1
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Ping FLY, Vahsen T, Brault A, Néré R, Labbé S. The flavohemoglobin Yhb1 is a new interacting partner of the heme transporter Str3. Mol Microbiol 2024; 122:29-49. [PMID: 38778742 DOI: 10.1111/mmi.15281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 05/03/2024] [Accepted: 05/10/2024] [Indexed: 05/25/2024]
Abstract
Nitric oxide (˙NO) is a free radical that induces nitrosative stress, which can jeopardize cell viability. Yeasts have evolved diverse detoxification mechanisms to effectively counteract ˙NO-mediated cytotoxicity. One mechanism relies on the flavohemoglobin Yhb1, whereas a second one requires the S-nitrosoglutathione reductase Fmd2. To investigate heme-dependent activation of Yhb1 in response to ˙NO, we use hem1Δ-derivative Schizosaccharomyces pombe strains lacking the initial enzyme in heme biosynthesis, forcing cells to assimilate heme from external sources. Under these conditions, yhb1+ mRNA levels are repressed in the presence of iron through a mechanism involving the GATA-type transcriptional repressor Fep1. In contrast, when iron levels are low, the transcription of yhb1+ is derepressed and further induced in the presence of the ˙NO donor DETANONOate. Cells lacking Yhb1 or expressing inactive forms of Yhb1 fail to grow in a hemin-dependent manner when exposed to DETANONOate. Similarly, the loss of function of the heme transporter Str3 phenocopies the effects of Yhb1 disruption by causing hypersensitivity to DETANONOate under hemin-dependent culture conditions. Coimmunoprecipitation and bimolecular fluorescence complementation assays demonstrate the interaction between Yhb1 and the heme transporter Str3. Collectively, our findings unveil a novel pathway for activating Yhb1, fortifying yeast cells against nitrosative stress.
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Affiliation(s)
- Florie Lo Ying Ping
- Département de Biochimie et de Génomique Fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Qubec, Canada
| | - Tobias Vahsen
- Département de Biochimie et de Génomique Fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Qubec, Canada
| | - Ariane Brault
- Département de Biochimie et de Génomique Fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Qubec, Canada
| | - Raphaël Néré
- Département de Biochimie et de Génomique Fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Qubec, Canada
| | - Simon Labbé
- Département de Biochimie et de Génomique Fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Qubec, Canada
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2
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Ellis-Guardiola K, Mahoney BJ, Clubb RT. NEAr Transporter (NEAT) Domains: Unique Surface Displayed Heme Chaperones That Enable Gram-Positive Bacteria to Capture Heme-Iron From Hemoglobin. Front Microbiol 2021; 11:607679. [PMID: 33488548 PMCID: PMC7815599 DOI: 10.3389/fmicb.2020.607679] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/03/2020] [Indexed: 11/13/2022] Open
Abstract
Iron is an important micronutrient that is required by bacteria to proliferate and to cause disease. Many bacterial pathogens forage iron from human hemoglobin (Hb) during infections, which contains this metal within heme (iron-protoporphyrin IX). Several clinically important pathogenic species within the Firmicutes phylum scavenge heme using surface-displayed or secreted NEAr Transporter (NEAT) domains. In this review, we discuss how these versatile proteins function in the Staphylococcus aureus Iron-regulated surface determinant system that scavenges heme-iron from Hb. S. aureus NEAT domains function as either Hb receptors or as heme-binding chaperones. In vitro studies have shown that heme-binding NEAT domains can rapidly exchange heme amongst one another via transiently forming transfer complexes, leading to the interesting hypothesis that they may form a protein-wire within the peptidoglycan layer through which heme flows from the microbial surface to the membrane. In Hb receptors, recent studies have revealed how dedicated heme- and Hb-binding NEAT domains function synergistically to extract Hb's heme molecules, and how receptor binding to the Hb-haptoglobin complex may block its clearance by macrophages, prolonging microbial access to Hb's iron. The functions of NEAT domains in other Gram-positive bacteria are also reviewed.
