. O’Neill
- The Department of Pharmaceutical
Sciences, School of
Pharmacy, University of Maryland, HSF II,
20 Penn Street, Baltimore, Maryland 21201-1140, United States
| | - Angela Wilks
- The Department of Pharmaceutical
Sciences, School of
Pharmacy, University of Maryland, HSF II,
20 Penn Street, Baltimore, Maryland 21201-1140, United States
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Abstract
The proliferative capability of many invasive pathogens is limited by the bioavailability of iron. Pathogens have thus developed strategies to obtain iron from their host organisms. In turn, host defense strategies have evolved to sequester iron from invasive pathogens. This review explores the mechanisms employed by bacterial pathogens to gain access to host iron sources, the role of iron in bacterial virulence, and iron-related genes required for the establishment or maintenance of infection. Host defenses to limit iron availability for bacterial growth during the acute-phase response and the consequences of iron overload conditions on susceptibility to bacterial infection are also examined. The evidence summarized herein demonstrates the importance of iron bioavailability in influencing the risk of infection and the ability of the host to clear the pathogen.
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Mayfield JA, Hammer ND, Kurker RC, Chen TK, Ojha S, Skaar EP, DuBois JL. The chlorite dismutase (HemQ) from Staphylococcus aureus has a redox-sensitive heme and is associated with the small colony variant phenotype. J Biol Chem 2013; 288:23488-504. [PMID: 23737523 DOI: 10.1074/jbc.m112.442335] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The chlorite dismutases (C-family proteins) are a widespread family of heme-binding proteins for which chemical and biological roles remain unclear. An association of the gene with heme biosynthesis in Gram-positive bacteria was previously demonstrated by experiments involving introduction of genes from two Gram-positive species into heme biosynthesis mutant strains of Escherichia coli, leading to the gene being renamed hemQ. To assess the gene product's biological role more directly, a Staphylococcus aureus strain with an inactivated hemQ gene was generated and shown to be a slow growing small colony variant under aerobic but not anaerobic conditions. The small colony variant phenotype is rescued by the addition of exogenous heme despite an otherwise wild type heme biosynthetic pathway. The ΔhemQ mutant accumulates coproporphyrin specifically under aerobic conditions. Although its sequence is highly similar to functional chlorite dismutases, the HemQ protein has no steady state reactivity with chlorite, very modest reactivity with H2O2 or peracetic acid, and no observable transient intermediates. HemQ's equilibrium affinity for heme is in the low micromolar range. Holo-HemQ reconstituted with heme exhibits heme lysis after <50 turnovers with peroxide and <10 turnovers with chlorite. The heme-free apoprotein aggregates or unfolds over time. IsdG-like proteins and antibiotic biosynthesis monooxygenases are close sequence and structural relatives of HemQ that use heme or porphyrin-like organic molecules as substrates. The genetic and biochemical data suggest a similar substrate role for heme or porphyrin, with possible sensor-regulator functions for the protein. HemQ heme could serve as the means by which S. aureus reversibly adopts an SCV phenotype in response to redox stress.
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Affiliation(s)
- Jeffrey A Mayfield
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
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Juárez-Verdayes MA, González-Uribe PM, Peralta H, Rodríguez-Martínez S, Jan-Roblero J, Escamilla-Hernández R, Cancino-Diaz ME, Cancino-Diaz JC. Detection of hssS, hssR, hrtA, and hrtB genes and their expression by hemin in Staphylococcus epidermidis. Can J Microbiol 2012; 58:1063-72. [DOI: 10.1139/w2012-086] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Staphylococcus aureus employs a heme sensing system (HssR–HssS) and a heme-regulated transporter efflux pump (HrtA–HrtB) to avoid the accumulation of heme, which is toxic at high concentrations. The detoxification system to heme has not been studied in Staphylococcus epidermidis . In this work, the hssR, hssS, hrtA, and hrtB genes were detected, and their expression when stimulated by hemin in S. epidermidis was explored. In silico genomic analyses exhibited that the genetic organization of the hssRS and hrtAB genes was identical in 11 Staphylococcus species analyzed, including S. epidermidis. Slight variations were found in their syntenic regions. The predicted secondary structure of HrtAB proteins from these species was almost identical to these of S. aureus. Additionally, hrtAB promoter sequences of some species were analyzed, and 1 or 2 different nucleotide substitutions were found in the downstream motif. Concentrations of hemin above 5 µmol/L inhibited S. epidermidis growth. However, S. epidermidis that was pre-exposed to a subinhibitory hemin concentration (1 µmol/L) was able to grow when inoculated into medium containing above 5 µmol/L hemin. The expression levels of hrtA and hrtB genes in S. epidermidis exhibited a significant difference when they were stimulated with hemin. Our results suggest that the HrtAB could be involved in hemin detoxification of S. epidermidis.
