1
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Yang T, Zou Y, Ng HL, Kumar A, Newton SM, Klebba PE. Specificity and mechanism of TonB-dependent ferric catecholate uptake by Fiu. Front Microbiol 2024; 15:1355253. [PMID: 38601941 PMCID: PMC11005823 DOI: 10.3389/fmicb.2024.1355253] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 01/23/2024] [Indexed: 04/12/2024] Open
Abstract
We studied the Escherichia coli outer membrane protein Fiu, a presumed transporter of monomeric ferric catecholates, by introducing Cys residues in its surface loops and modifying them with fluorescein maleimide (FM). Fiu-FM bound iron complexes of the tricatecholate siderophore enterobactin (FeEnt) and glucosylated enterobactin (FeGEnt), their dicatecholate degradation product Fe(DHBS)2 (FeEnt*), the monocatecholates dihydroxybenzoic acid (FeDHBA) and dihydroxybenzoyl serine (FeDHBS), and the siderophore antibiotics cefiderocol (FDC) and MB-1. Unlike high-affinity ligand-gated porins (LGPs), Fiu-FM had only micromolar affinity for iron complexes. Its apparent KD values for FeDHBS, FeDHBA, FeEnt*, FeEnt, FeGEnt, FeFDC, and FeMB-1 were 0.1, 0.7, 0.7, 1.0, 0.3, 0.4, and 4 μM, respectively. Despite its broad binding abilities, the transport repertoires of E. coli Fiu, as well as those of Cir and FepA, were less broad. Fiu only transported FeEnt*. Cir transported FeEnt* and FeDHBS (weakly); FepA transported FeEnt, FeEnt*, and FeDHBA. Both Cir and FepA bound FeGEnt, albeit with lower affinity. Related transporters of Acinetobacter baumannii (PiuA, PirA, BauA) had similarly moderate affinity and broad specificity for di- or monomeric ferric catecholates. Both microbiological and radioisotopic experiments showed Fiu's exclusive transport of FeEnt*, rather than ferric monocatecholate compounds. Molecular docking and molecular dynamics simulations predicted three binding sites for FeEnt*in the external vestibule of Fiu, and a fourth site deeper in its interior. Alanine scanning mutagenesis in the outermost sites (1a, 1b, and 2) decreased FeEnt* binding affinity as much as 20-fold and reduced or eliminated FeEnt* uptake. Finally, the molecular dynamics simulations suggested a pathway of FeEnt* movement through Fiu that may generally describe the process of metal transport by TonB-dependent receptors.
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Affiliation(s)
| | | | | | | | | | - Phillip E. Klebba
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS, United States
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2
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Baquero F, Beis K, Craik DJ, Li Y, Link AJ, Rebuffat S, Salomón R, Severinov K, Zirah S, Hegemann JD. The pearl jubilee of microcin J25: thirty years of research on an exceptional lasso peptide. Nat Prod Rep 2024; 41:469-511. [PMID: 38164764 DOI: 10.1039/d3np00046j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Covering: 1992 up to 2023Since their discovery, lasso peptides went from peculiarities to be recognized as a major family of ribosomally synthesized and post-translationally modified peptide (RiPP) natural products that were shown to be spread throughout the bacterial kingdom. Microcin J25 was first described in 1992, making it one of the earliest known lasso peptides. No other lasso peptide has since then been studied to such an extent as microcin J25, yet, previous review articles merely skimmed over all the research done on this exceptional lasso peptide. Therefore, to commemorate the 30th anniversary of its first report, we give a comprehensive overview of all literature related to microcin J25. This review article spans the early work towards the discovery of microcin J25, its biosynthetic gene cluster, and the elucidation of its three-dimensional, threaded lasso structure. Furthermore, the current knowledge about the biosynthesis of microcin J25 and lasso peptides in general is summarized and a detailed overview is given on the biological activities associated with microcin J25, including means of self-immunity, uptake into target bacteria, inhibition of the Gram-negative RNA polymerase, and the effects of microcin J25 on mitochondria. The in vitro and in vivo models used to study the potential utility of microcin J25 in a (veterinary) medicine context are discussed and the efforts that went into employing the microcin J25 scaffold in bioengineering contexts are summed up.
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Affiliation(s)
- Fernando Baquero
- Department of Microbiology, Ramón y Cajal University Hospital and Ramón y Cajal Institute for Health Research (IRYCIS), Madrid, Spain
- Network Center for Research in Epidemiology and Public Health (CIBER-ESP), Madrid, Spain
| | - Konstantinos Beis
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
- Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot, Oxfordshire OX11 0FA, UK
| | - David J Craik
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, 4072 Brisbane, Queensland, Australia
| | - Yanyan Li
- Laboratoire Molécules de Communication et Adaptation des Microorganismes (MCAM), UMR 7245, Muséum National d'Histoire Naturelle (MNHN), Centre National de la Recherche Scientifique (CNRS), Paris, France
| | - A James Link
- Departments of Chemical and Biological Engineering, Chemistry, and Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Sylvie Rebuffat
- Laboratoire Molécules de Communication et Adaptation des Microorganismes (MCAM), UMR 7245, Muséum National d'Histoire Naturelle (MNHN), Centre National de la Recherche Scientifique (CNRS), Paris, France
| | - Raúl Salomón
- Instituto de Química Biológica "Dr Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET-UNT, San Miguel de Tucumán, Argentina
| | - Konstantin Severinov
- Waksman Institute for Microbiology, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Séverine Zirah
- Laboratoire Molécules de Communication et Adaptation des Microorganismes (MCAM), UMR 7245, Muséum National d'Histoire Naturelle (MNHN), Centre National de la Recherche Scientifique (CNRS), Paris, France
| | - Julian D Hegemann
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarland University Campus, 66123 Saarbrücken, Germany.