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Affiliation(s)
- Ken Ellis-Guardiola
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, United States
- UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, Los Angeles, CA, United States
| | - Brendan J. Mahoney
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, United States
- UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, Los Angeles, CA, United States
| | - Robert T. Clubb
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, United States
- UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, Los Angeles, CA, United States
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, United States
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3
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Verplaetse E, André-Leroux G, Duhutrel P, Coeuret G, Chaillou S, Nielsen-Leroux C, Champomier-Vergès MC. Heme Uptake in Lactobacillus sakei Evidenced by a New Energy Coupling Factor (ECF)-Like Transport System. Appl Environ Microbiol 2020; 86:e02847-19. [PMID: 32680867 PMCID: PMC7480364 DOI: 10.1128/aem.02847-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 07/05/2020] [Indexed: 12/27/2022] Open
Abstract
Lactobacillus sakei is a nonpathogenic lactic acid bacterium and a natural inhabitant of meat ecosystems. Although red meat is a heme-rich environment, L. sakei does not need iron or heme for growth, although it possesses a heme-dependent catalase. Iron incorporation into L. sakei from myoglobin and hemoglobin was previously shown by microscopy and the L. sakei genome reveals the complete equipment for iron and heme transport. Here, we report the characterization of a five-gene cluster (from lsa1836 to lsa1840 [lsa1836-1840]) encoding a putative metal iron ABC transporter. Interestingly, this cluster, together with a heme-dependent catalase gene, is also conserved in other species from the meat ecosystem. Our bioinformatic analyses revealed that the locus might correspond to a complete machinery of an energy coupling factor (ECF) transport system. We quantified in vitro the intracellular heme in the wild type (WT) and in our Δlsa1836-1840 deletion mutant using an intracellular heme sensor and inductively coupled plasma mass spectrometry for quantifying incorporated 57Fe heme. We showed that in the WT L. sakei, heme accumulation occurs rapidly and massively in the presence of hemin, while the deletion mutant was impaired in heme uptake; this ability was restored by in trans complementation. Our results establish the main role of the L. sakei Lsa1836-1840 ECF-like system in heme uptake. Therefore, this research outcome sheds new light on other possible functions of ECF-like systems.IMPORTANCELactobacillus sakei is a nonpathogenic bacterial species exhibiting high fitness in heme-rich environments such as meat products, although it does not need iron or heme for growth. Heme capture and utilization capacities are often associated with pathogenic species and are considered virulence-associated factors in the infected hosts. For these reasons, iron acquisition systems have been deeply studied in such species, while for nonpathogenic bacteria the information is scarce. Genomic data revealed that several putative iron transporters are present in the genome of the lactic acid bacterium L. sakei In this study, we demonstrate that one of them is an ECF-like ABC transporter with a functional role in heme transport. Such evidence has not yet been brought for an ECF; therefore, our study reveals a new class of heme transport system.
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Affiliation(s)
- Emilie Verplaetse
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | | | - Philippe Duhutrel
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Gwendoline Coeuret
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Stéphane Chaillou
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
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4
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Progress towards the Development of a NEAT Vaccine for Anthrax II: Immunogen Specificity and Alum Effectiveness in an Inhalational Model. Infect Immun 2020; 88:IAI.00082-20. [PMID: 32393506 DOI: 10.1128/iai.00082-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 04/23/2020] [Indexed: 12/24/2022] Open
Abstract
Bacillus anthracis is the causative agent of anthrax disease, presents with high mortality, and has been at the center of bioweapon efforts. The only currently U.S. FDA-approved vaccine to prevent anthrax in humans is anthrax vaccine adsorbed (AVA), which is protective in several animal models and induces neutralizing antibodies against protective antigen (PA), the cell-binding component of anthrax toxin. However, AVA requires a five-course regimen to induce immunity, along with an annual booster, and is composed of undefined culture supernatants from a PA-secreting strain. In addition, it appears to be ineffective against strains that lack anthrax toxin. Here, we investigated a vaccine formulation consisting of recombinant proteins from a surface-localized heme transport system containing near-iron transporter (NEAT) domains and its efficacy as a vaccine for anthrax disease. The cocktail of five NEAT domains was protective against a lethal challenge of inhaled bacillus spores at 3 and 28 weeks after vaccination. The reduction of the formulation to three NEATs (IsdX1, IsdX2, and Bslk) was as effective as a five-NEAT domain cocktail. The adjuvant alum, approved for use in humans, was as protective as Freund's Adjuvant, and protective vaccination correlated with increased anti-NEAT antibody reactivity and reduced bacterial levels in organs. Finally, the passive transfer of anti-NEAT antisera reduced mortality and disease severity, suggesting the protective component is comprised of antibodies. Collectively, these results provide evidence that a vaccine based upon recombinant NEAT proteins should be considered in the development of a next-generation anthrax vaccine.
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5
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Machinery for fungal heme acquisition. Curr Genet 2020; 66:703-711. [PMID: 32185489 DOI: 10.1007/s00294-020-01067-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 03/04/2020] [Accepted: 03/05/2020] [Indexed: 02/07/2023]
Abstract
Iron is essential for nearly all aerobic organisms. One source of iron in nature is in the form of heme. Due to its critical physiological importance as a cofactor for several enzymes, organisms have evolved various means to secure heme for their needs. In the case of heme prototrophs, these organisms possess a highly conserved eight-step biosynthetic pathway. Another means used by many organisms is to acquire heme from external sources. As opposed to the knowledge of enzymes responsible for heme biosynthesis, the nature of the players and mechanisms involved in the acquisition of exogenous heme is limited. This review focuses on a description of newly discovered proteins that have novel functions in heme assimilation in the model organism Schizosaccharomyces pombe. This tractable model allows the use of the power of genetics to selectively block heme biosynthesis, setting conditions to investigate the mechanisms by which external heme is taken up by the cells. Studies have revealed that S. pombe possesses two independent heme uptake systems that require Shu1 and Str3, respectively. Heme-bound iron is captured by Shu1 at the cell surface, triggering its internalization to the vacuole with the aid of ubiquitinated proteins and the ESCRT machinery. In the case of the plasma membrane transporter Str3, it promotes cellular heme import in cells lacking Shu1. The discovery of these two pathways may contribute to gain novel insights into the mechanisms whereby fungi assimilate heme, which is an essentially biological process for their ability to invade and colonize new niches.
