1
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Torres-Escobar A, Wilkins A, Juárez-Rodríguez MD, Circu M, Latimer B, Dragoi AM, Ivanov SS. Iron-depleting nutritional immunity controls extracellular bacterial replication in Legionella pneumophila infections. Nat Commun 2024; 15:7848. [PMID: 39245746 PMCID: PMC11381550 DOI: 10.1038/s41467-024-52184-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 08/29/2024] [Indexed: 09/10/2024] Open
Abstract
The accidental human pathogen Legionella pneumophila (Lp) is the etiological agent for a severe atypical pneumonia known as Legionnaires' disease. In human infections and animal models of disease alveolar macrophages are the primary cellular niche that supports bacterial replication within a unique intracellular membrane-bound organelle. The Dot/Icm apparatus-a type IV secretion system that translocates ~300 bacterial proteins within the cytosol of the infected cell-is a central virulence factor required for intracellular growth. Mutant strains lacking functional Dot/Icm apparatus are transported to and degraded within the lysosomes of infected macrophages. The early foundational work from Dr. Horwitz's group unequivocally established that Legionella does not replicate extracellularly during infection-a phenomenon well supported by experimental evidence for four decades. Our data challenges this paradigm by demonstrating that macrophages and monocytes provide the necessary nutrients and support robust Legionella extracellular replication. We show that the previously reported lack of Lp extracellular replication is not a bacteria intrinsic feature but rather a result of robust restriction by serum-derived nutritional immunity factors. Specifically, the host iron-sequestering protein Transferrin is identified here as a critical suppressor of Lp extracellular replication in an iron-dependent manner. In iron-overload conditions or in the absence of Transferrin, Lp bypasses growth restriction by IFNγ-primed macrophages though extracellular replication. It is well established that certain risk factors associated with development of Legionnaires' disease, such as smoking, produce a chronic pulmonary environment of iron-overload. Our work indicates that iron-overload could be an important determinant of severe infection by allowing Lp to overcome nutritional immunity and replicate extracellularly, which in turn would circumvent intracellular cell intrinsic host defenses. Thus, we provide evidence for nutritional immunity as a key underappreciated host defense mechanism in Legionella pathogenesis.
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Affiliation(s)
- Ascención Torres-Escobar
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA, 71130, USA
| | - Ashley Wilkins
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA, 71130, USA
- Bacterial Physiology and Metabolism Unit, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA
| | - María D Juárez-Rodríguez
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA, 71130, USA
| | - Magdalena Circu
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA, 71130, USA
| | - Brian Latimer
- Innovative North Louisiana Experimental Therapeutics program (INLET), Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA, 71130, USA
| | - Ana-Maria Dragoi
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA, 71130, USA
- Innovative North Louisiana Experimental Therapeutics program (INLET), Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA, 71130, USA
| | - Stanimir S Ivanov
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA, 71130, USA.