- Department of Pharmacy, Campus E8 1, Saarland University, 66123 Saarbrücken, Germany
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3
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Kemp P, Weber W, Desczyk C, Kaufmann M, Panthel J, Wörmann T, Stein V. Dissecting the Permeability of the Escherichia coli Cell Envelope to a Small Molecule Using Tailored Intensiometric Fluorescent Protein Sensors. ACS OMEGA 2023; 8:39562-39569. [PMID: 37901533 PMCID: PMC10601414 DOI: 10.1021/acsomega.3c05405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 09/19/2023] [Indexed: 10/31/2023]
Abstract
Membranes provide a highly selective barrier that defines the boundaries of any cell while providing an interface for communication and nutrient uptake. However, despite their central physiological role, our capacity to study or even engineer the permeation of distinct solutes across biological membranes remains rudimentary. This especially applies to Gram-negative bacteria, where the outer and inner membrane impose two permeation barriers. Addressing this analytical challenge, we exemplify how the permeability of the Escherichia coli cell envelope can be dissected using a small-molecule-responsive fluorescent protein sensor. The approach is exemplified for the biotechnologically relevant macrolide rapamycin, for which we first construct an intensiometric rapamycin detector (iRapTor) while comprehensively probing key design principles in the iRapTor scaffold. Specifically, this includes the scope of minimal copolymeric linkers as a function of topology and the concomitant need for gate post residues. In a subsequent step, we apply iRapTors to assess the permeability of the E. coli cell envelope to rapamycin. Despite its lipophilic character, rapamycin does not readily diffuse across the E. coli envelope but can be enhanced by recombinantly expressing a nanopore in the outer membrane. Our study thus provides a blueprint for studying and actuating the permeation of small molecules across the prokaryotic cell envelope.
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Affiliation(s)
- Philipp Kemp
- Department
of Biology, TU Darmstadt, 64287 Darmstadt, Germany
- Centre
for Synthetic Biology, TU Darmstadt, 64283 Darmstadt, Germany
| | - Wadim Weber
- Department
of Biology, TU Darmstadt, 64287 Darmstadt, Germany
- Centre
for Synthetic Biology, TU Darmstadt, 64283 Darmstadt, Germany
| | | | - Marwan Kaufmann
- Department
of Biology, TU Darmstadt, 64287 Darmstadt, Germany
| | | | - Theresa Wörmann
- Department
of Biology, TU Darmstadt, 64287 Darmstadt, Germany
| | - Viktor Stein
- Department
of Biology, TU Darmstadt, 64287 Darmstadt, Germany
- Centre
for Synthetic Biology, TU Darmstadt, 64283 Darmstadt, Germany
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4
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Abstract
TonB-dependent transporters (TBDTs) are present in all gram-negative bacteria and mediate energy-dependent uptake of molecules that are too scarce or large to be taken up efficiently by outer membrane (OM) diffusion channels. This process requires energy that is derived from the proton motive force and delivered to TBDTs by the TonB-ExbBD motor complex in the inner membrane. Together with the need to preserve the OM permeability barrier, this has led to an extremely complex and fascinating transport mechanism for which the fundamentals, despite decades of research, are still unclear. In this review, we describe our current understanding of the transport mechanism of TBDTs, their potential role in the delivery of novel antibiotics, and the important contributions made by TBDT-associated (lipo)proteins.
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Affiliation(s)
- Augustinas Silale
- Biosciences Institute, The Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom; ,
| | - Bert van den Berg
- Biosciences Institute, The Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom; ,
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5
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Samineni L, Acharya B, Behera H, Oh H, Kumar M, Chowdhury R. Protein engineering of pores for separation, sensing, and sequencing. Cell Syst 2023; 14:676-691. [PMID: 37591205 DOI: 10.1016/j.cels.2023.07.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 06/13/2023] [Accepted: 07/19/2023] [Indexed: 08/19/2023]
Abstract
Proteins are critical to cellular function and survival. They are complex molecules with precise structures and chemistries, which allow them to serve diverse functions for maintaining overall cell homeostasis. Since the discovery of the first enzyme in 1833, a gamut of advanced experimental and computational tools has been developed and deployed for understanding protein structure and function. Recent studies have demonstrated the ability to redesign/alter natural proteins for applications in industrial processes of interest and to make customized, novel synthetic proteins in the laboratory through protein engineering. We comprehensively review the successes in engineering pore-forming proteins and correlate the amino acid-level biochemistry of different pore modification strategies to the intended applications limited to nucleotide/peptide sequencing, single-molecule sensing, and precise molecular separations.
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Affiliation(s)
- Laxmicharan Samineni
- Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, Austin, TX 78712, USA
| | - Bibek Acharya
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011, USA
| | - Harekrushna Behera
- Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, Austin, TX 78712, USA
| | - Hyeonji Oh
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX 78712, USA
| | - Manish Kumar
- Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, Austin, TX 78712, USA; McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX 78712, USA
| | - Ratul Chowdhury
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011, USA.
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6
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Mayse LA, Movileanu L. Gating of β-Barrel Protein Pores, Porins, and Channels: An Old Problem with New Facets. Int J Mol Sci 2023; 24:12095. [PMID: 37569469 PMCID: PMC10418385 DOI: 10.3390/ijms241512095] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 07/23/2023] [Accepted: 07/25/2023] [Indexed: 08/13/2023] Open
Abstract
β barrels are ubiquitous proteins in the outer membranes of mitochondria, chloroplasts, and Gram-negative bacteria. These transmembrane proteins (TMPs) execute a wide variety of tasks. For example, they can serve as transporters, receptors, membrane-bound enzymes, as well as adhesion, structural, and signaling elements. In addition, multimeric β barrels are common structural scaffolds among many pore-forming toxins. Significant progress has been made in understanding the functional, structural, biochemical, and biophysical features of these robust and versatile proteins. One frequently encountered fundamental trait of all β barrels is their voltage-dependent gating. This process consists of reversible or permanent conformational transitions between a large-conductance, highly permeable open state and a low-conductance, solute-restrictive closed state. Several intrinsic molecular mechanisms and environmental factors modulate this universal property of β barrels. This review article outlines the typical signatures of voltage-dependent gating. Moreover, we discuss recent developments leading to a better qualitative understanding of the closure dynamics of these TMPs.