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6
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Garber AI, Nealson KH, Okamoto A, McAllister SM, Chan CS, Barco RA, Merino N. FeGenie: A Comprehensive Tool for the Identification of Iron Genes and Iron Gene Neighborhoods in Genome and Metagenome Assemblies. Front Microbiol 2020; 11:37. [PMID: 32082281 PMCID: PMC7005843 DOI: 10.3389/fmicb.2020.00037] [Citation(s) in RCA: 162] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 01/09/2020] [Indexed: 01/15/2023] Open
Abstract
Iron is a micronutrient for nearly all life on Earth. It can be used as an electron donor and electron acceptor by iron-oxidizing and iron-reducing microorganisms and is used in a variety of biological processes, including photosynthesis and respiration. While it is the fourth most abundant metal in the Earth's crust, iron is often limiting for growth in oxic environments because it is readily oxidized and precipitated. Much of our understanding of how microorganisms compete for and utilize iron is based on laboratory experiments. However, the advent of next-generation sequencing and surge in publicly available sequence data has made it possible to probe the structure and function of microbial communities in the environment. To bridge the gap between our understanding of iron acquisition, iron redox cycling, iron storage, and magnetosome formation in model microorganisms and the plethora of sequence data available from environmental studies, we have created a comprehensive database of hidden Markov models (HMMs) based on genes related to iron acquisition, storage, and reduction/oxidation in Bacteria and Archaea. Along with this database, we present FeGenie, a bioinformatics tool that accepts genome and metagenome assemblies as input and uses our comprehensive HMM database to annotate provided datasets with respect to iron-related genes and gene neighborhood. An important contribution of this tool is the efficient identification of genes involved in iron oxidation and dissimilatory iron reduction, which have been largely overlooked by standard annotation pipelines. We validated FeGenie against a selected set of 28 isolate genomes and showcase its utility in exploring iron genes present in 27 metagenomes, 4 isolate genomes from human oral biofilms, and 17 genomes from candidate organisms, including members of the candidate phyla radiation. We show that FeGenie accurately identifies iron genes in isolates. Furthermore, analysis of metagenomes using FeGenie demonstrates that the iron gene repertoire and abundance of each environment is correlated with iron richness. While this tool will not replace the reliability of culture-dependent analyses of microbial physiology, it provides reliable predictions derived from the most up-to-date genetic markers. FeGenie's database will be maintained and continually updated as new genes are discovered. FeGenie is freely available: https://github.com/Arkadiy-Garber/FeGenie.
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Affiliation(s)
- Arkadiy I. Garber
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
- Department of Earth Sciences, University of Delaware, Newark, DE, United States
| | - Kenneth H. Nealson
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Akihiro Okamoto
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Sean M. McAllister
- School of Marine Science and Policy, University of Delaware, Newark, DE, United States
| | - Clara S. Chan
- Department of Earth Sciences, University of Delaware, Newark, DE, United States
- School of Marine Science and Policy, University of Delaware, Newark, DE, United States
| | - Roman A. Barco
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Nancy Merino
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, United States
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7
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Gianquinto E, Moscetti I, De Bei O, Campanini B, Marchetti M, Luque FJ, Cannistraro S, Ronda L, Bizzarri AR, Spyrakis F, Bettati S. Interaction of human hemoglobin and semi-hemoglobins with the Staphylococcus aureus hemophore IsdB: a kinetic and mechanistic insight. Sci Rep 2019; 9:18629. [PMID: 31819099 PMCID: PMC6901573 DOI: 10.1038/s41598-019-54970-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 11/21/2019] [Indexed: 12/21/2022] Open
Abstract
Among multidrug-resistant bacteria, methicillin-resistant Staphylococcus aureus is emerging as one of the most threatening pathogens. S. aureus exploits different mechanisms for its iron supply, but the preferred one is acquisition of organic iron through the expression of hemoglobin (Hb) receptors. One of these, IsdB, belonging to the Isd (Iron-Regulated Surface Determinant) system, was shown to be essential for bacterial growth and virulence. Therefore, interaction of IsdB with Hb represents a promising target for the rational design of a new class of antibacterial molecules. However, despite recent investigations, many structural and mechanistic details of complex formation and heme extraction process are still elusive. By combining site-directed mutagenesis, absorption spectroscopy, surface plasmon resonance and molecular dynamics simulations, we tackled most of the so far unanswered questions: (i) the exact complex stoichiometry, (ii) the microscopic kinetic rates of complex formation, (iii) the IsdB selectivity for binding to, and extracting heme from, α and β subunits of Hb, iv) the role of specific amino acid residues and structural regions in driving complex formation and heme transfer, and (v) the structural/dynamic effect played by the hemophore on Hb.