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2
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Hernandez JA, Micus PS, Sunga SAL, Mazzei L, Ciurli S, Meloni G. Metal selectivity and translocation mechanism characterization in proteoliposomes of the transmembrane NiCoT transporter NixA from Helicobacter pylori. Chem Sci 2024; 15:651-665. [PMID: 38179545 PMCID: PMC10762997 DOI: 10.1039/d3sc05135h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 11/29/2023] [Indexed: 01/06/2024] Open
Abstract
Essential trace metals play key roles in the survival, replication, and virulence of bacterial pathogens. Helicobacter pylori (H. pylori), the main bacterial cause of gastric ulcers, requires Ni(ii) to colonize and persist in the acidic environment inside the stomach, exploiting the nickel-containing enzyme urease to catalyze the hydrolysis of urea to ammonia and bicarbonate and create a pH-buffered microenvironment. Urease utilizes Ni(ii) as a catalytic cofactor for its activity. In ureolytic bacteria, unique transmembrane (TM) transporters evolved to guarantee the selective uptake and efflux of Ni(ii) across cellular membranes to meet the cellular requirements. NixA is an essential Ni(ii) transporter expressed by H. pylori when the extracellular environment experiences a drop in pH. This Class I nickel-cobalt transporter of the NiCoT family catalyzes the uptake of Ni(ii) across the inner membrane from the periplasm. In this study, we characterized NixA using a platform whereby, for the first time on a NiCoT transporter, recombinantly expressed and purified NixA and key mutants in the translocation pathway have been reconstituted in artificial lipid bilayer vesicles (proteoliposomes). Fluorescent sensors responsive to Ni(ii) transport (Fluozin-3-Zn(ii)), luminal pH changes (pyranine), and membrane potential (oxonol VI) were encapsulated in the proteoliposomes lumen to monitor, in real-time, NixA transport properties and translocation mechanism. Kinetic transport analysis revealed that NixA is highly selective for Ni(ii) with no substrate promiscuity towards Co(ii), the other putative metal substrate of the NiCoT family, nor Zn(ii). NixA-mediated Ni(ii) transport exhibited a Michaelis-Menten-type saturable substrate concentration dependence, with an experimental KM, Ni(ii) = 31.0 ± 1.2 μM. Ni(ii) transport by NixA was demonstrated to be electrogenic, and metal translocation did not require a proton motive force, resulting in the generation of a positive-inside transmembrane potential in the proteoliposome lumen. Mutation analysis characterized key transmembrane residues for substrate recognition, binding, and/or transport, suggesting the presence of a three-step transmembrane translocation conduit. Taken together, these investigations reveal that NixA is a Ni(ii)-selective Class I NiCoT electrogenic uniporter. The work also provides an in vitro approach to characterize the transport properties of metal transporters responsible for Ni(ii) acquisition and extrusion in prokaryotes.
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Affiliation(s)
- Jayoh A Hernandez
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
| | - Paul S Micus
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
| | - Sean Alec Lois Sunga
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
| | - Luca Mazzei
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna Bologna I-40127 Italy
| | - Stefano Ciurli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna Bologna I-40127 Italy
| | - Gabriele Meloni
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
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3
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Pope MA, Curtis RM, Gull H, Horadigala Gamage MA, Abeyrathna SS, Abeyrathna NS, Fahrni CJ, Meloni G. Fluorescence-Based Proteoliposome Methods to Monitor Redox-Active Transition Metal Transmembrane Translocation by Metal Transporters. Methods Mol Biol 2024; 2839:77-97. [PMID: 39008249 PMCID: PMC11411439 DOI: 10.1007/978-1-0716-4043-2_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Transmembrane transition metal transporter proteins are central gatekeepers in selectively controlling vectorial metal cargo uptake and extrusion across cellular membranes in all living organisms, thus playing key roles in essential and toxic metal homeostasis. Biochemical characterization of transporter-mediated translocation events and transport kinetics of redox-active metals, such as iron and copper, is challenged by the complexity in generating reconstituted systems in which vectorial metal transport can be studied in real time. We present fluorescence-based proteoliposome methods to monitor redox-active metal transmembrane translocation upon reconstitution of purified metal transporters in artificial lipid bilayers. By encapsulating turn-on/-off iron or copper-dependent sensors in the proteoliposome lumen and conducting real-time transport assays using small unilamellar vesicles (SUVs), in which selected purified Fe(II) and Cu(I) transmembrane importer and exporter proteins have been reconstituted, we provide a platform to monitor metal translocation events across lipid bilayers in real time. The strategy is modular and expandable toward the study of different transporter families featuring diverse metal substrate selectivity and promiscuity.
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Affiliation(s)
- Mitchell A Pope
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Rose M Curtis
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Humera Gull
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | | | - Sameera S Abeyrathna
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Nisansala S Abeyrathna
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Christoph J Fahrni
- Petit Institute for Bioengineering and Bioscience, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA
| | - Gabriele Meloni
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA.
