scholarly journals PPE Surface Proteins Are Required for Heme Utilization by Mycobacterium tuberculosis

mBio ◽  
2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Avishek Mitra ◽  
Alexander Speer ◽  
Kan Lin ◽  
Sabine Ehrt ◽  
Michael Niederweis
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Human Body ◽  
Iron Acquisition ◽  
Bacterial Pathogens ◽  
Surface Proteins ◽  
Resonance Spectroscopy ◽  
Heme Uptake ◽  
Human Host ◽  
Essential Nutrient ◽  
Growth Experiments

ABSTRACT Iron is essential for replication of Mycobacterium tuberculosis, but iron is efficiently sequestered in the human host during infection. Heme constitutes the largest iron reservoir in the human body and is utilized by many bacterial pathogens as an iron source. While heme acquisition is well studied in other bacterial pathogens, little is known in M. tuberculosis. To identify proteins involved in heme utilization by M. tuberculosis, a transposon mutant library was screened for resistance to the toxic heme analog gallium(III)-porphyrin (Ga-PIX). Inactivation of the ppe36, ppe62, and rv0265c genes resulted in resistance to Ga-PIX. Growth experiments using isogenic M. tuberculosis deletion mutants showed that PPE36 is essential for heme utilization by M. tuberculosis, while the functions of PPE62 and Rv0265c are partially redundant. None of the genes restored growth of the heterologous M. tuberculosis mutants, indicating that the proteins encoded by the genes have separate functions. PPE36, PPE62, and Rv0265c bind heme as shown by surface plasmon resonance spectroscopy and are associated with membranes. Both PPE36 and PPE62 proteins are cell surface accessible, while the Rv0265c protein is probably located in the periplasm. PPE36 and PPE62 are, to our knowledge, the first proline-proline-glutamate (PPE) proteins of M. tuberculosis that bind small molecules and are involved in nutrient acquisition. The absence of a virulence defect of the ppe36 deletion mutant indicates that the different iron acquisition pathways of M. tuberculosis may substitute for each other during growth and persistence in mice. The emerging model of heme utilization by M. tuberculosis as derived from this study is substantially different from those of other bacteria. IMPORTANCE Tuberculosis is caused by Mycobacterium tuberculosis and is a devastating disease affecting eight million people each year. Iron is an essential nutrient for replication of M. tuberculosis in the human host. More than 70% of iron in the human body is bound in heme. Not surprisingly, many bacterial pathogens, including M. tuberculosis, are able to acquire iron from heme. However, the mechanism of heme uptake by M. tuberculosis is poorly understood. We have identified two novel surface proteins that bind heme and are required for heme utilization by M. tuberculosis. These findings constitute a major advancement of our understanding of iron acquisition by M. tuberculosis and show that M. tuberculosis has evolved heme uptake systems different from the paradigms established by other bacteria. IMPORTANCE Tuberculosis is caused by Mycobacterium tuberculosis and is a devastating disease affecting eight million people each year. Iron is an essential nutrient for replication of M. tuberculosis in the human host. More than 70% of iron in the human body is bound in heme. Not surprisingly, many bacterial pathogens, including M. tuberculosis, are able to acquire iron from heme. However, the mechanism of heme uptake by M. tuberculosis is poorly understood. We have identified two novel surface proteins that bind heme and are required for heme utilization by M. tuberculosis. These findings constitute a major advancement of our understanding of iron acquisition by M. tuberculosis and show that M. tuberculosis has evolved heme uptake systems different from the paradigms established by other bacteria.

scholarly journals Heme and hemoglobin utilization by Mycobacterium tuberculosis

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Avishek Mitra ◽  
Ying-Hui Ko ◽  
Gino Cingolani ◽  
Michael Niederweis
Keyword(s):  
Crystal Structure ◽  
Mycobacterium Tuberculosis ◽  
Cell Surface ◽  
Human Body ◽  
Iron Acquisition ◽  
Outer Membrane Proteins ◽  
Blood Protein ◽  
Heme Binding ◽  
Heme Uptake ◽  
Substrate Binding Protein