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Affiliation(s)
- Lauren A. Mayse
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, NY 13244, USA;
- Department of Biomedical and Chemical Engineering, Syracuse University, 223 Link Hall, Syracuse, NY 13244, USA
| | - Liviu Movileanu
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, NY 13244, USA;
- Department of Biomedical and Chemical Engineering, Syracuse University, 223 Link Hall, Syracuse, NY 13244, USA
- The BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
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7
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Sauer DF, Markel U, Schiffels J, Okuda J, Schwaneberg U. FhuA: From Iron-Transporting Transmembrane Protein to Versatile Scaffolds through Protein Engineering. Acc Chem Res 2023. [PMID: 37191525 DOI: 10.1021/acs.accounts.3c00060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
ConspectusProtein engineering has emerged as a powerful methodology to tailor the properties of proteins. It empowers the design of biohybrid catalysts and materials, thereby enabling the convergence of materials science, chemistry, and medicine. The choice of a protein scaffold is an important factor for performance and potential applications. In the past two decades, we utilized the ferric hydroxamate uptake protein FhuA. FhuA is, from our point of view, a versatile scaffold due to its comparably large cavity and robustness toward temperature as well as organic cosolvents. FhuA is a natural iron transporter located in the outer membrane of Escherichia coli (E. coli). Wild-type FhuA consists of 714 amino acids and has a β-barrel structure composed of 22 antiparallel β-sheets, closed by an internal globular "cork" domain (amino acids 1-160). FhuA is robust in a broad pH range and toward organic cosolvents; therefore, we envisioned FhuA to be a suitable platform for various applications in (i) biocatalysis, (ii) materials science, and (iii) the construction of artificial metalloenzymes.(i) Applications in biocatalysis were achieved by removing the globular cork domain (FhuA_Δ1-160), thereby creating a large pore for the passive transport of otherwise difficult-to-import molecules through diffusion. Introducing this FhuA variant into the outer membrane of E. coli facilitates the uptake of substrates for downstream biocatalytic conversion. Furthermore, removing the globular "cork" domain without structural collapse of the ß-barrel protein allowed the use of FhuA as a membrane filter, exhibiting a preference for d-arginine over l-arginine.(ii) FhuA is a transmembrane protein, which makes it attractive to be used for applications in non-natural polymeric membranes. Inserting FhuA into polymer vesicles yielded so-called synthosomes (i.e., catalytic synthetic vesicles in which the transmembrane protein acted as a switchable gate or filter). Our work in this direction enables polymersomes to be used in biocatalysis, DNA recovery, and the controlled (triggered) release of molecules. Furthermore, FhuA can be used as a building block to create protein-polymer conjugates to generate membranes.(iii) Artificial metalloenzymes (ArMs) are formed by incorporating a non-native metal ion or metal complex into a protein. This combines the best of two worlds: the vast reaction and substrate scope of chemocatalysis and the selectivity and evolvability of enzymes. With its large inner diameter, FhuA can harbor (bulky) metal catalysts. Among others, we covalently attached a Grubbs-Hoveyda-type catalyst for olefin metathesis to FhuA. This artificial metathease was then used in various chemical transformations, ranging from polymerizations (ring-opening metathesis polymerization) to enzymatic cascades involving cross-metathesis. Ultimately, we generated a catalytically active membrane by copolymerizing FhuA and pyrrole. The resulting biohybrid material was then equipped with the Grubbs-Hoveyda-type catalyst and used in ring-closing metathesis.The number of reports on FhuA and its various applications indicates that it is a versatile building block to generate hybrid catalysts and materials. We hope that our research will inspire future research efforts at the interface of biotechnology, catalysis, and material science in order to create biohybrid systems that offer smart solutions for current challenges in catalysis, material science, and medicine.
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Affiliation(s)
- Daniel F Sauer
- Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany
| | - Ulrich Markel
- Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany
| | - Johannes Schiffels
- Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany
| | - Jun Okuda
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Ulrich Schwaneberg
- Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany
- DWI - Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, D-52056, Aachen, Germany
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8
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Degroux S, Effantin G, Linares R, Schoehn G, Breyton C. Deciphering Bacteriophage T5 Host Recognition Mechanism and Infection Trigger. J Virol 2023; 97:e0158422. [PMID: 36779755 PMCID: PMC10062170 DOI: 10.1128/jvi.01584-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 01/05/2023] [Indexed: 02/14/2023] Open
Abstract
Bacteriophages, viruses infecting bacteria, recognize their host with high specificity, binding to either saccharide motifs or proteins of the cell wall of their host. In the majority of bacteriophages, this host recognition is performed by receptor binding proteins (RBPs) located at the extremity of a tail. Interaction between the RBPs and the host is the trigger for bacteriophage infection, but the molecular details of the mechanisms are unknown for most bacteriophages. Here, we present the electron cryomicroscopy (cryo-EM) structure of bacteriophage T5 RBPpb5 in complex with its Escherichia coli receptor, the iron ferrichrome transporter FhuA. Monomeric RBPpb5 is located at the extremity of T5's long flexible tail, and its irreversible binding to FhuA commits T5 to infection. Analysis of the structure of RBPpb5 within the complex, comparison with its AlphaFold2-predicted structure, and its fit into a previously determined map of the T5 tail tip in complex with FhuA allow us to propose a mechanism of transmission of the RBPpb5 receptor binding to the straight fiber, initiating the cascade of events that commits T5 to DNA ejection. IMPORTANCE Tailed bacteriophages specifically recognize their bacterial host by interaction of their receptor binding protein(s) (RBPs) with saccharides and/or proteins located at the surface of their prey. This crucial interaction commits the virus to infection, but the molecular details of this mechanism are unknown for the majority of bacteriophages. We determined the structure of bacteriophage T5 RBPpb5 in complex with its E. coli receptor, FhuA, by cryo-EM. This first structure of an RBP bound to its protein receptor allowed us to propose a mechanism of transmission of host recognition to the rest of the phage, ultimately opening the capsid and perforating the cell wall and, thus, allowing safe channeling of the DNA into the host cytoplasm.
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Affiliation(s)
| | | | - Romain Linares
- Université Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
| | - Guy Schoehn
- Université Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
| | - Cécile Breyton
- Université Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
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9
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Hanreich S, Bonandi E, Drienovská I. Design of Artificial Enzymes: Insights into Protein Scaffolds. Chembiochem 2023; 24:e202200566. [PMID: 36418221 DOI: 10.1002/cbic.202200566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 11/25/2022]
Abstract
The design of artificial enzymes has emerged as a promising tool for the generation of potent biocatalysts able to promote new-to-nature reactions with improved catalytic performances, providing a powerful platform for wide-ranging applications and a better understanding of protein functions and structures. The selection of an appropriate protein scaffold plays a key role in the design process. This review aims to give a general overview of the most common protein scaffolds that can be exploited for the generation of artificial enzymes. Several examples are discussed and categorized according to the strategy used for the design of the artificial biocatalyst, namely the functionalization of natural enzymes, the creation of a new catalytic site in a protein scaffold bearing a wide hydrophobic pocket and de novo protein design. The review is concluded by a comparison of these different methods and by our perspective on the topic.