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4
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Orzel B, Pelucelli A, Ostrowska M, Potocki S, Kozlowski H, Peana M, Gumienna-Kontecka E. Fe(II), Mn(II), and Zn(II) Binding to the C-Terminal Region of FeoB Protein: An Insight into the Coordination Chemistry and Specificity of the Escherichia coli Fe(II) Transporter. Inorg Chem 2023; 62:18607-18624. [PMID: 37910812 PMCID: PMC10647171 DOI: 10.1021/acs.inorgchem.3c02910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/03/2023] [Accepted: 10/03/2023] [Indexed: 11/03/2023]
Abstract
The interactions between two peptide ligands [Ac763CCAASTTGDCH773 (P1) and Ac743RRARSRVDIELLATRKSVSSCCAASTTGDCH773 (P2)] derived from the cytoplasmic C-terminal region of Eschericha coli FeoB protein and Fe(II), Mn(II), and Zn(II) ions were investigated. The Feo system is regarded as the most important bacterial Fe(II) acquisition system, being one of the key virulence factors, especially in anaerobic conditions. Located in the inner membrane of Gram-negative bacteria, FeoB protein transports Fe(II) from the periplasm to the cytoplasm. Despite its crucial role in bacterial pathogenicity, the mechanism in which the metal ion is trafficked through the membrane is not yet elucidated. In the gammaproteobacteria class, the cytoplasmic C-terminal part of FeoB contains conserved cysteine, histidine, and glutamic and aspartic acid residues, which could play a vital role in Fe(II) binding in the cytoplasm, receiving the metal ion from the transmembrane helices. In this work, we characterized the complexes formed between the whole cytosolic C-terminal sequence of E. coli FeoB (P2) and its key polycysteine region (P1) with Fe(II), Mn(II), and Zn(II) ions, exploring the specificity of the C-terminal region of FeoB. With the help of a variety of potentiometric, spectroscopic (electron paramagnetic resonance and NMR), and spectrometric (electrospray ionization mass spectrometry) techniques and molecular dynamics, we propose the metal-binding modes of the ligands, compare their affinities toward the metal ions, and discuss the possible physiological role of the C-terminal region of E. coli FeoB.
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Affiliation(s)
- Bartosz Orzel
- Faculty
of Chemistry, University of Wrocław, 50-383 Wrocław, Poland
| | - Alessio Pelucelli
- Department
of Chemical, Physical, Mathematical and Natural Sciences, University of Sassari, 07100 Sassari, Italy
| | | | - Slawomir Potocki
- Faculty
of Chemistry, University of Wrocław, 50-383 Wrocław, Poland
| | - Henryk Kozlowski
- Faculty
of Chemistry, University of Wrocław, 50-383 Wrocław, Poland
- Department
of Health Sciences, University of Opole, Katowicka 68, 45-060 Opole, Poland
| | - Massimiliano Peana
- Department
of Chemical, Physical, Mathematical and Natural Sciences, University of Sassari, 07100 Sassari, Italy
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5
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Lopez AE, Grigoryeva LS, Barajas A, Cianciotto NP. Legionella pneumophila Rhizoferrin Promotes Bacterial Biofilm Formation and Growth within Amoebae and Macrophages. Infect Immun 2023; 91:e0007223. [PMID: 37428036 PMCID: PMC10429650 DOI: 10.1128/iai.00072-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 06/20/2023] [Indexed: 07/11/2023] Open
Abstract
Previously, we showed that Legionella pneumophila secretes rhizoferrin, a polycarboxylate siderophore that promotes bacterial growth in iron-deplete media and the murine lung. Yet, past studies failed to identify a role for the rhizoferrin biosynthetic gene (lbtA) in L. pneumophila infection of host cells, suggesting the siderophore's importance was solely linked to extracellular survival. To test the possibility that rhizoferrin's relevance to intracellular infection was missed due to functional redundancy with the ferrous iron transport (FeoB) pathway, we characterized a new mutant lacking both lbtA and feoB. This mutant was highly impaired for growth on bacteriological media that were only modestly depleted of iron, confirming that rhizoferrin-mediated ferric iron uptake and FeoB-mediated ferrous iron uptake are critical for iron acquisition. The lbtA feoB mutant, but not its lbtA-containing complement, was also highly defective for biofilm formation on plastic surfaces, demonstrating a new role for the L. pneumophila siderophore in extracellular survival. Finally, the lbtA feoB mutant, but not its complement containing lbtA, proved to be greatly impaired for growth in Acanthamoeba castellanii, Vermamoeba vermiformis, and human U937 cell macrophages, revealing that rhizoferrin does promote intracellular infection by L. pneumophila. Moreover, the application of purified rhizoferrin triggered cytokine production from the U937 cells. Rhizoferrin-associated genes were fully conserved across the many sequenced strains of L. pneumophila examined but were variably present among strains from the other species of Legionella. Outside of Legionella, the closest match to the L. pneumophila rhizoferrin genes was in Aquicella siphonis, another facultative intracellular parasite of amoebae.