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Affiliation(s)
- Eleonora Gianquinto
- Department of Drug Science and Technology, University of Turin, Turin, 10125, Italy
| | - Ilaria Moscetti
- Department of Environmental and Biological Sciences, University of Tuscia, Viterbo, 01100, Italy
| | - Omar De Bei
- Department of Food and Drug, University of Parma, Parma, 43124, Italy
| | - Barbara Campanini
- Department of Food and Drug, University of Parma, Parma, 43124, Italy.,Interdepartment Center Biopharmanet-TEC, University of Parma, Parma, 43124, Italy
| | - Marialaura Marchetti
- Department of Drug Science and Technology, University of Turin, Turin, 10125, Italy.,Interdepartment Center Biopharmanet-TEC, University of Parma, Parma, 43124, Italy
| | - F Javier Luque
- Department of Nutrition, Food Science and Gastronomy, Faculty of Pharmacy and Food Sciences, Institute of Biomedicine (IBUB) and Institute of Theoretical and Computational Chemistry (IQTCUB), University of Barcelona, Santa Coloma de Gramenet, 08921, Spain
| | - Salvatore Cannistraro
- Department of Environmental and Biological Sciences, University of Tuscia, Viterbo, 01100, Italy
| | - Luca Ronda
- Interdepartment Center Biopharmanet-TEC, University of Parma, Parma, 43124, Italy.,Department of Medicine and Surgery, University of Parma, Parma, 43126, Italy.,Institute of Biophysics, National Research Council, Pisa, 56124, Italy
| | - Anna Rita Bizzarri
- Department of Environmental and Biological Sciences, University of Tuscia, Viterbo, 01100, Italy.
| | - Francesca Spyrakis
- Department of Drug Science and Technology, University of Turin, Turin, 10125, Italy.
| | - Stefano Bettati
- Interdepartment Center Biopharmanet-TEC, University of Parma, Parma, 43124, Italy. .,Department of Medicine and Surgery, University of Parma, Parma, 43126, Italy. .,Institute of Biophysics, National Research Council, Pisa, 56124, Italy.
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8
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Bennett MR, Dong J, Bombardi RG, Soto C, Parrington HM, Nargi RS, Schoeder CT, Nagel MB, Schey KL, Meiler J, Skaar EP, Crowe JE. Human VH1-69 Gene-Encoded Human Monoclonal Antibodies against Staphylococcus aureus IsdB Use at Least Three Distinct Modes of Binding To Inhibit Bacterial Growth and Pathogenesis. mBio 2019; 10:e02473-19. [PMID: 31641091 PMCID: PMC6805997 DOI: 10.1128/mbio.02473-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 09/18/2019] [Indexed: 12/30/2022] Open
Abstract
Staphylococcus aureus is an important human pathogen that infects nearly every human tissue. Like most organisms, the acquisition of nutrient iron is necessary for its survival. One route by which it obtains this metal is through the iron-regulated surface determinant (Isd) system that scavenges iron from the hemoglobin of the host. We show that the heavy chain variable region IGHV1-69 gene commonly encodes human monoclonal antibodies (mAbs) targeting IsdB-NEAT2. Remarkably, these antibodies bind to multiple antigenic sites. One class of IGHV1-69-encoded mAbs blocks S. aureus heme acquisition by binding to the heme-binding site of NEAT2, while two additional classes reduce the bacterial burden in vivo by an alternative Fc receptor-mediated mechanism. We further identified clonal lineages of IGHV1-69-encoded mAbs using donor samples, showing that each lineage diversifies during infection by somatic hypermutation. These studies reveal that IGHV1-69-encoded antibodies contribute to a protective immune response, furthering our understanding of the correlates of protection against S. aureus infection.IMPORTANCE The human pathogen Staphylococcus aureus causes a wide range of infections, including skin abscesses and sepsis. There is currently no licensed vaccine to prevent S. aureus infection, and its treatment has become increasingly difficult due to antibiotic resistance. One potential way to inhibit S. aureus pathogenesis is to prevent iron acquisition. The iron-regulated surface determinant (Isd) system has evolved in S. aureus to acquire hemoglobin from the human host as a source of heme-iron. In this study, we investigated the molecular and structural basis for antibody-mediated correlates against a member of the Isd system, IsdB. The association of immunoglobulin heavy chain variable region IGHV1-69 gene-encoded human monoclonal antibodies with the response against S. aureus IsdB is described using structural and functional studies to define the importance of this antibody class. We also determine that somatic hypermutation in the development of these antibodies hinders rather than fine-tunes the immune response to IsdB.
