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Inomata T, Endo S, Ido H, Mori R, Iwai Y, Ozawa T, Masuda H. Iron(III) Complexes with Hybrid-Type Artificial Siderophores Containing Catecholate and Hydroxamate Sites. Inorg Chem 2023; 62:16362-16377. [PMID: 37738382 DOI: 10.1021/acs.inorgchem.3c01786] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/24/2023]
Abstract
Two hybrid-type artificial siderophore ligands containing both catecholate and hydroxamate groups as iron-capturing sites, bis(2,3-dihydroxybenzamidepropyl)mono[2-propyl]aminomethane (H5LC2H1) and mono(2,3-dihydroxybenzamide-propyl)bis[2-propyl]aminomethane (H4LC1H2), were designed and synthesized. Iron(III) complexes, K2[FeIIILC2H1] and K[FeIIILC1H2], were prepared and characterized spectroscopically, potentiometrically, and electrochemically. The results were compared with those previously reported for iron complexes with non-hybridized siderophores containing either catecholate or hydroxamate groups, K3[FeIIILC3] and [FeIIILH3]. Both K2[FeIIILC2H1] and K[FeIIILC1H2] formed six-coordinate octahedral iron(III) complexes. Evaluation of the thermodynamic properties of the complexes in an aqueous solution indicated high log β values of 37.3 and 32.3 for K2[FeIIILC2H1] and K[FeIIILC1H2], respectively, which were intermediate between those of K3[FeIIILC3] (44.2) and [FeIIILH3] (31). Evaluation of the ultraviolet-visible and Fourier transform infrared spectra of the two hybrid siderophore-iron complexes under different pH or pD (potential of dueterium) conditions showed that the protonation of K2[FeIIILC2H1] and K[FeIIILC1H2] generated the corresponding protonated species, [FeIIIHnLC2H1](2-n)- and [FeIIIHnLC1H2](1-n)-, accompanied by a significant change in the coordination mode. The protonated hybrid-type siderophore-iron complexes showed high reduction potentials, which were well within the range of those of biological reductants. The results suggest that the hybrid-type siderophore easily releases an iron(III) ion at low pH. The biological activity of the four artificial siderophore-iron complexes against Microbacterium flavescens and Escherichia coli clearly depends on the structural differences between the complexes. This finding demonstrates that the changes in the coordination sites of the siderophores enable close control of the interactions between the siderophores and receptors in the cell membrane.
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Affiliation(s)
- Tomohiko Inomata
- Department of Life Science and Applied Chemistry, Graduate School of Science, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Suguru Endo
- Department of Life Science and Applied Chemistry, Graduate School of Science, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Hiroki Ido
- Department of Life Science and Applied Chemistry, Graduate School of Science, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Reon Mori
- Department of Life Science and Applied Chemistry, Graduate School of Science, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Yusuke Iwai
- Department of Life Science and Applied Chemistry, Graduate School of Science, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Tomohiro Ozawa
- Department of Life Science and Applied Chemistry, Graduate School of Science, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Hideki Masuda
- Department of Life Science and Applied Chemistry, Graduate School of Science, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
- Department of Applied Chemistry, Aichi Institute of Technology, 1247 Yachigusa, Yakusa-cho, Toyota 470-0392, Japan
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2
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Zou Z, Robinson JI, Steinberg LK, Henderson JP. Uropathogenic Escherichia coli wield enterobactin-derived catabolites as siderophores. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.25.550588. [PMID: 37546885 PMCID: PMC10402112 DOI: 10.1101/2023.07.25.550588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Uropathogenic E. coli (UPEC) secrete multiple siderophore types to scavenge extracellular iron(III) ions during clinical urinary tract infections, despite the metabolic costs of biosynthesis. Here we find the siderophore enterobactin and its related products to be prominent components of the iron-responsive extracellular metabolome of a model UPEC strain. Using defined enterobactin biosynthesis and import mutants, we identify lower molecular weight, dimeric exometabolites as products of incomplete siderophore catabolism, rather than prematurely released biosynthetic intermediates. In E. coli, iron acquisition from iron(III)-enterobactin complexes requires intracellular esterases that hydrolyze the siderophore. Although UPEC are equipped to consume the products of completely hydrolyzed enterobactin, we find that enterobactin and its derivatives may be incompletely hydrolyzed to yield products with retained siderophore activity. These results are consistent with catabolic inefficiency as means to obtain more than one iron ion per siderophore molecule. This is compatible with an evolved UPEC strategy to maximize the nutritional returns from metabolic investments in siderophore biosynthesis.
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Affiliation(s)
- Zongsen Zou
- Center for Women’s Infectious Diseases Research, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Internal Medicine, Division of Infectious Diseases, Washington University School of Medicine, St. Louis, Missouri, USA
| | - John I. Robinson
- Center for Women’s Infectious Diseases Research, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Internal Medicine, Division of Infectious Diseases, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Lindsey K. Steinberg
- Center for Women’s Infectious Diseases Research, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Internal Medicine, Division of Infectious Diseases, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Jeffrey P. Henderson
- Center for Women’s Infectious Diseases Research, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Internal Medicine, Division of Infectious Diseases, Washington University School of Medicine, St. Louis, Missouri, USA
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3
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Liu Z, Huang T, Shi Q, Deng Z, Lin S. Catechol siderophores framed on 2,3-dihydroxybenzoyl-L-serine from Streptomyces varsoviensis. Front Microbiol 2023; 14:1182449. [PMID: 37206338 PMCID: PMC10188961 DOI: 10.3389/fmicb.2023.1182449] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 04/10/2023] [Indexed: 05/21/2023] Open
Abstract
Enterobactin is an archetypical catecholate siderophore that plays a key role in the acquisition of ferric iron by microorganisms. Catechol moieties have been shown to be promising siderophore cores. Variants of the conserved 2,3-dihydroxybenzoate (DHB) moiety with structural modifications expand the bioactivity. Streptomyces are characterized by metabolites with diverse structures. The genomic sequence of Streptomyces varsoviensis indicated that it possessed a biosynthetic gene cluster for DHB containing siderophores and metabolic profiling revealed metabolites correlated with catechol-type natural products. Here, we report the discovery of a series of catecholate siderophores produced by S. varsoviensis and a scale-up fermentation was performed to purify these compounds for structural elucidation. A biosynthetic route for the catecholate siderophores is also proposed. These new structural features enrich the structural diversity of the enterobactin family compounds. One of the new linear enterobactin congeners shows moderate activity against a food-borne pathogen Listeria monocytogenes. This work demonstrated that changing culture conditions is still a promising approach to explore unexplored chemical diversity. The availability of the biosynthetic machinery will enrich the genetic toolbox of catechol siderophores and facilitate such engineering efforts.