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Affiliation(s)
- Alberto E. Lopez
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois, USA
| | - Lubov S. Grigoryeva
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois, USA
| | - Armando Barajas
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois, USA
| | - Nicholas P. Cianciotto
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois, USA
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6
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Abeyrathna SS, Abeyrathna NS, Basak P, Irvine GW, Zhang L, Meloni G. Plastic recognition and electrogenic uniport translocation of 1 st-, 2 nd-, and 3 rd-row transition and post-transition metals by primary-active transmembrane P 1B-2-type ATPase pumps. Chem Sci 2023; 14:6059-6078. [PMID: 37293658 PMCID: PMC10246665 DOI: 10.1039/d3sc00347g] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 05/10/2023] [Indexed: 06/10/2023] Open
Abstract
Transmembrane P1B-type ATPase pumps catalyze the extrusion of transition metal ions across cellular lipid membranes to maintain essential cellular metal homeostasis and detoxify toxic metals. Zn(ii)-pumps of the P1B-2-type subclass, in addition to Zn2+, select diverse metals (Pb2+, Cd2+ and Hg2+) at their transmembrane binding site and feature promiscuous metal-dependent ATP hydrolysis in the presence of these metals. Yet, a comprehensive understanding of the transport of these metals, their relative translocation rates, and transport mechanism remain elusive. We developed a platform for the characterization of primary-active Zn(ii)-pumps in proteoliposomes to study metal selectivity, translocation events and transport mechanism in real-time, employing a "multi-probe" approach with fluorescent sensors responsive to diverse stimuli (metals, pH and membrane potential). Together with atomic-resolution investigation of cargo selection by X-ray absorption spectroscopy (XAS), we demonstrate that Zn(ii)-pumps are electrogenic uniporters that preserve the transport mechanism with 1st-, 2nd- and 3rd-row transition metal substrates. Promiscuous coordination plasticity, guarantees diverse, yet defined, cargo selectivity coupled to their translocation.
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Affiliation(s)
- Sameera S Abeyrathna
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
| | - Nisansala S Abeyrathna
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
| | - Priyanka Basak
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
| | - Gordon W Irvine
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
| | - Limei Zhang
- Department of Biochemistry and Redox Biology Center and the Nebraska Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln Lincoln NE 68588 USA
| | - Gabriele Meloni
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
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7
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Kumari S, Wijesundara YH, Howlett TS, Waliullah M, Herbert FC, Raja A, Trashi I, Bernal RA, Gassensmith JJ. Biolistic delivery of liposomes protected in metal-organic frameworks. Proc Natl Acad Sci U S A 2023; 120:e2218247120. [PMID: 36877851 PMCID: PMC10089211 DOI: 10.1073/pnas.2218247120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 02/03/2023] [Indexed: 03/08/2023] Open
Abstract
Needle-and-syringe-based delivery has been the commercial standard for vaccine administration to date. With worsening medical personnel availability, increasing biohazard waste production, and the possibility of cross-contamination, we explore the possibility of biolistic delivery as an alternate skin-based delivery route. Delicate formulations like liposomes are inherently unsuitable for this delivery model as they are fragile biomaterials incapable of withstanding shear stress and are exceedingly difficult to formulate as a lyophilized powder for room temperature storage. Here we have developed a approach to deliver liposomes into the skin biolistically-by encapsulating them in a nano-sized shell made of Zeolitic Imidazolate Framework-8 (ZIF-8). When encapsulated within a crystalline and rigid coating, the liposomes are not only protected from thermal stress, but also shear stress. This protection from stressors is crucial, especially for formulations with cargo encapsulated inside the lumen of the liposomes. Moreover, the coating provides the liposomes with a solid exterior that allows the particles to penetrate the skin effectively. In this work, we explored the mechanical protection ZIF-8 provides to liposomes as a preliminary investigation for using biolistic delivery as an alternative to syringe-and-needle-based delivery of vaccines. We demonstrated that liposomes with a variety of surface charges could be coated with ZIF-8 using the right conditions, and this coating can be just as easily removed-without causing any damage to the protected material. The protective coating prevented the liposomes from leaking cargo and helped in their effective penetration when delivered into the agarose tissue model and porcine skin tissue.