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Affiliation(s)
- Monique R Bennett
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Jinhui Dong
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Robin G Bombardi
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Cinque Soto
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Helen M Parrington
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Rachel S Nargi
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Clara T Schoeder
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Marcus B Nagel
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Kevin L Schey
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Jens Meiler
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - James E Crowe
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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9
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Macdonald R, Mahoney BJ, Ellis-Guardiola K, Maresso A, Clubb RT. NMR experiments redefine the hemoglobin binding properties of bacterial NEAr-iron Transporter domains. Protein Sci 2019; 28:1513-1523. [PMID: 31120610 DOI: 10.1002/pro.3662] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 05/14/2019] [Indexed: 01/02/2023]
Abstract
Iron is a versatile metal cofactor that is used in a wide range of essential cellular processes. During infections, many bacterial pathogens acquire iron from human hemoglobin (Hb), which contains the majority of the body's total iron content in the form of heme (iron protoporphyrin IX). Clinically important Gram-positive bacterial pathogens scavenge heme using an array of secreted and cell-wall-associated receptors that contain NEAr-iron Transporter (NEAT) domains. Experimentally defining the Hb binding properties of NEAT domains has been challenging, limiting our understanding of their function in heme uptake. Here we show that solution-state NMR spectroscopy is a powerful tool to define the Hb binding properties of NEAT domains. The utility of this method is demonstrated using the NEAT domains from Bacillus anthracis and Listeria monocytogenes. Our results are compatible with the existence of at least two types of NEAT domains that are capable of interacting with either Hb or heme. These binding properties can be predicted from their primary sequences, with Hb- and heme-binding NEAT domains being distinguished by the presence of (F/Y)YH(Y/F) and S/YXXXY motifs, respectively. The results of this work should enable the functions of a wide range of NEAT domain containing proteins in pathogenic bacteria to be reliably predicted.
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Affiliation(s)
- Ramsay Macdonald
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, 90095.,UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, Los Angeles, California, 90095
| | - Brendan J Mahoney
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, 90095.,UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, Los Angeles, California, 90095
| | - Ken Ellis-Guardiola
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, 90095.,UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, Los Angeles, California, 90095
| | - Anthony Maresso
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, 77030
| | - Robert T Clubb
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, 90095.,UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, Los Angeles, California, 90095.,Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California, 90095
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10
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Chao A, Sieminski PJ, Owens CP, Goulding CW. Iron Acquisition in Mycobacterium tuberculosis. Chem Rev 2018; 119:1193-1220. [PMID: 30474981 DOI: 10.1021/acs.chemrev.8b00285] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The highly contagious disease tuberculosis (TB) is caused by the bacterium Mycobacterium tuberculosis (Mtb), which has been evolving drug resistance at an alarming rate. Like all human pathogens, Mtb requires iron for growth and virulence. Consequently, Mtb iron transport is an emerging drug target. However, the development of anti-TB drugs aimed at these metabolic pathways has been restricted by the dearth of information on Mtb iron acquisition. In this Review, we describe the multiple strategies utilized by Mtb to acquire ferric iron and heme iron. Mtb iron uptake is a complex process, requiring biosynthesis and subsequent export of Mtb siderophores, followed by ferric iron scavenging and ferric-siderophore import into Mtb. Additionally, Mtb possesses two possible heme uptake pathways and an Mtb-specific mechanism of heme degradation that yields iron and novel heme-degradation products. We conclude with perspectives for potential therapeutics that could directly target Mtb heme and iron uptake machineries. We also highlight how hijacking Mtb heme and iron acquisition pathways for drug import may facilitate drug transport through the notoriously impregnable Mtb cell wall.
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Affiliation(s)
| | | | - Cedric P Owens
- Schmid College of Science and Technology , Chapman University , Orange , California 92866 , United States
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11
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Normant V, Mourer T, Labbé S. The major facilitator transporter Str3 is required for low-affinity heme acquisition in Schizosaccharomyces pombe. J Biol Chem 2018; 293:6349-6362. [PMID: 29549126 DOI: 10.1074/jbc.ra118.002132] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 03/14/2018] [Indexed: 01/03/2023] Open
Abstract
In the fission yeast Schizosaccharomyces pombe, acquisition of exogenous heme is largely mediated by the cell membrane-associated Shu1. Here, we report that Str3, a member of the major facilitator superfamily of transporters, promotes cellular heme import. Using a strain that cannot synthesize heme de novo (hem1Δ) and lacks Shu1, we found that the heme-dependent growth deficit of this strain is rescued by hemin supplementation in the presence of Str3. Microscopic analyses of a hem1Δ shu1Δ str3Δ mutant strain in the presence of the heme analog zinc mesoporphyrin IX (ZnMP) revealed that ZnMP fails to accumulate within the mutant cells. In contrast, Str3-expressing hem1Δ shu1Δ cells could take up ZnMP at a 10-μm concentration. The yeast Saccharomyces cerevisiae cannot efficiently transport exogenously supplied hemin. However, heterologous expression of Str3 from S. pombe in S. cerevisiae resulted in ZnMP accumulation within S. cerevisiae cells. Moreover, hemin-agarose pulldown assays revealed that Str3 binds hemin. In contrast, an Str3 mutant in which Tyr and Ser residues of two putative heme-binding motifs (530YX3Y534 and 552SX4Y557) had been replaced with alanines exhibited a loss of affinity for hemin. Furthermore, this Str3 mutant failed to rescue the heme-dependent growth deficit of a hem1Δ shu1Δ str3Δ strain. Further analysis by absorbance spectroscopy disclosed that a predicted extracellular loop region in Str3 containing the two putative heme-binding motifs interacts with hemin, with a KD of 6.6 μm Taken together, these results indicate that Str3 is a second cell-surface membrane protein for acquisition of exogenous heme in S. pombe.