Abstract Iron is essential for growth of Mycobacterium tuberculosis (Mtb), but most iron in the human body is stored in heme within hemoglobin. Here, we demonstrate that the substrate-binding protein DppA of the inner membrane Dpp transporter is required for heme and hemoglobin utilization by Mtb. The 1.27 Å crystal structure of DppA shows a tetrapeptide bound in the protein core and a large solvent-exposed crevice for heme binding. Mutation of arginine 179 in this cleft eliminates heme binding to DppA and prevents heme utilization by Mtb. The outer membrane proteins PPE36 and PPE62 are also required for heme and hemoglobin utilization, indicating that these pathways converge at the cell surface of Mtb. Albumin, the most abundant blood protein, binds heme specifically and bypasses the requirements for PPE36, PPE62 and Dpp. Thus, our study reveals albumin-dependent and -independent heme uptake pathways, highlighting the importance of iron acquisition from heme for Mtb.

scholarly journals The Mycobacterium tuberculosis High-Affinity Iron Importer, IrtA, Contains an FAD-Binding Domain

2009 ◽  
Vol 192 (3) ◽  
pp. 861-869 ◽  
Author(s):  
Michelle B. Ryndak ◽  
Shuishu Wang ◽  
Issar Smith ◽  
G. Marcela Rodriguez
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Iron Acquisition ◽  
Binding Domain ◽  
Amino Terminus ◽  
High Affinity ◽  
Iron Deficient ◽  
Essential Nutrient ◽  
Iron Binding Proteins ◽  
Fad Binding

ABSTRACT Iron is an essential nutrient not freely available to microorganisms infecting mammals. To overcome iron deficiency, bacteria have evolved various strategies including the synthesis and secretion of high-affinity iron chelators known as siderophores. The siderophores produced and secreted by Mycobacterium tuberculosis, exomycobactins, compete for iron with host iron-binding proteins and, together with the iron-regulated ABC transporter IrtAB, are required for the survival of M. tuberculosis in iron deficient conditions and for normal replication in macrophages and in mice. This study further characterizes the role of IrtAB in M. tuberculosis iron acquisition. Our results demonstrate a role for IrtAB in iron import and show that the amino terminus domain of IrtA is a flavin-adenine dinucleotide-binding domain essential for iron acquisition. These results suggest a model in which the amino terminus of IrtA functions to couple iron transport and assimilation.

scholarly journals The Serratia marcescens Siderophore Serratiochelin Is Necessary for Full Virulence during Bloodstream Infection

2020 ◽  
Vol 88 (8) ◽  
Author(s):  
Danelle R. Weakland ◽  
Sara N. Smith ◽  
Bailey Bell ◽  
Ashootosh Tripathi ◽  
Harry L. T. Mobley
Keyword(s):  
Serratia Marcescens ◽  
Bloodstream Infection ◽  
Iron Acquisition ◽  
Gene Clusters ◽  
Clinical Isolates ◽  
Wild Type ◽  
Serratia Plymuthica ◽  
Content Type ◽  
Cas Assay ◽  
Essential Nutrient

ABSTRACT Serratia marcescens is a bacterium frequently found in the environment, but over the last several decades it has evolved into a concerning clinical pathogen, causing fatal bacteremia. To establish such infections, pathogens require specific nutrients; one very limited but essential nutrient is iron. We sought to characterize the iron acquisition systems in S. marcescens isolate UMH9, which was recovered from a clinical bloodstream infection. Using RNA sequencing (RNA-seq), we identified two predicted siderophore gene clusters (cbs and sch) that were regulated by iron. Mutants were constructed to delete each iron acquisition locus individually and in conjunction, generating both single and double mutants for the putative siderophore systems. Mutants lacking the sch gene cluster lost their iron-chelating ability as quantified by the chrome azurol S (CAS) assay, whereas the cbs mutant retained wild-type activity. Mass spectrometry-based analysis identified the chelating siderophore to be serratiochelin, a siderophore previously identified in Serratia plymuthica. Serratiochelin-producing mutants also displayed a decreased growth rate under iron-limited conditions created by dipyridyl added to LB medium. Additionally, mutants lacking serratiochelin were significantly outcompeted during cochallenge with wild-type UMH9 in the kidneys and spleen after inoculation via the tail vein in a bacteremia mouse model. This result was further confirmed by an independent challenge, suggesting that serratiochelin is required for full S. marcescens pathogenesis in the bloodstream. Nine other clinical isolates have at least 90% protein identity to the UMH9 serratiochelin system; therefore, our results are broadly applicable to emerging clinical isolates of S. marcescens causing bacteremia.