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Affiliation(s)
- Zhixiang Liu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory on Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Tingting Huang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory on Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, China
- Haihe Laboratory of Synthetic Biology, Tianjin, China
| | - Qing Shi
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory on Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Zixin Deng
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory on Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, China
- Haihe Laboratory of Synthetic Biology, Tianjin, China
| | - Shuangjun Lin
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory on Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, China
- Haihe Laboratory of Synthetic Biology, Tianjin, China
- Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai, China
- *Correspondence: Shuangjun Lin,
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4
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Mass spectrometry based targeted metabolomics precisely characterized new functional metabolites that regulate biofilm formation in Escherichia coli. Anal Chim Acta 2021; 1145:26-36. [DOI: 10.1016/j.aca.2020.12.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 12/08/2020] [Accepted: 12/14/2020] [Indexed: 12/17/2022]
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Saha P, Yeoh BS, Xiao X, Golonka RM, Abokor AA, Wenceslau CF, Shah YM, Joe B, Vijay-Kumar M. Enterobactin induces the chemokine, interleukin-8, from intestinal epithelia by chelating intracellular iron. Gut Microbes 2020; 12:1-18. [PMID: 33171063 PMCID: PMC7671005 DOI: 10.1080/19490976.2020.1841548] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Iron is an indispensable nutrient for both mammals and microbes. Bacteria synthesize siderophores to sequester host iron, whereas lipocalin 2 (Lcn2) is the host defense protein that prevent this iron thievery. Enterobactin (Ent) is a catecholate-type siderophore that has one of the strongest known affinities for iron. Intestinal epithelial cells (IECs) are adjacent to large microbial population and are in contact with microbial products, including Ent. We undertook this study to investigate whether a single stimulus of Ent could affect IEC functions. Using three human IEC cell-lines with differential basal levels of Lcn2 (i.e. HT29 < DLD-1 < Caco-2/BBe), we demonstrated that iron-free Ent could induce a dose-dependent secretion of the pro-inflammatory chemokine, interleukin 8 (IL-8), in HT29 and DLD-1 IECs, but not in Caco-2/BBe. Ent-induced IL-8 secretion was dependent on chelation of the labile iron pool and on the levels of intracellular Lcn2. Accordingly, IL-8 secretion by Ent-treated HT29 cells could be substantially inhibited by either saturating Ent with iron or by adding exogenous Lcn2 to the cells. IL-8 production by Ent could be further potentiated when co-stimulated with other microbial products (i.e. flagellin, lipopolysaccharide). Water-soluble microbial siderophores did not induce IL-8 production, which signifies that IECs are specifically responding to the lipid-soluble Ent. Intriguingly, formyl peptide receptor (FPR) antagonists (i.e. Boc2, cyclosporine H) abrogated Ent-induced IL-8, implicating that such IEC response could be, in part, dependent on FPR. Taken together, these results demonstrate that IECs sense Ent as a danger signal, where its recognition results in IL-8 secretion.
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Affiliation(s)
- Piu Saha
- UT Microbiome Consortium, Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Beng San Yeoh
- UT Microbiome Consortium, Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Xia Xiao
- Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Rachel M. Golonka
- UT Microbiome Consortium, Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Ahmed A. Abokor
- UT Microbiome Consortium, Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Camilla F. Wenceslau
- UT Microbiome Consortium, Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Yatrik M. Shah
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA,Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA,Rogel Cancer Center, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Bina Joe
- UT Microbiome Consortium, Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Matam Vijay-Kumar
- UT Microbiome Consortium, Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA,CONTACT Matam Vijay-Kumar Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH43614, USA
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6
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Wellawa DH, Allan B, White AP, Köster W. Iron-Uptake Systems of Chicken-Associated Salmonella Serovars and Their Role in Colonizing the Avian Host. Microorganisms 2020; 8:E1203. [PMID: 32784620 PMCID: PMC7465098 DOI: 10.3390/microorganisms8081203] [Citation(s) in RCA: 9] [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: 07/15/2020] [Revised: 07/30/2020] [Accepted: 07/31/2020] [Indexed: 01/09/2023] Open
Abstract
Iron is an essential micronutrient for most bacteria. Salmonella enterica strains, representing human and animal pathogens, have adopted several mechanisms to sequester iron from the environment depending on availability and source. Chickens act as a major reservoir for Salmonella enterica strains which can lead to outbreaks of human salmonellosis. In this review article we summarize the current understanding of the contribution of iron-uptake systems to the virulence of non-typhoidal S. enterica strains in colonizing chickens. We aim to address the gap in knowledge in this field, to help understand and define the interactions between S. enterica and these important hosts, in comparison to mammalian models.
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Affiliation(s)
- Dinesh H. Wellawa
- Vaccine & Infectious Disease Organization-International Vaccine Centre, University of Saskatchewan, 120 Veterinary Rd., Saskatoon, SK S7N 5E3, Canada; (D.H.W.); (B.A.); (A.P.W.)
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada
| | - Brenda Allan
- Vaccine & Infectious Disease Organization-International Vaccine Centre, University of Saskatchewan, 120 Veterinary Rd., Saskatoon, SK S7N 5E3, Canada; (D.H.W.); (B.A.); (A.P.W.)
| | - Aaron P. White
- Vaccine & Infectious Disease Organization-International Vaccine Centre, University of Saskatchewan, 120 Veterinary Rd., Saskatoon, SK S7N 5E3, Canada; (D.H.W.); (B.A.); (A.P.W.)
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada
| | - Wolfgang Köster
- Vaccine & Infectious Disease Organization-International Vaccine Centre, University of Saskatchewan, 120 Veterinary Rd., Saskatoon, SK S7N 5E3, Canada; (D.H.W.); (B.A.); (A.P.W.)
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada
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7
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Julien LA, Fau C, Baron F, Bonnassie S, Guérin-Dubiard C, Nau F, Gautier M, Karatzas KA, Jan S, Andrews SC. The Three Lipocalins of Egg-White: Only Ex-FABP Inhibits Siderophore-Dependent Iron Sequestration by Salmonella Enteritidis. Front Microbiol 2020; 11:913. [PMID: 32477312 PMCID: PMC7242566 DOI: 10.3389/fmicb.2020.00913] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 04/17/2020] [Indexed: 12/15/2022] Open
Abstract
Salmonella Enteritidis is the most prevalent food-borne pathogen associated with egg-related outbreaks in the European Union. During egg colonization, S. Enteritidis must resist the powerful anti-bacterial activities of egg white (EW) and overcome ovotransferrin-imposed iron-restriction (the most important anti-bacterial mechanism of EW). Many pathogens respond to iron restriction by secreting iron-chelating chemicals called siderophores but EW contains a siderophore-sequestering "lipocalin" protein (Ex-FABP) that is predicted to limit the usefulness of siderophores in EW. S. Enteritidis produces two siderophores: enterobactin, which is strongly bound by Ex-FABP; and the di-glucosylated enterobactin-derivative, salmochelin (a so-called "stealth" siderophore), which is not recognized by Ex-FABP. Thus, production of salmochelin may allow S. Enteritidis to escape Ex-FABP-mediated growth inhibition under iron restriction although it is unclear whether its EW concentration is sufficient to inhibit pathogens. Further, two other lipocalins (Cal-γ and α-1-ovoglycoprotein) are found in EW but their siderophore sequestration potential remains unexplored. In addition, the effect of EW lipocalins on the major EW pathogen, S. Enteritidis, has yet to be reported. We overexpressed and purified the three lipocalins of EW and investigated their ability to interact with the siderophores of S. Enteritidis, as well as their EW concentrations. The results show that Ex-FABP is present in EW at concentrations (5.1 μM) sufficient to inhibit growth of a salmochelin-deficient S. Enteritidis mutant under iron restriction but has little impact on the salmochelin-producing wildtype. Neither Cal-γ nor α-1-ovoglycoprotein bind salmochelin or enterobactin, nor do they inhibit iron-restricted growth of S. Enteritidis. However, both are present in EW at significant concentrations (5.6 and 233 μM, respectively) indicating that α-1-ovoglycoprotein is the 4th most abundant protein in EW, with Cal-γ and Ex-FABP at 11th and 12th most abundant. Further, we confirm the preference (16-fold) of Ex-FABP for the ferrated form (K d of 5.3 nM) of enterobactin over the iron-free form (K d of 86.2 nM), and its lack of affinity for salmochelin. In conclusion, our findings show that salmochelin production by S. Enteritidis enables this key egg-associated pathogen to overcome the enterobactin-sequestration activity of Ex-FABP when this lipocalin is provided at levels found in EW.