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Affiliation(s)
- Vincent Normant
- From the Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec J1E 4K8, Canada
| | - Thierry Mourer
- From the Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec J1E 4K8, Canada
| | - Simon Labbé
- From the Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec J1E 4K8, Canada
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Nucleotide Polymorphism in the Iron Utilization System Gene isdB NEAT Domain Affects Heme-Binding Ability of IsdB Protein in Various Human Strains of Staphylococcus aureus. BIONANOSCIENCE 2018. [DOI: 10.1007/s12668-018-0501-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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13
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Abstract
Iron is an essential micronutrient for both microbes and humans alike. For well over half a century we have known that this element, in particular, plays a pivotal role in health and disease and, most especially, in shaping host-pathogen interactions. Intracellular iron concentrations serve as a critical signal in regulating the expression not only of high-affinity iron acquisition systems in bacteria, but also of toxins and other noted virulence factors produced by some major human pathogens. While we now are aware of many strategies that the host has devised to sequester iron from invading microbes, there are as many if not more sophisticated mechanisms by which successful pathogens overcome nutritional immunity imposed by the host. This review discusses some of the essential components of iron sequestration and scavenging mechanisms of the host, as well as representative Gram-negative and Gram-positive pathogens, and highlights recent advances in the field. Last, we address how the iron acquisition strategies of pathogenic bacteria may be exploited for the development of novel prophylactics or antimicrobials.
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14
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Uluisik RC, Akbas N, Lukat-Rodgers GS, Adrian SA, Allen CE, Schmitt MP, Rodgers KR, Dixon DW. Characterization of the second conserved domain in the heme uptake protein HtaA from Corynebacterium diphtheriae. J Inorg Biochem 2017; 167:124-133. [PMID: 27974280 PMCID: PMC5199035 DOI: 10.1016/j.jinorgbio.2016.11.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 10/19/2016] [Accepted: 11/22/2016] [Indexed: 11/20/2022]
Abstract
HtaA is a heme-binding protein that is part of the heme uptake system in Corynebacterium diphtheriae. HtaA contains two conserved regions (CR1 and CR2). It has been previously reported that both domains can bind heme; the CR2 domain binds hemoglobin more strongly than the CR1 domain. In this study, we report the biophysical characteristics of HtaA-CR2. UV-visible spectroscopy and resonance Raman experiments are consistent with this domain containing a single heme that is bound to the protein through an axial tyrosine ligand. Mutants of conserved tyrosine and histidine residues (Y361, H412, and Y490) have been studied. These mutants are isolated with very little heme (≤5%) in comparison to the wild-type protein (~20%). Reconstitution after removal of the heme with butanone gave an alternative form of the protein. The HtaA-CR2 fold is very stable; it was necessary to perform thermal denaturation experiments in the presence of guanidinium hydrochloride. HtaA-CR2 unfolds extremely slowly; even in 6.8M GdnHCl at 37°C, the half-life was 5h. In contrast, the apo forms of WT HtaA-CR2 and the aforementioned mutants unfolded at much lower concentrations of GdnHCl, indicating the role of heme in stabilizing the structure and implying that heme transfer is effected only to a partner protein in vivo.
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Affiliation(s)
- Rizvan C Uluisik
- Department of Chemistry, Georgia State University, Atlanta, GA 30302-3965, United States
| | - Neval Akbas
- Department of Chemistry, Georgia State University, Atlanta, GA 30302-3965, United States
| | - Gudrun S Lukat-Rodgers
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND 58108-6050, United States
| | - Seth A Adrian
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND 58108-6050, United States
| | - Courtni E Allen
- Laboratory of Respiratory and Special Pathogens, Division of Bacterial, Parasitic, and Allergenic Products, Center for Biologics Evaluation, and Research, Food and Drug Administration, Silver Spring, MD 20993, United States
| | - Michael P Schmitt
- Laboratory of Respiratory and Special Pathogens, Division of Bacterial, Parasitic, and Allergenic Products, Center for Biologics Evaluation, and Research, Food and Drug Administration, Silver Spring, MD 20993, United States
| | - Kenton R Rodgers
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND 58108-6050, United States.
| | - Dabney W Dixon
- Department of Chemistry, Georgia State University, Atlanta, GA 30302-3965, United States.