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Affiliation(s)
- Stefanie Hanreich
- Department of Chemistry and Pharmaceutical Sciences Vrije Universiteit, Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam (The, Netherlands
| | - Elisa Bonandi
- Department of Chemistry and Pharmaceutical Sciences Vrije Universiteit, Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam (The, Netherlands
| | - Ivana Drienovská
- Department of Chemistry and Pharmaceutical Sciences Vrije Universiteit, Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam (The, Netherlands
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10
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Pseudomonas aeruginosa FpvB Is a High-Affinity Transporter for Xenosiderophores Ferrichrome and Ferrioxamine B. mBio 2023; 14:e0314922. [PMID: 36507834 PMCID: PMC9973354 DOI: 10.1128/mbio.03149-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Iron is essential for many biological functions in bacteria, but its poor solubility is a limiting factor for growth. Bacteria produce siderophores, soluble natural products that bind iron with high affinity, to overcome this challenge. Siderophore-iron complexes return to the cell through specific outer membrane transporters. The opportunistic pathogen Pseudomonas aeruginosa makes multiple transporters that recognize its own siderophores, pyoverdine and pyochelin, and xenosiderophores produced by other bacteria or fungi, which gives it a competitive advantage. Some antibiotics exploit these transporters to bypass the membrane to reach their intracellular targets-including the thiopeptide antibiotic, thiostrepton (TS), which uses the pyoverdine transporters FpvA and FpvB to cross the outer membrane. Here, we assessed TS susceptibility in the presence of various siderophores and discovered that ferrichrome and ferrioxamine B antagonized TS uptake via FpvB. Unexpectedly, we found that FpvB transports ferrichrome and ferrioxamine B with higher affinity than pyoverdine. Site-directed mutagenesis of FpvB coupled with competitive growth inhibition and affinity label quenching studies suggested that the siderophores and antibiotic share a binding site in an aromatic pocket formed by the plug and barrel domains but have differences in their binding mechanism and molecular determinants for uptake. This work describes an alternative uptake pathway for ferrichrome and ferrioxamine B in P. aeruginosa and emphasizes the promiscuity of siderophore transporters, with implications for Gram-negative antibiotic development via the Trojan horse approach. IMPORTANCE Gram-negative bacteria express a variety of outer membrane transporters to import critical nutrients such as iron. Due to its insolubility, iron is taken up while bound to small-molecule chelators called siderophores. Pseudomonas aeruginosa takes up its own siderophores pyoverdine and pyochelin but can also steal siderophores produced by other bacteria and fungi, giving it a competitive advantage in iron-limited environments. Here, we used whole-cell reporter assays to show that FpvB, originally identified as a secondary transporter for pyoverdine, transports the chemically distinct fungal siderophore ferrichrome and the bacterial siderophore ferrioxamine B with high affinity. FpvB is also used by thiopeptide antibiotic thiostrepton for uptake. We predicted that all of these ligands bind to a common hydrophobic pocket in FpvB and used site-directed mutagenesis coupled with phenotypic assays to identify residues required for uptake. These analyses showed that siderophore and antibiotic uptake could be uncoupled. Our data show that FpvB is a promiscuous transporter of multiple chemically distinct ligands and fills in missing details of ferrichrome transport by P. aeruginosa. A clearer picture of the spectrum of outer membrane transporter substrate specificity is useful for the design of novel siderophore-antibiotic conjugates that can exploit nutrient uptake pathways to kill challenging Gram-negative pathogens.
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11
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Surveying membrane landscapes: a new look at the bacterial cell surface. Nat Rev Microbiol 2023:10.1038/s41579-023-00862-w. [PMID: 36828896 DOI: 10.1038/s41579-023-00862-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/30/2023] [Indexed: 02/26/2023]
Abstract
Recent studies applying advanced imaging techniques are changing the way we understand bacterial cell surfaces, bringing new knowledge on everything from single-cell heterogeneity in bacterial populations to their drug sensitivity and mechanisms of antimicrobial resistance. In both Gram-positive and Gram-negative bacteria, the outermost surface of the bacterial cell is being imaged at nanoscale; as a result, topographical maps of bacterial cell surfaces can be constructed, revealing distinct zones and specific features that might uniquely identify each cell in a population. Functionally defined assembly precincts for protein insertion into the membrane have been mapped at nanoscale, and equivalent lipid-assembly precincts are suggested from discrete lipopolysaccharide patches. As we review here, particularly for Gram-negative bacteria, the applications of various modalities of nanoscale imaging are reawakening our curiosity about what is conceptually a 3D cell surface landscape: what it looks like, how it is made and how it provides resilience to respond to environmental impacts.