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Affiliation(s)
- Sneha Kumari
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX75080-3021
| | - Yalini H. Wijesundara
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX75080-3021
| | - Thomas S. Howlett
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX75080-3021
| | - Mohammad Waliullah
- Department of Mechanical Engineering, University of Texas at Dallas, Richardson, TX75080-3021
| | - Fabian C. Herbert
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX75080-3021
| | - Arun Raja
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX75080-3021
| | - Ikeda Trashi
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX75080-3021
| | - Rodrigo A. Bernal
- Department of Mechanical Engineering, University of Texas at Dallas, Richardson, TX75080-3021
| | - Jeremiah J. Gassensmith
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX75080-3021
- Department of Biomedical Engineering, University of Texas at Dallas, Richardson, TX75080-3021
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8
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Lockwood DC, Amin H, Costa TRD, Schroeder GN. The Legionella pneumophila Dot/Icm type IV secretion system and its effectors. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35639581 DOI: 10.1099/mic.0.001187] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
To prevail in the interaction with eukaryotic hosts, many bacterial pathogens use protein secretion systems to release virulence factors at the host–pathogen interface and/or deliver them directly into host cells. An outstanding example of the complexity and sophistication of secretion systems and the diversity of their protein substrates, effectors, is the Defective in organelle trafficking/Intracellular multiplication (Dot/Icm) Type IVB secretion system (T4BSS) of
Legionella pneumophila
and related species.
Legionella
species are facultative intracellular pathogens of environmental protozoa and opportunistic human respiratory pathogens. The Dot/Icm T4BSS translocates an exceptionally large number of effectors, more than 300 per
L. pneumophila
strain, and is essential for evasion of phagolysosomal degradation and exploitation of protozoa and human macrophages as replicative niches. Recent technological advancements in the imaging of large protein complexes have provided new insight into the architecture of the T4BSS and allowed us to propose models for the transport mechanism. At the same time, significant progress has been made in assigning functions to about a third of
L. pneumophila
effectors, discovering unprecedented new enzymatic activities and concepts of host subversion. In this review, we describe the current knowledge of the workings of the Dot/Icm T4BSS machinery and provide an overview of the activities and functions of the to-date characterized effectors in the interaction of
L. pneumophila
with host cells.
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Affiliation(s)
- Daniel C Lockwood
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, BT9 7BL, Northern Ireland, UK
| | - Himani Amin
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
| | - Tiago R D Costa
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
| | - Gunnar N Schroeder
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, BT9 7BL, Northern Ireland, UK
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9
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Brown JB, Lee MA, Smith AT. Ins and Outs: Recent Advancements in Membrane Protein-Mediated Prokaryotic Ferrous Iron Transport. Biochemistry 2021; 60:3277-3291. [PMID: 34670078 DOI: 10.1021/acs.biochem.1c00586] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Iron is an essential nutrient for virtually every living organism, especially pathogenic prokaryotes. Despite its importance, however, both the acquisition and the export of this element require dedicated pathways that are dependent on oxidation state. Due to its solubility and kinetic lability, reduced ferrous iron (Fe2+) is useful to bacteria for import, chaperoning, and efflux. Once imported, ferrous iron may be loaded into apo and nascent enzymes and even sequestered into storage proteins under certain conditions. However, excess labile ferrous iron can impart toxicity as it may spuriously catalyze Fenton chemistry, thereby generating reactive oxygen species and leading to cellular damage. In response, it is becoming increasingly evident that bacteria have evolved Fe2+ efflux pumps to deal with conditions of ferrous iron excess and to prevent intracellular oxidative stress. In this work, we highlight recent structural and mechanistic advancements in our understanding of prokaryotic ferrous iron import and export systems, with a focus on the connection of these essential transport systems to pathogenesis. Given the connection of these pathways to the virulence of many increasingly antibiotic resistant bacterial strains, a greater understanding of the mechanistic details of ferrous iron cycling in pathogens could illuminate new pathways for future therapeutic developments.