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15
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Progress toward the Development of a NEAT Protein Vaccine for Anthrax Disease. Infect Immun 2016; 84:3408-3422. [PMID: 27647868 DOI: 10.1128/iai.00755-16] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 09/10/2016] [Indexed: 01/05/2023] Open
Abstract
Bacillus anthracis is a sporulating Gram-positive bacterium that is the causative agent of anthrax and a potential weapon of bioterrorism. The U.S.-licensed anthrax vaccine is made from an incompletely characterized culture supernatant of a nonencapsulated, toxigenic strain (anthrax vaccine absorbed [AVA]) whose primary protective component is thought to be protective antigen (PA). AVA is effective in protecting animals and elicits toxin-neutralizing antibodies in humans, but enthusiasm is dampened by its undefined composition, multishot regimen, recommended boosters, and potential for adverse reactions. Improving next-generation anthrax vaccines is important to safeguard citizens and the military. Here, we report that vaccination with recombinant forms of a conserved domain (near-iron transporter [NEAT]), common in Gram-positive pathogens, elicits protection in a murine model of B. anthracis infection. Protection was observed with both Freund's and alum adjuvants, given subcutaneously and intramuscularly, respectively, with a mixed composite of NEATs. Protection correlated with an antibody response against the NEAT domains and a decrease in the numbers of bacteria in major organs. Anti-NEAT antibodies promote opsonophagocytosis of bacilli by alveolar macrophages. To guide the development of inactive and safe NEAT antigens, we also report the crystal structure of one of the NEAT domains (Hal) and identify critical residues mediating its heme-binding and acquisition activity. These results indicate that we should consider NEAT proteins in the development of an improved antianthrax vaccine.
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16
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Germline-encoded neutralization of a Staphylococcus aureus virulence factor by the human antibody repertoire. Nat Commun 2016; 7:13376. [PMID: 27857134 PMCID: PMC5120205 DOI: 10.1038/ncomms13376] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 09/28/2016] [Indexed: 11/08/2022] Open
Abstract
Staphylococcus aureus is both an important pathogen and a human commensal. To explore this ambivalent relationship between host and microbe, we analysed the memory humoral response against IsdB, a protein involved in iron acquisition, in four healthy donors. Here we show that in all donors a heavily biased use of two immunoglobulin heavy chain germlines generated high affinity (pM) antibodies that neutralize the two IsdB NEAT domains, IGHV4-39 for NEAT1 and IGHV1-69 for NEAT2. In contrast to the typical antibody/antigen interactions, the binding is primarily driven by the germline-encoded hydrophobic CDRH-2 motifs of IGHV1-69 and IGHV4-39, with a binding mechanism nearly identical for each antibody derived from different donors. Our results suggest that IGHV1-69 and IGHV4-39, while part of the adaptive immune system, may have evolved under selection pressure to encode a binding motif innately capable of recognizing and neutralizing a structurally conserved protein domain involved in pathogen iron acquisition.
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18
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Abstract
Ancient bacteria originated from metal-rich environments. Billions of years of evolution directed these tiny single cell creatures to exploit the versatile properties of metals in catalyzing chemical reactions and biological responses. The result is an entire metallome of proteins that use metal co-factors to facilitate key cellular process that range from the production of energy to the replication of DNA. Two key metals in this regard are iron and zinc, both abundant on Earth but not readily accessible in a human host. Instead, pathogenic bacteria must employ clever ways to acquire these metals. In this review we describe the many elegant ways these bacteria mine, regulate, and craft the use of two key metals (iron and zinc) to build a virulence arsenal that challenges even the most sophisticated immune response.
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Affiliation(s)
- Li Ma
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77459, USA.
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Bennett EH, Akbas N, Adrian SA, Lukat-Rodgers GS, Collins DP, Dawson JH, Allen CE, Schmitt MP, Rodgers KR, Dixon DW. Heme Binding by Corynebacterium diphtheriae HmuT: Function and Heme Environment. Biochemistry 2015; 54:6598-609. [PMID: 26478504 PMCID: PMC4943319 DOI: 10.1021/acs.biochem.5b00666] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The heme uptake pathway (hmu) of Corynebacterium diphtheriae utilizes multiple proteins to bind and transport heme into the cell. One of these proteins, HmuT, delivers heme to the ABC transporter HmuUV. In this study, the axial ligation of the heme in ferric HmuT is probed by examination of wild-type (WT) HmuT and a series of conserved heme pocket residue mutants, H136A, Y235A, and M292A. Characterization by UV-visible, resonance Raman, and magnetic circular dichroism spectroscopies indicates that H136 and Y235 are the axial ligands in ferric HmuT. Consistent with this assignment of axial ligands, ferric WT and H136A HmuT are difficult to reduce while Y235A is reduced readily in the presence of dithionite. The FeCO Raman shifts in WT, H136A, and Y235A HmuT-CO complexes provide further evidence of the axial ligand assignments. Additionally, these frequencies provide insight into the nonbonding environment of the heme pocket. Ferrous Y235A and the Y235A-CO complex reveal that the imidazole of H136 exists in two forms, one neutral and one with imidazolate character, consistent with a hydrogen bond acceptor on the H136 side of the heme. The ferric fluoride complex of Y235A reveals the presence of at least one hydrogen bond donor on the Y235 side of the heme. Hemoglobin utilization assays showed that the axial Y235 ligand is required for heme uptake in HmuT.