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12
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Mathieu‐Gaedke M, Böker A, Glebe U. How to Characterize the Protein Structure and Polymer Conformation in Protein‐Polymer Conjugates – a Perspective. MACROMOL CHEM PHYS 2023. [DOI: 10.1002/macp.202200353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Maria Mathieu‐Gaedke
- Chair of Polymer Materials and Polymer Technologies Institute of Chemistry University of Potsdam Karl‐Liebknecht‐Str. 24–25 14476 Potsdam‐Golm Germany
- Fraunhofer Institute for Applied Polymer Research IAP Geiselbergstr. 69 14476 Potsdam‐Golm Germany
| | - Alexander Böker
- Chair of Polymer Materials and Polymer Technologies Institute of Chemistry University of Potsdam Karl‐Liebknecht‐Str. 24–25 14476 Potsdam‐Golm Germany
- Fraunhofer Institute for Applied Polymer Research IAP Geiselbergstr. 69 14476 Potsdam‐Golm Germany
| | - Ulrich Glebe
- Chair of Polymer Materials and Polymer Technologies Institute of Chemistry University of Potsdam Karl‐Liebknecht‐Str. 24–25 14476 Potsdam‐Golm Germany
- Fraunhofer Institute for Applied Polymer Research IAP Geiselbergstr. 69 14476 Potsdam‐Golm Germany
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13
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Prado LCDS, Giacchetto Felice A, Rodrigues TCV, Tiwari S, Andrade BS, Kato RB, Oliveira CJF, Silva MV, Barh D, Azevedo VADC, Jaiswal AK, Soares SDC. New putative therapeutic targets against Serratia marcescens using reverse vaccinology and subtractive genomics. J Biomol Struct Dyn 2022; 40:10106-10121. [PMID: 34192477 DOI: 10.1080/07391102.2021.1942211] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The Gram-negative bacillus Serratia marcescens, a member of Enterobacteriaceae family, is an opportunistic nosocomial pathogen commonly found in hospital outbreaks that can cause infections in the urinary tract, bloodstream, central nervous system and pneumonia. Because S. marcescens strains are resistant to several antibiotics, it is critical the need for effective treatments, including new drugs and vaccines. Here, we applied reverse vaccinology and subtractive genomic approaches for the in silico prediction of potential vaccine and drug targets against 59 strains of S. marcescens. We found 759 core non-host homologous proteins, of which 87 are putative surface-exposed proteins, 183 secreted proteins, and 80 membrane proteins. From these proteins, we predicted seven candidates vaccine targets: a sn-glycerol-3-phosphate-binding periplasmic protein UgpB, a vitamin B12 TonB-dependent receptor, a ferrichrome porin FhuA, a divisome-associated lipoprotein YraP, a membrane-bound lytic murein transglycosylase A, a peptidoglycan lytic exotransglycosylase, and a DUF481 domain-containing protein. We also predicted two drug targets: a N(4)-acetylcytidine amidohydrolase, and a DUF1428 family protein. Using the molecular docking approach for each drug target, we identified and selected ZINC04259491 and ZINC04235390 molecules as the most favorable interactions with the target active site residues. Our findings may contribute to the development of vaccines and new drug targets against S. marcescens. Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Ligia Carolina da Silva Prado
- Inter-unit Post-Graduate Program in Bioinformatics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Andrei Giacchetto Felice
- Department of Microbiology, Immunology and Parasitology, Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro, Uberaba, MG, Brazil
| | - Thaís Cristina Vilela Rodrigues
- Inter-unit Post-Graduate Program in Bioinformatics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Sandeep Tiwari
- Inter-unit Post-Graduate Program in Bioinformatics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Bruno Silva Andrade
- Laboratory of Bioinformatics and Computational Chemistry, State University of Southwest of Bahia, Bahia, Brazil
| | - Rodrigo Bentes Kato
- Inter-unit Post-Graduate Program in Bioinformatics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Carlo José Freire Oliveira
- Department of Microbiology, Immunology and Parasitology, Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro, Uberaba, MG, Brazil
| | - Marcos Vinicius Silva
- Department of Microbiology, Immunology and Parasitology, Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro, Uberaba, MG, Brazil
| | - Debmalya Barh
- Centre for Genomics and Applied Gene Technology, Institute of Integrative Omics and Applied Biotechnology, Nonakuri, West Bengal, India
| | - Vasco Ariston de Carvalho Azevedo
- Inter-unit Post-Graduate Program in Bioinformatics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Arun Kumar Jaiswal
- Inter-unit Post-Graduate Program in Bioinformatics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Siomar de Castro Soares
- Department of Microbiology, Immunology and Parasitology, Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro, Uberaba, MG, Brazil
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14
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Structural basis for host recognition and superinfection exclusion by bacteriophage T5. Proc Natl Acad Sci U S A 2022; 119:e2211672119. [PMID: 36215462 PMCID: PMC9586334 DOI: 10.1073/pnas.2211672119] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Bacteriophages, viruses that prey on bacteria, are the most abundant organisms on Earth and play a crucial role in shaping microbial ecosystems. A key event, still poorly understood at the molecular level, in the bacteriophage life cycle is the interaction of phage receptor-binding proteins with receptors on the bacterial cell surface, leading ultimately to phage propagation. Another important and understudied process in phage biology is superinfection exclusion (SE), which prevents secondary infections by the same or similar viruses. Here, we visualize, for the model phage T5, how host recognition and SE can be achieved via the interaction of different phage proteins with the same receptor in the Escherichia coli outer membrane. A key but poorly understood stage of the bacteriophage life cycle is the binding of phage receptor-binding proteins (RBPs) to receptors on the host cell surface, leading to injection of the phage genome and, for lytic phages, host cell lysis. To prevent secondary infection by the same or a closely related phage and nonproductive phage adsorption to lysed cell fragments, superinfection exclusion (SE) proteins can prevent the binding of RBPs via modulation of the host receptor structure in ways that are also unclear. Here, we present the cryogenic electron microscopy (cryo-EM) structure of the phage T5 outer membrane (OM) receptor FhuA in complex with the T5 RBP pb5, and the crystal structure of FhuA complexed to the OM SE lipoprotein Llp. Pb5 inserts four loops deeply into the extracellular lumen of FhuA and contacts the plug but does not cause any conformational changes in the receptor, supporting the view that DNA translocation does not occur through the lumen of OM channels. The FhuA–Llp structure reveals that Llp is periplasmic and binds to a nonnative conformation of the plug of FhuA, causing the inward folding of two extracellular loops via “reverse” allostery. The inward-folded loops of FhuA overlap with the pb5 binding site, explaining how Llp binding to FhuA abolishes further infection of Escherichia coli by phage T5 and suggesting a mechanism for SE via the jamming of TonB-dependent transporters by small phage lipoproteins.