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Affiliation(s)
- Louis Alex Julien
- School of Biological Sciences, University of Reading, Reading, United Kingdom
- STLO, INRAE, Institut Agro, Rennes, France
| | - Clémence Fau
- Inserm 1107, Neuro-Dol, Université Clermont Auvergne, Clermont-Ferrand, France
| | | | - Sylvie Bonnassie
- STLO, INRAE, Institut Agro, Rennes, France
- UFR Sciences de la Vie et de l’Environnement, Université de Rennes I, Rennes, France
| | | | | | | | | | - Sophie Jan
- STLO, INRAE, Institut Agro, Rennes, France
| | - Simon Colin Andrews
- School of Biological Sciences, University of Reading, Reading, United Kingdom
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8
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Guo C, Steinberg LK, Cheng M, Song JH, Henderson JP, Gross ML. Site-Specific Siderocalin Binding to Ferric and Ferric-Free Enterobactin As Revealed by Mass Spectrometry. ACS Chem Biol 2020; 15:1154-1160. [PMID: 31869199 PMCID: PMC7236765 DOI: 10.1021/acschembio.9b00741] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 12/23/2019] [Indexed: 11/29/2022]
Abstract
Both host and pathogen competitively manipulate coordination environments during bacterial infections. Human cells release the innate immune protein siderocalin (Scn, also known as lipocalin-2/Lcn2, neutrophil gelatinase-associated lipocalin/NGAL) that can inhibit bacterial growth by sequestering iron in a ferric complex with enterobactin (Ent), the ubiquitous Escherichia coli siderophore. Pathogenic E. coli use the virulence-associated esterase IroE to linearize the Ent cyclic trilactone to linear enterobactin (lin-Ent). We characterized lin-Ent interactions with Scn by using native mass spectrometry (MS) with hydrogen-deuterium exchange (HDX) and Lys/Arg specific covalent footprinting. These approaches support 1:1 binding of both Fe(III)-lin-Ent to Scn and iron-free lin-Ent to Scn. Both ferric and nonferric lin-Ent localize to all three pockets of the Scn calyx, consistent with Scn capture of lin-Ent both before and after Fe(III) chelation. These findings raise the possibility that Scn neutralizes both siderophores and siderophore-bound iron during infections. This integrated, MS-based approach circumvents the limitations that frustrate traditional structural approaches to examining Scn interactions with enterobactin-based ligands.
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Affiliation(s)
- Chunyang Guo
- Department
of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Lindsey K. Steinberg
- Division
of Infectious Diseases, Department of Medicine, the Center for Women’s
Infectious Disease Research, Washington
University School of Medicine, St. Louis, Missouri 63110, United States
| | - Ming Cheng
- Department
of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Jong Hee Song
- Department
of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Jeffrey P. Henderson
- Division
of Infectious Diseases, Department of Medicine, the Center for Women’s
Infectious Disease Research, Washington
University School of Medicine, St. Louis, Missouri 63110, United States
| | - Michael L. Gross
- Department
of Chemistry, Washington University, St. Louis, Missouri 63130, United States
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Kong H, Cheng W, Wei H, Yuan Y, Yang Z, Zhang X. An overview of recent progress in siderophore-antibiotic conjugates. Eur J Med Chem 2019; 182:111615. [PMID: 31434038 DOI: 10.1016/j.ejmech.2019.111615] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 08/01/2019] [Accepted: 08/09/2019] [Indexed: 01/09/2023]
Abstract
Multi-drug resistant infections caused by Gram-negative bacteria have become one of the most important reasons for the failure of clinical anti-infective treatment. Siderophore-antibiotic conjugates, which were designed based on a "Trojan horse" strategy wherein features enabled active uptake to bypass the Gram-negative cell wall, have been expected to be a weapon for anti-infective treatment in the clinic. Herein, we review antibiotic drug design strategies based on mimics of nature siderophores reported in recent years, we also focus our attention on the relationship between the type of linker and the corresponding antibacterial activity.
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Affiliation(s)
- Huimin Kong
- Department of Pediatrics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Weiyan Cheng
- Department of Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China; Henan Key Laboratory of Precision Clinical Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Han Wei
- Department of Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China; Henan Key Laboratory of Precision Clinical Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Yongliang Yuan
- Department of Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China; Henan Key Laboratory of Precision Clinical Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Zhiheng Yang
- Department of Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China; Henan Key Laboratory of Precision Clinical Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
| | - Xiaojian Zhang
- Department of Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China; Henan Key Laboratory of Precision Clinical Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
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10
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The anti-bacterial iron-restriction defence mechanisms of egg white; the potential role of three lipocalin-like proteins in resistance against Salmonella. Biometals 2019; 32:453-467. [PMID: 30810876 PMCID: PMC6584246 DOI: 10.1007/s10534-019-00180-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Accepted: 01/25/2019] [Indexed: 11/26/2022]
Abstract
Salmonella enterica serovar Enteritidis (SE) is the most frequently-detected Salmonella in foodborne outbreaks in the European Union. Among such outbreaks, egg and egg products were identified as the most common vehicles of infection. Possibly, the major antibacterial property of egg white is iron restriction, which results from the presence of the iron-binding protein, ovotransferrin. To circumvent iron restriction, SE synthesise catecholate siderophores (i.e. enterobactin and salmochelin) that can chelate iron from host iron-binding proteins. Here, we highlight the role of lipocalin-like proteins found in egg white that could enhance egg-white iron restriction through sequestration of certain siderophores, including enterobactin. Indeed, it is now apparent that the egg-white lipocalin, Ex-FABP, can inhibit bacterial growth via its siderophore-binding capacity in vitro. However, it remains unclear whether Ex-FABP performs such a function in egg white or during bird infection. Regarding the two other lipocalins of egg white (Cal-γ and α-1-glycoprotein), there is currently no evidence to indicate that they sequester siderophores.
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11
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Wilde EJ, Blagova EV, Sanderson TJ, Raines DJ, Thomas RP, Routledge A, Duhme-Klair AK, Wilson KS. Mimicking salmochelin S1 and the interactions of its Fe(III) complex with periplasmic iron siderophore binding proteins CeuE and VctP. J Inorg Biochem 2018; 190:75-84. [PMID: 30384009 DOI: 10.1016/j.jinorgbio.2018.10.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 10/15/2018] [Accepted: 10/16/2018] [Indexed: 12/16/2022]
Abstract
A mimic of the tetradentate stealth siderophore salmochelin S1, was synthesised, characterised and shown to form Fe(III) complexes with ligand-to-metal ratios of 1:1 and 3:2. Circular dichroism spectroscopy confirmed that the periplasmic binding proteins CeuE and VctP of Campylobacter jejuni and Vibrio cholerae, respectively, bind the Fe(III) complex of the salmochelin mimic by preferentially selecting Λ-configured Fe(III) complexes. Intrinsic fluorescence quenching studies revealed that VctP binds Fe(III) complexes of the mimic and structurally-related catecholate ligands, such as enterobactin, bis(2, 3-dihydroxybenzoyl-l-serine) and bis(2, 3-dihydroxybenzoyl)-1, 5-pentanediamine with higher affinity than does CeuE. Both CeuE and VctP display a clear preference for the tetradentate bis(catecholates) over the tris(catecholate) siderophore enterobactin. These findings are consistent with reports that V. cholerae and C. jejuni utilise the enterobactin hydrolysis product bis(2, 3-dihydroxybenzoyl)-O-seryl serine for the acquisition of Fe(III) and suggest that the role of salmochelin S1 in the iron uptake of enteric pathogens merits further investigation.
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Affiliation(s)
- Ellis J Wilde
- Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5DD, UK; Department of Chemistry, University of York, Heslington, York YO10 5DD, UK
| | - Elena V Blagova
- Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5DD, UK
| | - Thomas J Sanderson
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK
| | - Daniel J Raines
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK
| | - Ross P Thomas
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK
| | - Anne Routledge
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK
| | | | - Keith S Wilson
- Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.
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12
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A reevaluation of iron binding by Mycobactin J. J Biol Inorg Chem 2018; 23:995-1007. [DOI: 10.1007/s00775-018-1592-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 07/03/2018] [Indexed: 12/21/2022]
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13
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Robinson AE, Heffernan JR, Henderson JP. The iron hand of uropathogenic Escherichia coli: the role of transition metal control in virulence. Future Microbiol 2018; 13:745-756. [PMID: 29870278 DOI: 10.2217/fmb-2017-0295] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The role of iron as a critical nutrient in pathogenic bacteria is widely regarded as having driven selection for iron acquisition systems among uropathogenic Escherichia coli (UPEC) isolates. Carriage of multiple transition metal acquisition systems in UPEC suggests that the human urinary tract manipulates metal-ion availability in many ways to resist infection. For siderophore systems in particular, recent studies have identified new roles for siderophore copper binding as well as production of siderophore-like inhibitors of iron uptake by other, competing bacterial species. Among these is a process of nutritional passivation of metal ions, in which uropathogens access these vital nutrients while simultaneously protecting themselves from their toxic potential. Here, we review these new findings within the current understanding of UPEC transition metal acquisition.