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Affiliation(s)
| | - Neval Akbas
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30302-3965
| | - Seth A. Adrian
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050
| | - Gudrun S. Lukat-Rodgers
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050
| | - Daniel P. Collins
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - John H. Dawson
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - Courtni E. Allen
- Laboratory of Respiratory and Special Pathogens, Division of Bacterial, Parasitic, and Allergenic Products, Center for Biologics Evaluation, and Research, Food and Drug Administration, Silver Spring, Maryland 20993
| | - Michael P. Schmitt
- Laboratory of Respiratory and Special Pathogens, Division of Bacterial, Parasitic, and Allergenic Products, Center for Biologics Evaluation, and Research, Food and Drug Administration, Silver Spring, Maryland 20993
| | - Kenton R. Rodgers
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050
| | - Dabney W. Dixon
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30302-3965
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20
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Abi-Khalil E, Segond D, Terpstra T, André-Leroux G, Kallassy M, Lereclus D, Bou-Abdallah F, Nielsen-Leroux C. Heme interplay between IlsA and IsdC: Two structurally different surface proteins from Bacillus cereus. Biochim Biophys Acta Gen Subj 2015; 1850:1930-41. [PMID: 26093289 DOI: 10.1016/j.bbagen.2015.06.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 06/04/2015] [Accepted: 06/16/2015] [Indexed: 12/16/2022]
Abstract
BACKGROUND Iron is an essential element for bacterial growth and virulence. Because of its limited bioavailability in the host, bacteria have adapted several strategies to acquire iron during infection. In the human opportunistic bacteria Bacillus cereus, a surface protein IlsA is shown to be involved in iron acquisition from both ferritin and hemoproteins. IlsA has a modular structure consisting of a NEAT (Near Iron transporter) domain at the N-terminus, several LRR (Leucine Rich Repeat) motifs and a SLH (Surface Layer Homology) domain likely involved in anchoring the protein to the cell surface. METHODS Isothermal titration calorimetry, UV-Vis spectrophotometry, affinity chromatography and rapid kinetics stopped-flow measurements were employed to probe the binding and transfer of hemin between two different B. cereus surface proteins (IlsA and IsdC). RESULTS IlsA binds hemin via the NEAT domain and is able to extract heme from hemoglobin whereas the LRR domain alone is not involved in these processes. A rapid hemin transfer from hemin-containing IlsA (holo-IlsA) to hemin-free IsdC (apo-IsdC) is demonstrated. CONCLUSIONS For the first time, it is shown that two different B. cereus surface proteins (IlsA and IsdC) can interact and transfer heme suggesting their involvement in B. cereus heme acquisition. GENERAL SIGNIFICANCE An important role for the complete Isd system in heme-associated bacterial growth is demonstrated and new insights into the interplay between an Isd NEAT surface protein and an IlsA-NEAT-LRR protein, both of which appear to be involved in heme-iron acquisition in B. cereus are revealed.
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Affiliation(s)
- Elise Abi-Khalil
- INRA, UMR 1319 Micalis-AgroParisTech, AgroParisTech UMR Micalis, F-78352 Jouy en Josas, France; Laboratory of Biotechnology, Saint-Joseph University, Beyrouth, Lebanon; Department of Chemistry, State University of New York at Potsdam, Potsdam, NY 13676, USA
| | - Diego Segond
- INRA, UMR 1319 Micalis-AgroParisTech, AgroParisTech UMR Micalis, F-78352 Jouy en Josas, France
| | - Tyson Terpstra
- Department of Chemistry, State University of New York at Potsdam, Potsdam, NY 13676, USA
| | | | - Mireille Kallassy
- Laboratory of Biotechnology, Saint-Joseph University, Beyrouth, Lebanon
| | - Didier Lereclus
- INRA, UMR 1319 Micalis-AgroParisTech, AgroParisTech UMR Micalis, F-78352 Jouy en Josas, France
| | - Fadi Bou-Abdallah
- Department of Chemistry, State University of New York at Potsdam, Potsdam, NY 13676, USA
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Sheldon JR, Heinrichs DE. Recent developments in understanding the iron acquisition strategies of gram positive pathogens. FEMS Microbiol Rev 2015; 39:592-630. [DOI: 10.1093/femsre/fuv009] [Citation(s) in RCA: 166] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/04/2015] [Indexed: 12/26/2022] Open
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