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15
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Recent Advances in Aptamer‐Based Nanopore Sensing at Single‐Molecule Resolution. Chem Asian J 2022; 17:e202200364. [DOI: 10.1002/asia.202200364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/20/2022] [Indexed: 11/07/2022]
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16
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The Thermodynamic Stability of Membrane Proteins in Micelles and Lipid Bilayers Investigated with the Ferrichrom Receptor FhuA. J Membr Biol 2022; 255:485-502. [PMID: 35552784 PMCID: PMC9581862 DOI: 10.1007/s00232-022-00238-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 04/05/2022] [Indexed: 12/03/2022]
Abstract
Extraction of integral membrane proteins into detergents for structural and functional studies often leads to a strong loss in protein stability. The impact of the lipid bilayer on the thermodynamic stability of an integral membrane protein in comparison to its solubilized form in detergent was examined and compared for FhuA from Escherichia coli and for a mutant, FhuAΔ5-160, lacking the N-terminal cork domain. Urea-induced unfolding was monitored by fluorescence spectroscopy to determine the effective free energies \documentclass[12pt]{minimal}
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\begin{document}$$ \Delta G{^\text{o}_{\rm u}} $$\end{document}ΔGuo of unfolding. To obtain enthalpic and entropic contributions of unfolding of FhuA, \documentclass[12pt]{minimal}
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\begin{document}$$ \Delta G{^\text{o}_{\rm u}} $$\end{document}ΔGuo were determined at various temperatures. When solubilized in LDAO detergent, wt-FhuA and FhuAΔ5-160 unfolded in a single step. The 155-residue cork domain stabilized wt-FhuA by \documentclass[12pt]{minimal}
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\begin{document}$$ \Delta\Delta G{^\text{o}_{\rm u}} $$\end{document}ΔΔGuo~ 40 kJ/mol. Reconstituted into lipid bilayers, wt-FhuA unfolded in two steps, while FhuAΔ5-160 unfolded in a single step, indicating an uncoupled unfolding of the cork domain. For FhuAΔ5-160 at 35 °C, \documentclass[12pt]{minimal}
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\begin{document}$$ \Delta G{^\text{o}_{\rm u}} $$\end{document}ΔGuo increased from ~ 5 kJ/mol in LDAO micelles to about ~ 20 kJ/mol in lipid bilayers, while the temperature of unfolding increased from TM ~ 49 °C in LDAO micelles to TM ~ 75 °C in lipid bilayers. Enthalpies \documentclass[12pt]{minimal}
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\begin{document}$$\Delta H{_{\rm M}^\text{o}}$$\end{document}ΔHMowere much larger than free energies \documentclass[12pt]{minimal}
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\begin{document}$$ \Delta G{^\text{o}_{\rm u}} $$\end{document}ΔGuo, for FhuAΔ5-160 and for wt-FhuA, and compensated by a large gain of entropy upon unfolding. The gain in conformational entropy is expected to be similar for unfolding of FhuA from micelles or bilayers. The strongly increased TM and \documentclass[12pt]{minimal}
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\begin{document}$$\Delta H{_{\rm M}^\text{o}}$$\end{document}ΔHMo observed for the lipid bilayer-reconstituted FhuA in comparison to the LDAO-solubilized forms, therefore, very likely arise from a much-increased solvation entropy of FhuA in bilayers.
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17
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Kumar A, Yang T, Chakravorty S, Majumdar A, Nairn BL, Six DA, Marcondes Dos Santos N, Price SL, Lawrenz MB, Actis LA, Marques M, Russo TA, Newton SM, Klebba PE. Fluorescent sensors of siderophores produced by bacterial pathogens. J Biol Chem 2022; 298:101651. [PMID: 35101443 PMCID: PMC8921320 DOI: 10.1016/j.jbc.2022.101651] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/24/2022] [Accepted: 01/25/2022] [Indexed: 11/25/2022] Open
Abstract
Siderophores are iron-chelating molecules that solubilize Fe3+ for microbial utilization and facilitate colonization or infection of eukaryotes by liberating host iron for bacterial uptake. By fluorescently labeling membrane receptors and binding proteins, we created 20 sensors that detect, discriminate, and quantify apo- and ferric siderophores. The sensor proteins originated from TonB-dependent ligand-gated porins (LGPs) of Escherichia coli (Fiu, FepA, Cir, FhuA, IutA, BtuB), Klebsiella pneumoniae (IroN, FepA, FyuA), Acinetobacter baumannii (PiuA, FepA, PirA, BauA), Pseudomonas aeruginosa (FepA, FpvA), and Caulobacter crescentus (HutA) from a periplasmic E. coli binding protein (FepB) and from a human serum binding protein (siderocalin). They detected ferric catecholates (enterobactin, degraded enterobactin, glucosylated enterobactin, dihydroxybenzoate, dihydroxybenzoyl serine, cefidericol, MB-1), ferric hydroxamates (ferrichromes, aerobactin), mixed iron complexes (yersiniabactin, acinetobactin, pyoverdine), and porphyrins (hemin, vitamin B12). The sensors defined the specificities and corresponding affinities of the LGPs and binding proteins and monitored ferric siderophore and porphyrin transport by microbial pathogens. We also quantified, for the first time, broad recognition of diverse ferric complexes by some LGPs, as well as monospecificity for a single metal chelate by others. In addition to their primary ferric siderophore ligands, most LGPs bound the corresponding aposiderophore with ∼100-fold lower affinity. These sensors provide insights into ferric siderophore biosynthesis and uptake pathways in free-living, commensal, and pathogenic Gram-negative bacteria.
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Affiliation(s)
- Ashish Kumar
- Department of Biochemistry & Molecular Biophysics, Kansas State University, Manhattan, Kansas, USA
| | - Taihao Yang
- Department of Biochemistry & Molecular Biophysics, Kansas State University, Manhattan, Kansas, USA
| | - Somnath Chakravorty
- Department of Biochemistry & Molecular Biophysics, Kansas State University, Manhattan, Kansas, USA; Department of Medicine, Jacobs School of Medicine & Biomedical Sciences, University of Buffalo School of Medicine, Buffalo, New York, USA
| | - Aritri Majumdar
- Department of Biochemistry & Molecular Biophysics, Kansas State University, Manhattan, Kansas, USA
| | - Brittany L Nairn
- Department of Biological Sciences, Bethel University, St. Paul, Minnesota, USA
| | - David A Six
- Department of Biology, Venatorx Pharmaceuticals, Inc, Malvern, Pennsylvania, USA
| | - Naara Marcondes Dos Santos
- Departamento de Microbiologia, Instituto de Ciencias Biomedicas, Universidade de São Paulo, São Paulo, Brazil
| | - Sarah L Price
- Department of Microbiology and Immunology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Matthew B Lawrenz
- Department of Microbiology and Immunology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Luis A Actis
- Department of Microbiology, Miami University, Oxford, Ohio, USA
| | - Marilis Marques
- Departamento de Microbiologia, Instituto de Ciencias Biomedicas, Universidade de São Paulo, São Paulo, Brazil
| | - Thomas A Russo
- Department of Medicine, Jacobs School of Medicine & Biomedical Sciences, University of Buffalo School of Medicine, Buffalo, New York, USA
| | - Salete M Newton
- Department of Biochemistry & Molecular Biophysics, Kansas State University, Manhattan, Kansas, USA
| | - Phillip E Klebba
- Department of Biochemistry & Molecular Biophysics, Kansas State University, Manhattan, Kansas, USA.