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Affiliation(s)
- Anne E Robinson
- Division of Infectious Diseases, Department of Medicine, Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - James R Heffernan
- Division of Infectious Diseases, Department of Medicine, Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jeffrey P Henderson
- Division of Infectious Diseases, Department of Medicine, Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, St. Louis, MO 63110, USA
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14
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Reitz ZL, Sandy M, Butler A. Biosynthetic considerations of triscatechol siderophores framed on serine and threonine macrolactone scaffolds. Metallomics 2018; 9:824-839. [PMID: 28594012 DOI: 10.1039/c7mt00111h] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Bacteria often produce siderophores to facilitate iron uptake. One of the most studied siderophores is enterobactin, the macrolactone trimer of 2,3-dihydroxybenzoyl-l-serine, produced by E. coli and many other enteric bacteria. Other siderophores are variants of enterobactin, with structural modifications including expansion of the tri-serine core to a tetra-serine macrolactone, substitution of l-serine with l-threonine, insertion of amino acids (i.e., Gly, l-Ala, d-Lys, d- and l-Arg, l-Orn), catechol glucosylation, and linearization of the tri-serine macrolactone core. In this review we summarize the current understanding of the biosyntheses of these enterobactin variants, placing them in contrast with the well-established biosynthesis of enterobactin.
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Affiliation(s)
- Zachary L Reitz
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106-9510, USA.
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15
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Zhang L, Liu R, Gung BW, Tindall S, Gonzalez JM, Halvorson JJ, Hagerman AE. Polyphenol-Aluminum Complex Formation: Implications for Aluminum Tolerance in Plants. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:3025-33. [PMID: 27022835 DOI: 10.1021/acs.jafc.6b00331] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Natural polyphenols may play an important role in aluminum detoxification in some plants. We examined the interaction between Al(3+) and the purified high molecular weight polyphenols pentagalloyl glucose (940 Da) and oenothein B (1568 Da), and the related compound methyl gallate (184 Da) at pH 4 and 6. We used spectrophotometric titration and chemometric modeling to determine stability constants and stoichiometries for the aluminum-phenol (AlL) complexes. The structures and spectral features of aluminum-methyl gallate complexes were evaluated with quantum chemical calculations. The high molecular weight polyphenols formed Al3L2 complexes with conditional stability constants (β) ∼ 1 × 10(23) at pH 6 and AlL complexes with β ∼ 1 × 10(5) at pH 4. Methyl gallate formed AlL complexes with β = 1 × 10(6) at pH 6 but did not complex aluminum at pH 4. At intermediate metal-to-polyphenol ratios, high molecular weight polyphenols formed insoluble Al complexes but methyl gallate complexes were soluble. The high molecular weight polyphenols have high affinities and solubility features that are favorable for a role in aluminum detoxification in the environment.
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Affiliation(s)
- Liangliang Zhang
- Institute of Chemical Industry of Forest Products, Chinese Academy of Forestry , Nanjing 210042, China
| | - Ruiqiang Liu
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Benjamin W Gung
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Steven Tindall
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Javier M Gonzalez
- National Soil Erosion Research Laboratory, USDA-ARS , West Lafayette, Indiana 47907, United States
| | - Jonathan J Halvorson
- Northern Great Plains Research Laboratory, USDA-ARS , Mandan, North Dakota 58554, United States
| | - Ann E Hagerman
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
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16
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Abstract
Siderophores are low molecular weight, high affinity iron chelating molecules that are essential virulence factors in many Gram-negative bacterial pathogens. Whereas the chemical structure of siderophores is extremely variable, the function of siderophores has been narrowly defined as the chelation and delivery of iron to bacteria for proliferation. The discovery of the host protein Lipocalin 2, capable of specifically sequestering the siderophore Enterobactin but not its glycosylated-derivative Salmochelin, indicated that diversity in structure could be an immune evasion mechanism that provides functional redundancy during infection. However, there is growing evidence that siderophores are specialized in their iron-acquisition functions, can perturb iron homeostasis in their hosts, and even bind non-iron metals to promote bacterial fitness. The combination of siderophores produced by a pathogen can enable inter-bacterial competition, modulate host cellular pathways, and determine the bacterial "replicative niche" during infection. This review will examine both classical and novel functions of siderophores to address the concept that siderophores are non-redundant virulence factors used to enhance bacterial pathogenesis.
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Affiliation(s)
- Victoria I Holden
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
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17
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Bearson BL. Molecular Profiling: Catecholamine Modulation of Gene Expression in Escherichia coli O157:H7 and Salmonella enterica Serovar Typhimurium. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 874:167-82. [DOI: 10.1007/978-3-319-20215-0_7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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18
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Chairatana P, Zheng T, Nolan EM. Targeting virulence: salmochelin modification tunes the antibacterial activity spectrum of β-lactams for pathogen-selective killing of Escherichia coli. Chem Sci 2015; 6:4458-4471. [PMID: 28717471 PMCID: PMC5499518 DOI: 10.1039/c5sc00962f] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 05/21/2015] [Indexed: 12/11/2022] Open
Abstract
New antibiotics are required to treat bacterial infections and counteract the emergence of antibiotic resistance. Pathogen-specific antibiotics have several advantages over broad-spectrum drugs, which include minimal perturbation to the commensal microbiota. We present a strategy for targeting antibiotics to bacterial pathogens that utilises the salmochelin-mediated iron uptake machinery of Gram-negative Escherichia coli. Salmochelins are C-glucosylated derivatives of the siderophore enterobactin. The biosynthesis and utilisation of salmochelins are important for virulence because these siderophores allow pathogens to acquire iron and evade the enterobactin-scavenging host-defense protein lipocalin-2. Inspired by the salmochelins, we report the design and chemoenzymatic preparation of glucosylated enterobactin-β-lactam conjugates that harbour the antibiotics ampicillin (Amp) and amoxicillin (Amx), hereafter GlcEnt-Amp/Amx. The GlcEnt scaffolds are based on mono- and diglucosylated Ent where one catechol moiety is functionalized at the C5 position for antibiotic attachment. We demonstrate that GlcEnt-Amp/Amx provide up to 1000-fold enhanced antimicrobial activity against uropathogenic E. coli relative to the parent β-lactams. Moreover, GlcEnt-Amp/Amx based on a diglucosylated Ent (DGE) platform selectively kill uropathogenic E. coli that express the salmochelin receptor IroN in the presence of non-pathogenic E. coli and other bacterial strains that include the commensal microbe Lactobacillus rhamnosus GG. Moreover, GlcEnt-Amp/Amx evade the host-defense protein lipocalin-2, and exhibit low toxicity to mammalian cells. Our work establishes that siderophore-antibiotic conjugates provide a strategy for targeting virulence, narrowing the activity spectrum of antibiotics in clinical use, and achieving selective delivery of antibacterial cargos to pathogenic bacteria on the basis of siderophore receptor expression.