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Affiliation(s)
- Janae B Brown
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, Baltimore, Maryland 21250, United States
| | - Mark A Lee
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, Baltimore, Maryland 21250, United States
| | - Aaron T Smith
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, Baltimore, Maryland 21250, United States
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10
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Abeyrathna N, Abeyrathna S, Morgan MT, Fahrni CJ, Meloni G. Transmembrane Cu(I) P-type ATPase pumps are electrogenic uniporters. Dalton Trans 2021; 49:16082-16094. [PMID: 32469032 DOI: 10.1039/d0dt01380c] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Cu(i) P-type ATPases are transmembrane primary active ion pumps that catalyze the extrusion of copper ions across cellular membranes. Their activity is critical in controlling copper levels in all kingdoms of life. Biochemical and structural characterization established the structural framework by which Cu-pumps perform their function. However, the details of the overall mechanism of transport (uniporter vs. cotransporter) and electrogenicity still remain elusive. In this work, we developed a platform to reconstitute the model Cu(i)-pump from E. coli (EcCopA) in artificial lipid bilayer small unilamellar vesicles (SUVs) to quantitatively characterize the metal substrate, putative counter-ions and charge translocation. By encapsulating in the liposome lumen fluorescence detector probes (CTAP-3, pyranine and oxonol VI) responsive to diverse stimuli (Cu(i), pH and membrane potential), we correlated substrate, secondary-ion translocation and charge movement events in EcCopA proteoliposomes. This platform centered on multiple fluorescence reporters allowed study of the mechanism and translocation kinetic parameters in real-time for wild-type EcCopA and inactive mutants. The maximal initial Cu(i) transport rate of 165 nmol Cu(i) mg-1 min-1 and KM, Cu(I) = 0.15 ± 0.07 μM was determined with this analysis. We reveal that Cu(i) pumps are primary-active uniporters and electrogenic. The Cu(i) translocation cycle does not require proton counter-transport resulting in electrogenic generation of transmembrane potential upon translocation of one Cu(i) per ATP hydrolysis cycle. Thus, mechanistic differences between Cu(i) pumps and other better characterized P-type ATPases are discussed. The platform opens the venue to study translocation events and mechanisms of transport in other transition metal P-type ATPase pumps.
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Affiliation(s)
- Nisansala Abeyrathna
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX 75080, USA.
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11
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Herbert FC, Abeyrathna SS, Abeyrathna NS, Wijesundara YH, Brohlin OR, Carraro F, Amenitsch H, Falcaro P, Luzuriaga MA, Durand-Silva A, Diwakara SD, Smaldone RA, Meloni G, Gassensmith JJ. Stabilization of supramolecular membrane protein-lipid bilayer assemblies through immobilization in a crystalline exoskeleton. Nat Commun 2021; 12:2202. [PMID: 33850135 PMCID: PMC8044103 DOI: 10.1038/s41467-021-22285-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 02/25/2021] [Indexed: 11/09/2022] Open
Abstract
Artificial native-like lipid bilayer systems constructed from phospholipids assembling into unilamellar liposomes allow the reconstitution of detergent-solubilized transmembrane proteins into supramolecular lipid-protein assemblies called proteoliposomes, which mimic cellular membranes. Stabilization of these complexes remains challenging because of their chemical composition, the hydrophobicity and structural instability of membrane proteins, and the lability of interactions between protein, detergent, and lipids within micelles and lipid bilayers. In this work we demonstrate that metastable lipid, protein-detergent, and protein-lipid supramolecular complexes can be successfully generated and immobilized within zeolitic-imidazole framework (ZIF) to enhance their stability against chemical and physical stressors. Upon immobilization in ZIF bio-composites, blank liposomes, and model transmembrane metal transporters in detergent micelles or embedded in proteoliposomes resist elevated temperatures, exposure to chemical denaturants, aging, and mechanical stresses. Extensive morphological and functional characterization of the assemblies upon exfoliation reveal that all these complexes encapsulated within the framework maintain their native morphology, structure, and activity, which is otherwise lost rapidly without immobilization.