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18
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Sun J, Thakur AK, Movileanu L. Current noise of a protein-selective biological nanopore. Proteomics 2022; 22:e2100077. [PMID: 34275190 PMCID: PMC8763983 DOI: 10.1002/pmic.202100077] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 06/27/2021] [Accepted: 07/15/2021] [Indexed: 11/08/2022]
Abstract
1/f current noise is ubiquitous in protein pores, porins, and channels. We have previously shown that a protein-selective biological nanopore with an external protein receptor can function as a 1/f noise generator when a high-affinity protein ligand is reversibly captured by the receptor. Here, we demonstrate that the binding affinity and concentration of the ligand are key determinants for the nature of current noise. For example, 1/f was absent when a protein ligand was reversibly captured at a much lower concentration than its equilibrium dissociation constant against the receptor. Furthermore, we also analyzed the composite current noise that resulted from mixtures of low-affinity and high-affinity ligands against the same receptor. This study highlights the significance of protein recognition events in the current noise fluctuations across biological membranes.
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Affiliation(s)
- Jiaxin Sun
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA
| | - Avinash Kumar Thakur
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA
| | - Liviu Movileanu
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA,The BioInspired Institute, Syracuse University, Syracuse, New York 13244, USA,Department of Biomedical and Chemical Engineering, Syracuse University, 329 Link Hall, Syracuse, New York 13244, USA,The corresponding author’s contact information: Liviu Movileanu, PhD, Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA. Phone: 315-443-8078;
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19
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Mayse LA, Imran A, Larimi MG, Cosgrove MS, Wolfe AJ, Movileanu L. Disentangling the recognition complexity of a protein hub using a nanopore. Nat Commun 2022; 13:978. [PMID: 35190547 PMCID: PMC8861093 DOI: 10.1038/s41467-022-28465-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 01/25/2022] [Indexed: 11/12/2022] Open
Abstract
WD40 repeat proteins are frequently involved in processing cell signaling and scaffolding large multi-subunit machineries. Despite their significance in physiological and disease-like conditions, their reversible interactions with other proteins remain modestly examined. Here, we show the development and validation of a protein nanopore for the detection and quantification of WD40 repeat protein 5 (WDR5), a chromatin-associated hub involved in epigenetic regulation of histone methylation. Our nanopore sensor is equipped with a 14-residue Win motif of mixed lineage leukemia 4 methyltransferase (MLL4Win), a WDR5 ligand. Our approach reveals a broad dynamic range of MLL4Win-WDR5 interactions and three distant subpopulations of binding events, representing three modes of protein recognition. The three binding events are confirmed as specific interactions using a weakly binding WDR5 derivative and various environmental contexts. These outcomes demonstrate the substantial sensitivity of our nanopore sensor, which can be utilized in protein analytics. Nanopores are powerful tools for sampling protein-peptide interactions. Here, the authors convert a protein-based nanopore into a sensitive biosensor to characterize the complex binding of WDR5 protein to a 14-residue ligand.
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20
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Braun V, Hartmann MD, Hantke K. Transcription regulation of iron carrier transport genes by ECF sigma factors through signaling from the cell surface into the cytoplasm. FEMS Microbiol Rev 2022; 46:6524835. [PMID: 35138377 PMCID: PMC9249621 DOI: 10.1093/femsre/fuac010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 01/26/2022] [Accepted: 02/07/2022] [Indexed: 12/02/2022] Open
Abstract
Bacteria are usually iron-deficient because the Fe3+ in their environment is insoluble or is incorporated into proteins. To overcome their natural iron limitation, bacteria have developed sophisticated iron transport and regulation systems. In gram-negative bacteria, these include iron carriers, such as citrate, siderophores, and heme, which when loaded with Fe3+ adsorb with high specificity and affinity to outer membrane proteins. Binding of the iron carriers to the cell surface elicits a signal that initiates transcription of iron carrier transport and synthesis genes, referred to as “cell surface signaling”. Transcriptional regulation is not coupled to transport. Outer membrane proteins with signaling functions contain an additional N-terminal domain that in the periplasm makes contact with an anti-sigma factor regulatory protein that extends from the outer membrane into the cytoplasm. Binding of the iron carriers to the outer membrane receptors elicits proteolysis of the anti-sigma factor by two different proteases, Prc in the periplasm, and RseP in the cytoplasmic membrane, inactivates the anti-sigma function or results in the generation of an N-terminal peptide of ∼50 residues with pro-sigma activity yielding an active extracytoplasmic function (ECF) sigma factor. Signal recognition and signal transmission into the cytoplasm is discussed herein.
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Affiliation(s)
- Volkmar Braun
- Max Planck Institute for Biology, Department of Protein Evolution, Max Planck Ring 5, 72076 Tübingen, Germany
| | - Marcus D Hartmann
- Max Planck Institute for Biology, Department of Protein Evolution, Max Planck Ring 5, 72076 Tübingen, Germany
| | - Klaus Hantke
- IMIT Institute, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
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21
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Johnson J, Ellis MJ, Piquette ZA, MacNair C, Carfrae L, Bhando T, Ritchie NE, Saliba P, Brown ED, Magolan J. Antibacterial Activity of Metergoline Analogues: Revisiting the Ergot Alkaloid Scaffold for Antibiotic Discovery. ACS Med Chem Lett 2022; 13:284-291. [PMID: 35178184 PMCID: PMC8842143 DOI: 10.1021/acsmedchemlett.1c00648] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 01/19/2022] [Indexed: 12/22/2022] Open
Abstract
Metergoline is a semisynthetic ergot alkaloid identified recently as an inhibitor of the Gram-negative intracellular pathogen Salmonella Typhimurium (S. Tm). With the previously unknown antibacterial activity of metergoline, we explored structure-activity relationships (SARs) with a series of carbamate, urea, sulfonamide, amine, and amide analogues. Cinnamide and arylacrylamide derivatives show improved potency relative to metergoline against Gram-positive bacteria, and pyridine derivative 38 is also effective against methicillin-resistant Staphylococcus aureus (MRSA) in a murine skin infection model. Arylacrylamide analogues of metergoline show modest activity against wild-type (WT) Gram-negative bacteria but are more active against strains of efflux-deficient S. Tm and hyperpermeable Escherichia coli. The potencies against WT strains of E. coli, Acinetobacter baumannii, and Burkholderia cenocepacia are also improved considerably (up to >128-fold) with the outer-membrane permeabilizer SPR741, suggesting that the ergot scaffold represents a new lead for the development of new antibiotics.