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Affiliation(s)
- Phoom Chairatana
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA . ; ; Tel: +1-617-452-2495
| | - Tengfei Zheng
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA . ; ; Tel: +1-617-452-2495
| | - Elizabeth M Nolan
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA . ; ; Tel: +1-617-452-2495
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19
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Koh EI, Henderson JP. Microbial Copper-binding Siderophores at the Host-Pathogen Interface. J Biol Chem 2015; 290:18967-74. [PMID: 26055720 DOI: 10.1074/jbc.r115.644328] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Numerous pathogenic microorganisms secrete small molecule chelators called siderophores defined by their ability to bind extracellular ferric iron, making it bioavailable to microbes. Recently, a siderophore produced by uropathogenic Escherichia coli, yersiniabactin, was found to also bind copper ions during human infections. The ability of yersiniabactin to protect E. coli from copper toxicity and redox-based phagocyte defenses distinguishes it from other E. coli siderophores. Here we compare yersiniabactin to other extracellular copper-binding molecules and review how copper-binding siderophores may confer virulence-associated gains of function during infection pathogenesis.
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Affiliation(s)
- Eun-Ik Koh
- From the Center for Women's Infectious Diseases Research, Division of Infectious Diseases, and Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Jeffrey P Henderson
- From the Center for Women's Infectious Diseases Research, Division of Infectious Diseases, and Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
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20
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Caza M, Garénaux A, Lépine F, Dozois CM. Catecholate siderophore esterases Fes, IroD and IroE are required for salmochelins secretion following utilization, but only IroD contributes to virulence of extra-intestinal pathogenic Escherichia coli. Mol Microbiol 2015; 97:717-32. [PMID: 25982934 DOI: 10.1111/mmi.13059] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/13/2015] [Indexed: 01/31/2023]
Abstract
Salmochelins are glucosylated forms of enterobactin (enterochelin) and contribute to the virulence of Salmonella enterica and some extra-intestinal pathogenic Escherichia coli (ExPEC). Fes, IroD and IroE esterases degrade salmochelins and enterobactin to release iron. We investigated the apparently redundant role of these esterases in virulence and in salmochelin production and utilization of the ExPEC strain χ7122. The ΔiroD, ΔfesΔiroD and ΔfesΔiroDΔiroE mutants displayed attenuated virulence phenotypes in an avian systemic infection model. Growth of ΔfesΔiroD and ΔfesΔiroDΔiroE mutants was severely reduced in the presence of conalbumin, and although enterobactin was produced, no salmochelins were detected in the culture supernatants of these mutants. Elimination of catecholate synthesis via an entA deletion in a ΔfesΔiroDΔiroE restored growth in the presence of conalbumin, but only partially restored the virulence of the strain. Salmochelin production was reestablished by reintroducing active esterases. Intracellular accumulation of cyclic mono-glucosylated enterobactin was observed in the triple mutant ΔfesΔiroDΔiroE, and deletion of fepC, required for catecholate import into the cytoplasm, restored salmochelin detection in supernatants. These results suggest that in the absence of esterases, cyclic salmochelins are synthesized and secreted, but remain cell-bound after internalization indicating that esterase-mediated degradation is required for re-secretion of catecholate siderophore molecules following their utilization.
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Affiliation(s)
- Mélissa Caza
- INRS-Institut Armand-Frappier, Laval, Québec, Canada
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21
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Shields-Cutler RR, Crowley JR, Hung CS, Stapleton AE, Aldrich CC, Marschall J, Henderson JP. Human Urinary Composition Controls Antibacterial Activity of Siderocalin. J Biol Chem 2015; 290:15949-60. [PMID: 25861985 DOI: 10.1074/jbc.m115.645812] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Indexed: 11/06/2022] Open
Abstract
During Escherichia coli urinary tract infections, cells in the human urinary tract release the antimicrobial protein siderocalin (SCN; also known as lipocalin 2, neutrophil gelatinase-associated lipocalin/NGAL, or 24p3). SCN can interfere with E. coli iron acquisition by sequestering ferric iron complexes with enterobactin, the conserved E. coli siderophore. Here, we find that human urinary constituents can reverse this relationship, instead making enterobactin critical for overcoming SCN-mediated growth restriction. Urinary control of SCN activity exhibits wide ranging individual differences. We used these differences to identify elevated urinary pH and aryl metabolites as key biochemical host factors controlling urinary SCN activity. These aryl metabolites are well known products of intestinal microbial metabolism. Together, these results identify an innate antibacterial immune interaction that is critically dependent upon individualistic chemical features of human urine.
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Affiliation(s)
- Robin R Shields-Cutler
- From the Division of Infectious Diseases, Department of Medicine, Center for Women's Infectious Disease Research, and
| | - Jan R Crowley
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Chia S Hung
- From the Division of Infectious Diseases, Department of Medicine, Center for Women's Infectious Disease Research, and
| | - Ann E Stapleton
- the Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington 98195
| | - Courtney C Aldrich
- the Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, and
| | - Jonas Marschall
- From the Division of Infectious Diseases, Department of Medicine, the Department of Infectious Diseases, Bern University Hospital and University of Bern, 3010 Bern, Switzerland
| | - Jeffrey P Henderson
- From the Division of Infectious Diseases, Department of Medicine, Center for Women's Infectious Disease Research, and
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22
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Acyl peptidic siderophores: structures, biosyntheses and post-assembly modifications. Biometals 2015; 28:445-59. [PMID: 25677460 DOI: 10.1007/s10534-015-9827-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 01/28/2015] [Indexed: 10/24/2022]
Abstract
Acyl peptidic siderophores are produced by a variety of bacteria and possess unique amphiphilic properties. Amphiphilic siderophores are generally produced in a suite where the iron(III)-binding headgroup remains constant while the fatty acid appendage varies by length and functionality. Acyl peptidic siderophores are commonly synthesized by non-ribosomal peptide synthetases; however, the method of peptide acylation during biosynthesis can vary between siderophores. Following biosynthesis, acyl siderophores can be further modified enzymatically to produce a more hydrophilic compound, which retains its ferric chelating abilities as demonstrated by pyoverdine from Pseudomonas aeruginosa and the marinobactins from certain Marinobacter species. Siderophore hydrophobicity can also be altered through photolysis of the ferric complex of certain β-hydroxyaspartic acid-containing acyl peptidic siderophores.
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23
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Bacterial siderophores that evade or overwhelm lipocalin 2 induce hypoxia inducible factor 1α and proinflammatory cytokine secretion in cultured respiratory epithelial cells. Infect Immun 2014; 82:3826-36. [PMID: 24980968 DOI: 10.1128/iai.01849-14] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Iron is essential for many cellular processes and is required by bacteria for replication. To acquire iron from the host, pathogenic Gram-negative bacteria secrete siderophores, including enterobactin (Ent). However, Ent is bound by the host protein lipocalin 2 (Lcn2), preventing bacterial reuptake of aferric or ferric Ent. Furthermore, the combination of Ent and Lcn2 (Ent+Lcn2) leads to enhanced secretion of interleukin-8 (IL-8) compared to that induced by either stimulus alone. Modified or structurally distinct siderophores, including yersiniabactin (Ybt) and glycosylated Ent (GlyEnt, or salmochelin), deliver iron to bacteria despite the presence of Lcn2. We hypothesized that the robust immune response to Ent and Lcn2 requires iron chelation rather than the Ent+Lcn2 complex itself and also can be stimulated by Lcn2-evasive siderophores. To test this hypothesis, cultured respiratory epithelial cells were stimulated with combinations of purified siderophores and Lcn2 and analyzed by gene expression microarrays, quantitative PCR, and cytokine immunoassays. Ent caused HIF-1α protein stabilization, induced the expression of genes regulated by hypoxia-inducible factor 1α (HIF-1α), and repressed genes involved in cell cycle and DNA replication, whereas Lcn2 induced expression of proinflammatory cytokines. Iron chelation by excess Ent or Ybt significantly increased Lcn2-induced secretion of IL-8, IL-6, and CCL20. Stabilization of HIF-1α was sufficient to enhance Lcn2-induced IL-6 secretion. These data indicate that respiratory epithelial cells can respond to bacterial siderophores that evade or overwhelm Lcn2 binding by increasing proinflammatory cytokine production.