Iron Acquisition Strategies of Bacterial Pathogens

2016 ◽  
pp. 43-85 ◽  
Author(s):  
Jessica R. Sheldon ◽  
Holly A. Laakso ◽  
David E. Heinrichs
Keyword(s):  
Iron Acquisition ◽  
Bacterial Pathogens ◽  
Acquisition Strategies

The Corynebacterium diphtheriae HbpA hemoglobin-binding protein contains a domain that is critical for hemoprotein-binding, cellular localization and function.

2021 ◽  
Author(s):  
Lindsey R. Lyman ◽  
Eric D. Peng ◽  
Michael P. Schmitt
Keyword(s):  
Cellular Localization ◽  
Binding Protein ◽  
Protein Localization ◽  
Iron Acquisition ◽  
Corynebacterium Diphtheriae ◽  
Terminal Region ◽  
Surface Proteins ◽  
Size Exclusion ◽  
Transport Systems ◽  
Iron Source

The acquisition of hemin-iron from hemoglobin-haptoglobin (Hb-Hp) by Corynebacterium diphtheriae requires the iron-regulated surface proteins HtaA, ChtA, ChtC, and the recently identified Hb-Hp binding protein HbpA. We previously showed that a purified form of HbpA (HbpA-S), lacking the C-terminal region, was able to bind Hb-Hp. In this study, we show that the C-terminal region of HbpA significantly enhances binding to Hb-Hp. A purified form of HbpA that includes the C-terminal domain (HbpA-FL) exhibits much stronger binding to Hb-Hp than HbpA-S. Size exclusion chromatography (SEC) showed that HbpA-FL as well as HtaA-FL, ChtA-FL, and ChtC-FL exist as high molecular weight complexes, while HbpA-S is present as a monomer, indicating that the C-terminal region is required for formation of large aggregates. Growth studies showed that expression of HbpA-FL in the Δ hbpA mutant restored wild-type levels of growth in low-iron medium that contained Hb-Hp as the sole iron source, while HbpA-S failed to complement the Δ hbpA mutant. Protein localization studies in C. diphtheriae showed that HbpA-FL is present in both in the supernatant and in the membrane fractions, and that the C-terminal region is required for membrane anchoring. Purified HbpA-FL was able to enhance growth of the Δ hbpA mutant when added to culture medium that contained Hb-Hp as a sole iron source, suggesting that secreted HbpA is involved in the use of hemin-iron from Hb-Hp. These studies extend our understanding of this novel Hb-Hp binding protein in this important human pathogen. IMPORTANCE Hemoproteins, such as Hb, are an abundant source of iron in humans and are proposed to be required by numerous pathogens to cause disease. In this report, we expand on our previous studies in further defining the role of HbpA in hemin-iron acquisition in C. diphtheriae . HbpA is unique to C. diphtheriae , and appears to function unlike any previously described bacterial iron-regulated Hb- or Hb-Hp-binding protein. HbpA is both secreted and present in the membrane, and exists as a large aggregate that enhances its ability to bind Hb-Hp and promote hemin-iron uptake. Current studies with HbpA will increase our understanding of iron transport systems in C. diphtheriae .