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Affiliation(s)
- Fabian C Herbert
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Sameera S Abeyrathna
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Nisansala S Abeyrathna
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Yalini H Wijesundara
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Olivia R Brohlin
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Francesco Carraro
- Institute of Physical and Theoretical Chemistry, Graz University of Technology, Graz, Austria
| | - Heinz Amenitsch
- Institute of Inorganic Chemistry, Graz University of Technology, Graz, Austria
| | - Paolo Falcaro
- Institute of Physical and Theoretical Chemistry, Graz University of Technology, Graz, Austria
| | - Michael A Luzuriaga
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Alejandra Durand-Silva
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Shashini D Diwakara
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Ronald A Smaldone
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA
| | - Gabriele Meloni
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA.
| | - Jeremiah J Gassensmith
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, USA.
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA.
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12
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Gonciarz RL, Renslo AR. Emerging role of ferrous iron in bacterial growth and host-pathogen interaction: New tools for chemical (micro)biology and antibacterial therapy. Curr Opin Chem Biol 2021; 61:170-178. [PMID: 33714882 PMCID: PMC8106656 DOI: 10.1016/j.cbpa.2021.01.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 01/25/2021] [Accepted: 01/31/2021] [Indexed: 01/27/2023]
Abstract
Chemical tools capable of detecting ferrous iron with oxidation-state specificity have only recently become available. Coincident with this development in chemical biology has been increased study and appreciation for the importance of ferrous iron during infection and more generally in host-pathogen interaction. Some of the recent findings are surprising and challenge long-standing assumptions about bacterial iron homeostasis and the innate immune response to infection. Here, we review these recent developments and their implications for antibacterial therapy.
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Affiliation(s)
- Ryan L Gonciarz
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, USA
| | - Adam R Renslo
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, USA.
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13
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Zhang Y, Sen S, Giedroc DP. Iron Acquisition by Bacterial Pathogens: Beyond Tris-Catecholate Complexes. Chembiochem 2020; 21:1955-1967. [PMID: 32180318 PMCID: PMC7367709 DOI: 10.1002/cbic.201900778] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 03/06/2020] [Indexed: 12/11/2022]
Abstract
Sequestration of the essential nutrient iron from bacterial invaders that colonize the vertebrate host is a central feature of nutritional immunity and the "fight over transition metals" at the host-pathogen interface. The iron quota for many bacterial pathogens is large, as iron enzymes often make up a significant share of the metalloproteome. Iron enzymes play critical roles in respiration, energy metabolism, and other cellular processes by catalyzing a wide range of oxidation-reduction, electron transfer, and oxygen activation reactions. In this Concept article, we discuss recent insights into the diverse ways that bacterial pathogens acquire this essential nutrient, beyond the well-characterized tris-catecholate FeIII complexes, in competition and cooperation with significant host efforts to cripple these processes. We also discuss pathogen strategies to adapt their metabolism to less-than-optimal iron concentrations, and briefly speculate on what might be an integrated adaptive response to the concurrent limitation of both iron and zinc in the infected host.
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Affiliation(s)
- Yifan Zhang
- Department of Chemistry, Indiana University, Bloomington, IN 47405-7102, USA
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405-7102, USA
| | - Sambuddha Sen
- Department of Chemistry, Indiana University, Bloomington, IN 47405-7102, USA
| | - David P Giedroc
- Department of Chemistry, Indiana University, Bloomington, IN 47405-7102, USA
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405-7102, USA
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