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24
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Lv H, Hung CS, Henderson JP. Metabolomic analysis of siderophore cheater mutants reveals metabolic costs of expression in uropathogenic Escherichia coli. J Proteome Res 2014; 13:1397-404. [PMID: 24476533 PMCID: PMC3993901 DOI: 10.1021/pr4009749] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
![]()
Bacterial
siderophores are a group of chemically diverse, virulence-associated
secondary metabolites whose expression exerts metabolic costs. A combined
bacterial genetic and metabolomic approach revealed differential metabolomic
impacts associated with biosynthesis of different siderophore structural
families. Despite myriad genetic differences, the metabolome of a
cheater mutant lacking a single set of siderophore biosynthetic genes
more closely approximate that of a non-pathogenic K12 strain than
its isogenic, uropathogen parent strain. Siderophore types associated
with greater metabolomic perturbations are less common among human
isolates, suggesting that metabolic costs influence success in a human
population. Although different siderophores share a common iron acquisition
function, our analysis shows how a metabolomic approach can distinguish
their relative metabolic impacts in E. coli.
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Affiliation(s)
- Haitao Lv
- Center for Women's Infectious Diseases Research, Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine , St. Louis, Missouri 63110, United States
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25
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Miethke M. Molecular strategies of microbial iron assimilation: from high-affinity complexes to cofactor assembly systems. Metallomics 2013. [DOI: 10.1039/c2mt20193c] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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26
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Interaction of lipocalin 2, transferrin, and siderophores determines the replicative niche of Klebsiella pneumoniae during pneumonia. mBio 2012; 3:mBio.00224-11. [PMID: 23169997 PMCID: PMC3509427 DOI: 10.1128/mbio.00224-11] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Pathogenic bacteria require iron for replication within their host. Klebsiella pneumoniae and other Gram-negative pathogens produce the prototypical siderophore enterobactin (Ent) to scavenge iron in vivo. In response, mucosal surfaces secrete lipocalin 2 (Lcn2), an innate immune protein that binds Ent to disrupt bacterial iron acquisition and promote acute inflammation during colonization. A subset of K. pneumoniae isolates attempt to evade Lcn2 by producing glycosylated Ent (Gly-Ent, salmochelin) or the alternative siderophore yersiniabactin (Ybt). However, these siderophores are not functionally equivalent and differ in their abilities to promote growth in the upper respiratory tract, lungs, and serum. To understand how Lcn2 exploits functional differences between siderophores, isogenic mutants of an Ent+ Gly-Ent+ Ybt+K. pneumoniae strain were inoculated into Lcn2+/+ and Lcn2−/− mice, and the pattern of pneumonia was examined. Lcn2 effectively protected against the iroA ybtS mutant (Ent+ Gly-Ent− Ybt−). Lcn2+/+ mice had small foci of pneumonia, whereas Lcn2−/− mice had many bacteria in the perivascular space. The entB mutant (Ent− Ybt+ Gly-Ent−) caused moderate bronchopneumonia but did not invade the transferrin-containing perivascular space. Accordingly, transferrin blocked Ybt-dependent growth in vitro. The wild type and the iroA mutant, which both produce Ent and Ybt, had a mixed phenotype, causing a moderate bronchopneumonia in Lcn2+/+ mice and perivascular overgrowth in Lcn2−/− mice. Together, these data indicate that Lcn2, in combination with transferrin, confines K. pneumoniae to the airways and prevents invasion into tissue containing the pulmonary vasculature. Gram-negative bacteria are a common cause of severe hospital-acquired infections. To cause disease, they must obtain iron and secrete the small molecule enterobactin to do so. Animal models of pneumonia using Klebsiella pneumoniae indicate that enterobactin promotes severe disease. Accordingly, the host defense protein lipocalin 2 exploits this common target by binding enterobactin and disrupting its function. However, pathogenic bacteria often make additional siderophores that lipocalin 2 cannot bind, such as yersiniabactin, which could make this host defense ineffective. This work compares the pattern and severity of pneumonia caused by K. pneumoniae based on which siderophores it produces. The results indicate that enterobactin promotes growth around blood vessels that are rich in the iron-binding protein transferrin, but yersiniabactin does not. Together, transferrin and lipocalin 2 protect this space against all types of K. pneumoniae tested. Therefore, the ability to acquire iron determines where bacteria can grow in the lung.
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27
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Zheng T, Bullock JL, Nolan EM. Siderophore-mediated cargo delivery to the cytoplasm of Escherichia coli and Pseudomonas aeruginosa: syntheses of monofunctionalized enterobactin scaffolds and evaluation of enterobactin-cargo conjugate uptake. J Am Chem Soc 2012; 134:18388-400. [PMID: 23098193 DOI: 10.1021/ja3077268] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The design and syntheses of monofunctionalized enterobactin (Ent, L- and D-isomers) scaffolds where one catecholate moiety of enterobactin houses an alkene, aldehyde, or carboxylic acid at the C5 position are described. These molecules are key precursors to a family of 10 enterobactin-cargo conjugates presented in this work, which were designed to probe the extent to which the Gram-negative ferric enterobactin uptake and processing machinery recognizes, transports, and utilizes derivatized enterobactin scaffolds. A series of growth recovery assays employing enterobactin-deficient E. coli ATCC 33475 (ent-) revealed that six conjugates based on L-Ent having relatively small cargos promoted E. coli growth under iron-limiting conditions whereas negligible-to-no growth recovery was observed for four conjugates with relatively large cargos. No growth recovery was observed for the enterobactin receptor-deficient strain of E. coli H1187 (fepA-) or the enterobactin esterase-deficient derivative of E. coli K-12 JW0576 (fes-), or when the D-isomer of enterobactin was employed. These results demonstrate that the E. coli ferric enterobactin transport machinery identifies and delivers select cargo-modified scaffolds to the E. coli cytoplasm. Pseudomonas aeruginosa PAO1 K648 (pvd-, pch-) exhibited greater promiscuity than that of E. coli for the uptake and utilization of the enterobactin-cargo conjugates, and growth promotion was observed for eight conjugates under iron-limiting conditions. Enterobactin may be utilized for delivering molecular cargos via its transport machinery to the cytoplasm of E. coli and P. aeruginosa thereby providing a means to overcome the Gram-negative outer membrane permeability barrier.
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Affiliation(s)
- Tengfei Zheng
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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28
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Bearson BL, Bearson SM. Host specific differences alter the requirement for certain Salmonella genes during swine colonization. Vet Microbiol 2011; 150:215-9. [DOI: 10.1016/j.vetmic.2010.12.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 12/10/2010] [Accepted: 12/21/2010] [Indexed: 12/20/2022]
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29
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Roberts AA, Ryan KS, Moore BS, Gulder TA. Total (bio)synthesis: strategies of nature and of chemists. Top Curr Chem (Cham) 2010; 297:149-203. [PMID: 21495259 PMCID: PMC3109256 DOI: 10.1007/128_2010_79] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The biosynthetic pathways to a number of natural products have been reconstituted in vitro using purified enzymes. Many of these molecules have also been synthesized by organic chemists. Here we compare the strategies used by nature and by chemists to reveal the underlying logic and success of each total synthetic approach for some exemplary molecules with diverse biosynthetic origins.