Host glyceraldehyde-3-phosphate dehydrogenase-mediated iron acquisition is hijacked by intraphagosomal Mycobacterium tuberculosis

2022 ◽  
Vol 79 (1) ◽  
Author(s):  
Anil Patidar ◽  
Himanshu Malhotra ◽  
Surbhi Chaudhary ◽  
Manoj Kumar ◽  
Rahul Dilawari ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Iron Acquisition

scholarly journals Mycobacterium tuberculosis infection of host cells in space and time

2019 ◽  
Vol 43 (4) ◽  
pp. 341-361 ◽  
Author(s):  
Claudio Bussi ◽  
Maximiliano G Gutierrez
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Host Cell ◽  
Cell Biology ◽  
Current Knowledge ◽  
Bacterial Pathogen ◽  
Infectious Agent ◽  
Host Cells ◽  
Cellular Mechanisms ◽  
Mycobacterium Tuberculosis Infection ◽  
Human Host

ABSTRACTTuberculosis (TB) caused by the bacterial pathogen Mycobacterium tuberculosis (Mtb) remains one of the deadliest infectious diseases with over a billion deaths in the past 200 years (Paulson 2013). TB causes more deaths worldwide than any other single infectious agent, with 10.4 million new cases and close to 1.7 million deaths in 2017. The obstacles that make TB hard to treat and eradicate are intrinsically linked to the intracellular lifestyle of Mtb. Mtb needs to replicate within human cells to disseminate to other individuals and cause disease. However, we still do not completely understand how Mtb manages to survive within eukaryotic cells and why some cells are able to eradicate this lethal pathogen. Here, we summarise the current knowledge of the complex host cell-pathogen interactions in TB and review the cellular mechanisms operating at the interface between Mtb and the human host cell, highlighting the technical and methodological challenges to investigating the cell biology of human host cell-Mtb interactions.

Iron acquisition by Gram-positive bacterial pathogens

2002 ◽  
Vol 4 (11) ◽  
pp. 1149-1156 ◽  
Author(s):  
Jeremy S Brown ◽  
David W Holden
Keyword(s):  
Iron Acquisition ◽  
Bacterial Pathogens ◽  
Gram Positive

scholarly journals Rhizobactin B is the preferred siderophore by a novel Pseudomonas isolate to obtain iron from dissolved organic matter in peatlands

BioMetals ◽  
2020 ◽  
Vol 33 (6) ◽  
pp. 415-433
Author(s):  
Stefan Kügler ◽  
Rebecca E. Cooper ◽  
Johanna Boessneck ◽  
Kirsten Küsel ◽  
Thomas Wichard
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Ligand Exchange ◽  
High Resolution Mass Spectrometry ◽  
Iron Acquisition ◽  
Water Extract ◽  
Resonance Spectroscopy ◽  
Biological Processes ◽  
Polycarboxylic Acid ◽  
Chelating Compounds

AbstractBacteria often release diverse iron-chelating compounds called siderophores to scavenge iron from the environment for many essential biological processes. In peatlands, where the biogeochemical cycle of iron and dissolved organic matter (DOM) are coupled, bacterial iron acquisition can be challenging even at high total iron concentrations. We found that the bacterium Pseudomonas sp. FEN, isolated from an Fe-rich peatland in the Northern Bavarian Fichtelgebirge (Germany), released an unprecedented siderophore for its genus. High-resolution mass spectrometry (HR-MS) using metal isotope-coded profiling (MICP), MS/MS experiments, and nuclear magnetic resonance spectroscopy (NMR) identified the amino polycarboxylic acid rhizobactin and a novel derivative at even higher amounts, which was named rhizobactin B. Interestingly, pyoverdine-like siderophores, typical for this genus, were not detected. With peat water extract (PWE), studies revealed that rhizobactin B could acquire Fe complexed by DOM, potentially through a TonB-dependent transporter, implying a higher Fe binding constant of rhizobactin B than DOM. The further uptake of Fe-rhizobactin B by Pseudomonas sp. FEN suggested its role as a siderophore. Rhizobactin B can complex several other metals, including Al, Cu, Mo, and Zn. The study demonstrates that the utilization of rhizobactin B can increase the Fe availability for Pseudomonas sp. FEN through ligand exchange with Fe-DOM, which has implications for the biogeochemical cycling of Fe in this peatland.

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