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Affiliation(s)
| | | | - Humberto Peralta
- Functional Genomics of Prokaryotes Program, Centro de Ciencias Genómicas, Universidad Autónoma de México, Cuernavaca, Mor. Mexico
| | | | - Janet Jan-Roblero
- Microbiology Department, Escuela Nacional de Ciencias Biológicas-IPN, Mexico City, Mexico
| | | | - Mario E. Cancino-Diaz
- Immunology Department, Escuela Nacional de Ciencias Biológicas-IPN, Mexico City, Mexico
| | - Juan C. Cancino-Diaz
- Microbiology Department, Escuela Nacional de Ciencias Biológicas-IPN, Mexico City, Mexico
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PAS domain residues and prosthetic group involved in BdlA-dependent dispersion response by Pseudomonas aeruginosa biofilms. J Bacteriol 2012; 194:5817-28. [PMID: 22923587 DOI: 10.1128/jb.00780-12] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Biofilm dispersion by Pseudomonas aeruginosa in response to environmental cues is dependent on the cytoplasmic BdlA protein harboring two sensory PAS domains and a chemoreceptor domain, TarH. The closest known and previously characterized BdlA homolog is the flavin adenine dinucleotide (FAD)-binding Aer, the redox potential sensor and aerotaxis transducer in Escherichia coli. Here, we made use of alanine replacement mutagenesis of the BdlA PAS domain residues previously demonstrated to be essential for aerotaxis in Aer to determine whether BdlA is a potential sensory protein. Five substitutions (D14A, N23A, W60A, I109A, and W182A) resulted in a null phenotype for dispersion. One protein, the BdlA protein with the G31A mutation (BdlA-G31A), transmitted a constant signal-on bias as it rendered P. aeruginosa biofilms hyperdispersive. The hyperdispersive phenotype correlated with increased interaction of BdlA-G31A with the phosphodiesterase DipA under biofilm growth conditions, resulting in increased phosphodiesterase activity and reduced biofilm biomass accumulation. We furthermore demonstrate that BdlA is a heme-binding protein. None of the BdlA protein variants analyzed led to a loss of the heme prosthetic group. The N-terminal PASa domain was identified as the heme-binding domain of BdlA, with BdlA-dependent nutrient-induced dispersion requiring the PASa domain. The findings suggest that BdlA plays a role in intracellular sensing of dispersion-inducing conditions and together with DipA forms a regulatory network that modulates an intracellular cyclic d-GMP (c-di-GMP) pool to enable dispersion.
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Liu M, Boulouis HJ, Biville F. Heme degrading protein HemS is involved in oxidative stress response of Bartonella henselae. PLoS One 2012; 7:e37630. [PMID: 22701524 PMCID: PMC3365110 DOI: 10.1371/journal.pone.0037630] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Accepted: 04/26/2012] [Indexed: 01/24/2023] Open
Abstract
Bartonellae are hemotropic bacteria, agents of emerging zoonoses. These bacteria are heme auxotroph Alphaproteobacteria which must import heme for supporting their growth, as they cannot synthesize it. Therefore, Bartonella genome encodes for a complete heme uptake system allowing the transportation of this compound across the outer membrane, the periplasm and the inner membranes. Heme has been proposed to be used as an iron source for Bartonella since these bacteria do not synthesize a complete system required for iron Fe3+uptake. Similarly to other bacteria which use heme as an iron source, Bartonellae must transport this compound into the cytoplasm and degrade it to allow the release of iron from the tetrapyrrole ring. For Bartonella, the gene cluster devoted to the synthesis of the complete heme uptake system also contains a gene encoding for a polypeptide that shares homologies with heme trafficking or degrading enzymes. Using complementation of an E. coli mutant strain impaired in heme degradation, we demonstrated that HemS from Bartonella henselae expressed in E. coli allows the release of iron from heme. Purified HemS from B. henselae binds heme and can degrade it in the presence of a suitable electron donor, ascorbate or NADPH-cytochrome P450 reductase. Knocking down the expression of HemS in B. henselae reduces its ability to face H2O2 induced oxidative stress.
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Affiliation(s)
- MaFeng Liu
- Université Paris-Est, Ecole nationale vétérinaire d'Alfort, UMR BIPAR INRA-Anses-UPEC-ENVA, Maisons-Alfort, France
- Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, Jilin University, Changchun, People's Republic of China
| | - Henri-Jean Boulouis
- Université Paris-Est, Ecole nationale vétérinaire d'Alfort, UMR BIPAR INRA-Anses-UPEC-ENVA, Maisons-Alfort, France
| | - Francis Biville
- Université Paris-Est, Ecole nationale vétérinaire d'Alfort, UMR BIPAR INRA-Anses-UPEC-ENVA, Maisons-Alfort, France
- Département de Microbiologie, Pasteur Institute, Paris, France
- * E-mail:
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Barker KD, Barkovits K, Wilks A. Metabolic flux of extracellular heme uptake in Pseudomonas aeruginosa is driven by the iron-regulated heme oxygenase (HemO). J Biol Chem 2012; 287:18342-50. [PMID: 22493498 DOI: 10.1074/jbc.m112.359265] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Heme utilization by Pseudomonas aeruginosa involves several proteins required for internalization and degradation of heme. In the following report we provide the first direct in vivo evidence for the specific degradation of extracellular heme to biliverdin (BV) by the iron-regulated HemO. Moreover, through isotopic labeling ((13)C-heme) and electrospray ionization-MS analysis we have confirmed the regioselectivity and ratio of (13)C-δ and β-BV IX (70:30) is identical in vivo to that previously observed for the purified protein. Furthermore, the (13)C-BV IXδ and BV IXβ products are effluxed from the cell by an as yet unidentified transporter. Conversion of extracellular heme to BV is dependent solely on the iron-regulated HemO as evidenced by the lack of BV production in the P. aeruginosa hemO deletion strain. Complementation of P. aeruginosa ΔhemO with a plasmid expressing either the wild type HemO or α-regioselective HemO mutant restored extracellular heme uptake and degradation. In contrast deletion of the gene encoding the cytoplasmic heme-binding protein, PhuS, homologs of which have been proposed to be heme oxygenases, did not eliminate (13)C-BV IXδ and IXβ production. In conclusion the metabolic flux of extracellular heme as a source of iron is driven by the catalytic action of HemO.