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30
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Henderson JP, Crowley JR, Pinkner JS, Walker JN, Tsukayama P, Stamm WE, Hooton TM, Hultgren SJ. Quantitative metabolomics reveals an epigenetic blueprint for iron acquisition in uropathogenic Escherichia coli. PLoS Pathog 2009; 5:e1000305. [PMID: 19229321 PMCID: PMC2637984 DOI: 10.1371/journal.ppat.1000305] [Citation(s) in RCA: 164] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Accepted: 01/20/2009] [Indexed: 11/19/2022] Open
Abstract
Bacterial pathogens are frequently distinguished by the presence of acquired genes associated with iron acquisition. The presence of specific siderophore receptor genes, however, does not reliably predict activity of the complex protein assemblies involved in synthesis and transport of these secondary metabolites. Here, we have developed a novel quantitative metabolomic approach based on stable isotope dilution to compare the complement of siderophores produced by Escherichia coli strains associated with intestinal colonization or urinary tract disease. Because uropathogenic E. coli are believed to reside in the gut microbiome prior to infection, we compared siderophore production between urinary and rectal isolates within individual patients with recurrent UTI. While all strains produced enterobactin, strong preferential expression of the siderophores yersiniabactin and salmochelin was observed among urinary strains. Conventional PCR genotyping of siderophore receptors was often insensitive to these differences. A linearized enterobactin siderophore was also identified as a product of strains with an active salmochelin gene cluster. These findings argue that qualitative and quantitative epi-genetic optimization occurs in the E. coli secondary metabolome among human uropathogens. Because the virulence-associated biosynthetic pathways are distinct from those associated with rectal colonization, these results suggest strategies for virulence-targeted therapies. Urinary tract infections (UTIs) are among the most common bacterial infections treated by physicians worldwide. Although symptoms of acute infection are often resolved with a course of antibiotics, the same bacterial strain often causes subsequent bouts of symptomatic infection. Escherichia coli are the most common bacteria causing UTI and the infecting strains are widely believed to originate from the gastrointestinal tract where multiple E. coli strains reside. Here, we use a novel mass spectrometric technique in a population of patients with recurrent UTI to identify how strains that cause UTI differ from other strains that were present in the gastrointestinal tract at the same time. We found that urinary E. coli strains preferentially expressed two small molecules called yersiniabactin and salmochelin. These molecules are called siderophores, meaning they are able to scavenge iron to support bacterial survival and growth. Synthesis and transport of these small molecules requires a coordinated network of proteins encoded by a collection of different genes. These findings suggest that new antibiotics directed against yersiniabactin or salmochelin-producing E. coli strains may be an improved, and more targeted, strategy to prevent recurrent UTIs.
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Affiliation(s)
- Jeffrey P. Henderson
- Center for Women's Infectious Diseases Research, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Division of Infectious Diseases, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Jan R. Crowley
- Division of Infectious Diseases, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Jerome S. Pinkner
- Center for Women's Infectious Diseases Research, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Jennifer N. Walker
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Pablo Tsukayama
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Walter E. Stamm
- Department of Internal Medicine, University of Washington, Seattle, Washington, United States of America
| | - Thomas M. Hooton
- Department of Internal Medicine, University of Miami, Miami, Florida, United States of America
| | - Scott J. Hultgren
- Center for Women's Infectious Diseases Research, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- * E-mail:
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31
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Crouch MLV, Castor M, Karlinsey JE, Kalhorn T, Fang FC. Biosynthesis and IroC-dependent export of the siderophore salmochelin are essential for virulence of Salmonella enterica serovar Typhimurium. Mol Microbiol 2007; 67:971-83. [PMID: 18194158 DOI: 10.1111/j.1365-2958.2007.06089.x] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In response to iron deprivation, Salmonella enterica serovar Typhimurium secretes two catecholate-type siderophores, enterobactin and its glucosylated derivative salmochelin. Although the systems responsible for enterobactin synthesis and acquisition are well characterized, the mechanisms of salmochelin secretion and acquisition, as well as its role in Salmonella virulence, are incompletely understood. Herein we show by liquid chromatography-mass spectrometry analysis of culture supernatants from wild type and isogenic mutant bacterial strains that the Major Facilitator Superfamily pump EntS is the major exporter of enterobactin and the ABC transporter IroC exports both salmochelin and enterobactin. Growth promotion experiments demonstrate that IroC is not required for utilization of Fe-enterobactin or Fe-salmochelin, as had been previously suggested, but the ABC transporter protein FepD is required for utilization of both siderophores. Salmonella mutants deficient in salmochelin synthesis or secretion exhibit reduced virulence during systemic infection of mice.
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Affiliation(s)
- Marie-Laure V Crouch
- Department of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA
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32
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Nolan EM, Fischbach MA, Koglin A, Walsh CT. Biosynthetic tailoring of microcin E492m: post-translational modification affords an antibacterial siderophore-peptide conjugate. J Am Chem Soc 2007; 129:14336-47. [PMID: 17973380 PMCID: PMC2522288 DOI: 10.1021/ja074650f] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The present work reveals that four proteins, MceCDIJ, encoded by the MccE492 gene cluster are responsible for the remarkable post-translational tailoring of microcin E492 (MccE492), an 84-residue protein toxin secreted by Klebsiella pneumonaie RYC492 that targets neighboring Gram-negative species. This modification results in attachment of a linearized and monoglycosylated derivative of enterobactin, a nonribosomal peptide and iron scavenger (siderophore), to the MccE492m C-terminus. MceC and MceD derivatize enterobactin by C-glycosylation at the C5 position of a N-(2,3-dihydroxybenzoyl)serine (DHB-Ser) moiety and regiospecific hydrolysis of an ester linkage in the trilactone scaffold, respectively. MceI and MceJ form a protein complex that attaches C-glycosylated enterobactins to the C-terminal serine residue of both a C10 model peptide and full-length MccE492. In the enzymatic product, the C-terminal serine residue is covalently attached to the C4' oxygen of the glucose moiety. Nonenzymatic and base-catalyzed migration of the peptide to the C6' position affords the C6' glycosyl ester linkage observed in the mature toxin, MccE492m, isolated from bacterial cultures.
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Affiliation(s)
- Elizabeth M. Nolan
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
| | - Michael A. Fischbach
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
| | - Alexander Koglin
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
| | - Christopher T. Walsh
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
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Abstract
High-affinity iron acquisition is mediated by siderophore-dependent pathways in the majority of pathogenic and nonpathogenic bacteria and fungi. Considerable progress has been made in characterizing and understanding mechanisms of siderophore synthesis, secretion, iron scavenging, and siderophore-delivered iron uptake and its release. The regulation of siderophore pathways reveals multilayer networks at the transcriptional and posttranscriptional levels. Due to the key role of many siderophores during virulence, coevolution led to sophisticated strategies of siderophore neutralization by mammals and (re)utilization by bacterial pathogens. Surprisingly, hosts also developed essential siderophore-based iron delivery and cell conversion pathways, which are of interest for diagnostic and therapeutic studies. In the last decades, natural and synthetic compounds have gained attention as potential therapeutics for iron-dependent treatment of infections and further diseases. Promising results for pathogen inhibition were obtained with various siderophore-antibiotic conjugates acting as "Trojan horse" toxins and siderophore pathway inhibitors. In this article, general aspects of siderophore-mediated iron acquisition, recent findings regarding iron-related pathogen-host interactions, and current strategies for iron-dependent pathogen control will be reviewed. Further concepts including the inhibition of novel siderophore pathway targets are discussed.