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Affiliation(s)
- Kylie D Barker
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201-1140, USA
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48
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Induced fit on heme binding to the Pseudomonas aeruginosa cytoplasmic protein (PhuS) drives interaction with heme oxygenase (HemO). Proc Natl Acad Sci U S A 2012; 109:5639-44. [PMID: 22451925 DOI: 10.1073/pnas.1121549109] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Iron, an essential nutrient with limited bioavailability, requires specialized cellular mechanisms for uptake. Although iron uptake into the cytoplasm in the form of heme has been well characterized in many bacteria, the subsequent trafficking is poorly understood. The cytoplasmic heme-binding proteins belong to a structurally related family thought to have evolved as "induced fit" ligand-binding macromolecules. One member, Pseudomonas aeruginosa cytoplasmic protein (PhuS), has previously been shown to be important for delivering heme to the iron regulated heme oxygenase (HemO). Spectroscopic investigations of the holo-PhuS complex revealed a dynamic heme environment with overlapping but distinct heme-binding sites with alternative coordinating heme ligands, His-209 or His-212. In the present work we establish a mechanism for how heme is transferred from PhuS to its partner, HemO. Using surface plasmon resonance and isothermal titration calorimetry, we have discovered that holo-PhuS, but not apo-PhuS, forms a 1:1 complex with HemO. Sedimentation velocity and limited proteolysis experiments suggest that heme binding to PhuS induces a conformational rearrangement that drives the protein interaction with HemO. Hydrodynamic analysis reveals that the holo-PhuS displays a more expanded hydrodynamic envelope compared with apo-PhuS, and we propose that this conformational change drives the interaction with HemO. We further demonstrate that replacement of His-212 by Ala disrupts the interaction of holo-PhuS with HemO; in contrast, the His-209-Ala variant can still complex with HemO, albeit more weakly. Together, the present studies reveal a mechanism that couples a heme-dependent conformational switch in PhuS to protein-protein interaction, the subsequent free energy of which drives heme release to HemO.
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Smith AD, Wilks A. Extracellular heme uptake and the challenges of bacterial cell membranes. CURRENT TOPICS IN MEMBRANES 2012; 69:359-92. [PMID: 23046657 PMCID: PMC3731948 DOI: 10.1016/b978-0-12-394390-3.00013-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In bacteria, the fine balance of maintaining adequate iron levels while preventing the deleterious effects of excess iron has led to the evolution of sophisticated cellular mechanisms to obtain, store, and regulate iron. Iron uptake provides a significant challenge given its limited bioavailability and need to be transported across the bacterial cell wall and membranes. Pathogenic bacteria have circumvented the iron-availability issue by utilizing the hosts' heme-containing proteins as a source of iron. Once internalized, iron is liberated from the porphyrin enzymatically for cellular processes within the bacterial cell. Heme, a lipophilic and toxic molecule, poses a significant challenge in terms of transport given its chemical reactivity. As such, pathogenic bacteria have evolved sophisticated membrane transporters to coordinate, sequester, and transport heme. Recent advances in the biochemical and structural characterization of the membrane-bound heme transport proteins are discussed in the context of ligand coordination, protein-protein interaction, and heme transfer.
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Affiliation(s)
- Aaron D. Smith
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, USA
| | - Angela Wilks
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, USA
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50
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Cornelis P, Wei Q, Andrews SC, Vinckx T. Iron homeostasis and management of oxidative stress response in bacteria. Metallomics 2011; 3:540-9. [PMID: 21566833 DOI: 10.1039/c1mt00022e] [Citation(s) in RCA: 188] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Iron is both an essential nutrient for the growth of microorganisms, as well as a dangerous metal due to its capacity to generate reactive oxygen species (ROS) via the Fenton reaction. For these reasons, bacteria must tightly control the uptake and storage of iron in a manner that restricts the build-up of ROS. Therefore, it is not surprising to find that the control of iron homeostasis and responses to oxidative stress are coordinated. The mechanisms concerned with these processes, and the interactions involved, are the subject of this review.
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Affiliation(s)
- Pierre Cornelis
- Microbial Interactions, Department of Molecular and Cellular Interactions, VIB and Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
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