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Affiliation(s)
- Marcus Miethke
- Philipps Universität Marburg, FB Chemie Biochemie, Hans Meerwein Strasse, D-35032 Marburg, Germany
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Abergel RJ, Warner JA, Shuh DK, Raymond KN. Enterobactin protonation and iron release: structural characterization of the salicylate coordination shift in ferric enterobactin. J Am Chem Soc 2007; 128:8920-31. [PMID: 16819888 PMCID: PMC3188320 DOI: 10.1021/ja062046j] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The siderophore enterobactin (Ent) is produced by many species of enteric bacteria to mediate iron uptake. This iron scavenger can be reincorporated by the bacteria as the ferric complex [Fe(III)(Ent)](3)(-) and is subsequently hydrolyzed by an esterase to facilitate intracellular iron release. Recent literature reports on altered protein recognition and binding of modified enterobactin increase the significance of understanding the structural features and solution chemistry of ferric enterobactin. The structure of the neutral protonated ferric enterobactin complex [Fe(III)(H(3)Ent)](0) has been the source of some controversy and confusion in the literature. To demonstrate the proposed change of coordination from the tris-catecholate [Fe(III)(Ent)](3)(-) to the tris-salicylate [Fe(III)(H(3)Ent)](0) upon protonation, the coordination chemistry of two new model compounds N,N',N''-tris[2-(hydroxybenzoyl)carbonyl]cyclotriseryl trilactone (SERSAM) and N,N',N''-tris[2-hydroxy,3-methoxy(benzoyl)carbonyl]cyclotriseryl trilactone (SER(3M)SAM) was examined in solution and solid state. Both SERSAM and SER(3M)SAM form tris-salicylate ferric complexes with spectroscopic and solution thermodynamic properties (with log beta(110)() values of 39 and 38 respectively) similar to those of [Fe(III)(H(3)Ent)](0). The fits of EXAFS spectra of the model ferric complexes and the two forms of ferric enterobactin provided bond distances and disorder factors in the metal coordination sphere for both coordination modes. The protonated [Fe(III)(H(3)Ent)](0) complex (d(Fe)(-)(O) = 1.98 A, sigma(2)(stat)(O) = 0.00351(10) A(2)) exhibits a shorter average Fe-O bond length but a much higher static Debye-Waller factor for the first oxygen shell than the catecholate [Fe(III)(Ent)](3)(-) complex (d(Fe)(-)(O) = 2.00 A, sigma(2)(stat)(O) = 0.00067(14) A(2)). (1)H NMR spectroscopy was used to monitor the amide bond rotation between the catecholate and salicylate geometries using the gallic complexes of enterobactin: [Ga(III)(Ent)](3)(-) and [Ga(III)(H(3)Ent)](0). The ferric salicylate complexes display quasi-reversible reduction potentials from -89 to -551 mV (relative to the normal hydrogen electrode NHE) which supports the feasibility of a low pH iron release mechanism facilitated by biological reductants.
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Affiliation(s)
- Rebecca J. Abergel
- Contribution from the Department of Chemistry, University of California, Berkeley, CA 94720-1460
| | - Jeffrey A. Warner
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - David K. Shuh
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Kenneth N. Raymond
- Contribution from the Department of Chemistry, University of California, Berkeley, CA 94720-1460
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
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35
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Martinez JS, Butler A. Marine amphiphilic siderophores: marinobactin structure, uptake, and microbial partitioning. J Inorg Biochem 2007; 101:1692-8. [PMID: 17868890 PMCID: PMC3061822 DOI: 10.1016/j.jinorgbio.2007.07.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2007] [Revised: 06/18/2007] [Accepted: 07/06/2007] [Indexed: 11/22/2022]
Abstract
Marinobactins A-E are a suite of amphiphilic siderophores which have a common peptidic head group that coordinates Fe(III), and a fatty acid which varies in length and saturation. As a result of the amphiphilic properties of these siderophores it is difficult to study siderophore-mediated uptake of iron, because the amphiphilic siderophores partition indiscriminately in microbial and other membranes. An alternative method to distinguish amphiphilic siderophore partitioning versus siderophore-mediated active uptake for Fe(III)-marinobactin E has been developed. In addition, a new member of the marinobactin family of siderophores is also reported, marinobactin F, which has a C(18) fatty acid with one double bond and which is substantially more hydrophobic that marinobactins A-E.
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Affiliation(s)
| | - Alison Butler
- To whom correspondence should be addressed: , FAX: (805) 893-4120
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36
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Rodriguez GM, Gardner R, Kaur N, Phanstiel O. Utilization of Fe3+-acinetoferrin analogs as an iron source by Mycobacterium tuberculosis. Biometals 2007; 21:93-103. [PMID: 17401548 DOI: 10.1007/s10534-007-9096-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Accepted: 03/05/2007] [Indexed: 10/23/2022]
Abstract
Mycobacterium tuberculosis, the causative agent of human tuberculosis, synthesizes and secretes siderophores in order to compete for iron (an essential micronutrient). Successful iron acquisition allows M. tuberculosis to survive and proliferate under the iron-deficient conditions encountered in the host. To examine structural determinants important for iron siderophore transport in this pathogen, the citrate-based siderophores petrobactin, acinetoferrin and various acinetoferrin homologs were synthesized and used as iron transport probes. Mutant strains of M. tuberculosis deficient in native siderophore synthesis or transport were utilized to better understand the mechanisms involved in iron delivery via the synthetic siderophores. Acinetoferrin and its derivatives, especially those containing a cyclic imide group, were able to deliver iron or gallium into M. tuberculosis which promoted or inhibited, respectively, the growth of this pathogen.
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Affiliation(s)
- G Marcela Rodriguez
- The Public Health Research Institute at the International Center for Public Health, University of Medicine and Dentistry of New Jersey, 225 Warren Street, Newark, NJ 07103-3535, USA.
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Fischbach MA, Lin H, Zhou L, Yu Y, Abergel RJ, Liu DR, Raymond KN, Wanner BL, Strong RK, Walsh CT, Aderem A, Smith KD. The pathogen-associated iroA gene cluster mediates bacterial evasion of lipocalin 2. Proc Natl Acad Sci U S A 2006; 103:16502-7. [PMID: 17060628 PMCID: PMC1637611 DOI: 10.1073/pnas.0604636103] [Citation(s) in RCA: 232] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Numerous bacteria cope with the scarcity of iron in their microenvironment by synthesizing small iron-scavenging molecules known as siderophores. Mammals have evolved countermeasures to block siderophore-mediated iron acquisition as part of their innate immune response. Secreted lipocalin 2 (Lcn2) sequesters the Escherichia coli siderophore enterobactin (Ent), preventing E. coli from acquiring iron and protecting mammals from infection by E. coli. Here, we show that the iroA gene cluster, found in many pathogenic strains of Gram-negative enteric bacteria, including E. coli, Salmonella spp., and Klebsiella pneumoniae, allows bacteria to evade sequestration of Ent by Lcn2. We demonstrate that C-glucosylated derivatives of Ent produced by iroA-encoded enzymes do not bind purified Lcn2, and an iroA-harboring strain of E. coli is insensitive to the growth inhibitory effects of Lcn2 in vitro. Furthermore, we show that mice rapidly succumb to infection by an iroA-harboring strain of E. coli but not its wild-type counterpart, and that this increased virulence depends on evasion of host Lcn2. Our findings indicate that the iroA gene cluster allows bacteria to evade this component of the innate immune system, rejuvenating their Ent-mediated iron-acquisition pathway and playing an important role in their virulence.
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Affiliation(s)
- Michael A. Fischbach
- *Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
- Howard Hughes Medical Institute and Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
| | - Hening Lin
- *Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
| | - Lu Zhou
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907
| | - Yang Yu
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907
| | | | - David R. Liu
- Howard Hughes Medical Institute and Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
| | | | - Barry L. Wanner
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907
| | - Roland K. Strong
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109
| | - Christopher T. Walsh
- *Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
| | - Alan Aderem
- Institute for Systems Biology, Seattle, WA 98103; and
| | - Kelly D. Smith
- **Department of Pathology, University of Washington, Seattle, WA 98195
- To whom correspondence should be addressed. E-mail:
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38
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Lin H, Fischbach MA, Gatto GJ, Liu DR, Walsh CT. Bromoenterobactins as Potent Inhibitors of a Pathogen-Associated, Siderophore-Modifying C-Glycosyltransferase. J Am Chem Soc 2006; 128:9324-5. [PMID: 16848455 DOI: 10.1021/ja063236x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
IroB is a C-glycosyltransferase encoded in the iroA cluster. C-Glucosylation of the bacterial siderophore enterobactin by IroB is a strategy some pathogenic bacteria use to evade the host's innate immunity mediated by lipocalin 2 (Lcn2). Without this modification, enterobactin can be tightly bound by host Lcn2, rendering it ineffective as a siderophore. Therefore, IroB inhibitors could be potential antibiotics against iroA-harboring pathogenic bacteria. We used enterobactin analogues to probe the properties of the active site of IroB and found that enterobactin analogues brominated at the C5 positions of the 2,3-dihydroxybenzoyl rings are potent inhibitors of IroB. This finding could lead to the discovery of effective antibiotics targeting iroA-containing bacteria.
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Affiliation(s)
- Hening Lin
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
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