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22
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Chen M, Shi X, Yu Z, Fan G, Serysheva II, Baker ML, Luisi BF, Ludtke SJ, Wang Z. In situ structure of the AcrAB-TolC efflux pump at subnanometer resolution. Structure 2022; 30:107-113.e3. [PMID: 34506732 PMCID: PMC8741639 DOI: 10.1016/j.str.2021.08.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 06/22/2021] [Accepted: 08/18/2021] [Indexed: 01/09/2023]
Abstract
The tripartite AcrAB-TolC assembly, which spans both the inner and outer membranes in Gram-negative bacteria, is an efflux pump that contributes to multidrug resistance. Here, we present the in situ structure of full-length Escherichia coli AcrAB-TolC determined at 7 Å resolution by electron cryo-tomography. The TolC channel penetrates the outer membrane bilayer through to the outer leaflet and exhibits two different configurations that differ by a 60° rotation relative to the AcrB position in the pump assembly. AcrA protomers interact directly with the inner membrane and with AcrB via an interface located in proximity to the AcrB ligand-binding pocket. Our structural analysis suggests that these AcrA-bridged interactions underlie an allosteric mechanism for transmitting drug-evoked signals from AcrB to the TolC channel within the pump. Our study demonstrates the power of in situ electron cryo-tomography, which permits critical insights into the function of bacterial efflux pumps.
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Affiliation(s)
- Muyuan Chen
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Xiaodong Shi
- Jiangsu Province Key Laboratory of Anesthesiology and Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Zhili Yu
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Guizhen Fan
- Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, McGovern Medical School at the University of Texas Health Science Center, Houston, TX 77030, USA
| | - Irina I Serysheva
- Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, McGovern Medical School at the University of Texas Health Science Center, Houston, TX 77030, USA
| | - Matthew L Baker
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, McGovern Medical School at the University of Texas Health Science Center, Houston, TX 77030, USA
| | - Ben F Luisi
- Department of Biochemistry, University of Cambridge, Cambridge CB21GA, UK
| | - Steven J Ludtke
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zhao Wang
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
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23
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Cao L, Do T, Link AJ. Mechanisms of action of ribosomally synthesized and posttranslationally modified peptides (RiPPs). J Ind Microbiol Biotechnol 2021; 48:6121428. [PMID: 33928382 PMCID: PMC8183687 DOI: 10.1093/jimb/kuab005] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 01/22/2021] [Indexed: 12/19/2022]
Abstract
Natural products remain a critical source of medicines and drug leads. One of the most rapidly growing superclasses of natural products is RiPPs: ribosomally synthesized and posttranslationally modified peptides. RiPPs have rich and diverse bioactivities. This review highlights examples of the molecular mechanisms of action that underly those bioactivities. Particular emphasis is placed on RiPP/target interactions for which there is structural information. This detailed mechanism of action work is critical toward the development of RiPPs as therapeutics and can also be used to prioritize hits in RiPP genome mining studies.
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Affiliation(s)
- Li Cao
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Truc Do
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - A James Link
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA.,Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.,Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
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24
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Klebba PE, Newton SMC, Six DA, Kumar A, Yang T, Nairn BL, Munger C, Chakravorty S. Iron Acquisition Systems of Gram-negative Bacterial Pathogens Define TonB-Dependent Pathways to Novel Antibiotics. Chem Rev 2021; 121:5193-5239. [PMID: 33724814 PMCID: PMC8687107 DOI: 10.1021/acs.chemrev.0c01005] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Iron is an indispensable metabolic cofactor in both pro- and eukaryotes, which engenders a natural competition for the metal between bacterial pathogens and their human or animal hosts. Bacteria secrete siderophores that extract Fe3+ from tissues, fluids, cells, and proteins; the ligand gated porins of the Gram-negative bacterial outer membrane actively acquire the resulting ferric siderophores, as well as other iron-containing molecules like heme. Conversely, eukaryotic hosts combat bacterial iron scavenging by sequestering Fe3+ in binding proteins and ferritin. The variety of iron uptake systems in Gram-negative bacterial pathogens illustrates a range of chemical and biochemical mechanisms that facilitate microbial pathogenesis. This document attempts to summarize and understand these processes, to guide discovery of immunological or chemical interventions that may thwart infectious disease.
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Affiliation(s)
- Phillip E Klebba
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Salete M C Newton
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - David A Six
- Venatorx Pharmaceuticals, Inc., 30 Spring Mill Drive, Malvern, Pennsylvania 19355, United States
| | - Ashish Kumar
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Taihao Yang
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Brittany L Nairn
- Department of Biological Sciences, Bethel University, 3900 Bethel Drive, St. Paul, Minnesota 55112, United States
| | - Colton Munger
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Somnath Chakravorty
- Jacobs School of Medicine and Biomedical Sciences, SUNY Buffalo, Buffalo, New York 14203, United States
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25
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Pollet RM, Martin LM, Koropatkin NM. TonB-dependent transporters in the Bacteroidetes: Unique domain structures and potential functions. Mol Microbiol 2021; 115:490-501. [PMID: 33448497 DOI: 10.1111/mmi.14683] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 01/10/2021] [Accepted: 01/11/2021] [Indexed: 12/26/2022]
Abstract
The human gut microbiota endows the host with a wealth of metabolic functions central to health, one of which is the degradation and fermentation of complex carbohydrates. The Bacteroidetes are one of the dominant bacterial phyla of this community and possess an expanded capacity for glycan utilization. This is mediated via the coordinated expression of discrete polysaccharide utilization loci (PUL) that invariantly encode a TonB-dependent transporter (SusC) that works with a glycan-capturing lipoprotein (SusD). More broadly within Gram-negative bacteria, TonB-dependent transporters (TBDTs) are deployed for the uptake of not only sugars, but also more often for essential nutrients such as iron and vitamins. Here, we provide a comprehensive look at the repertoire of TBDTs found in the model gut symbiont Bacteroides thetaiotaomicron and the range of predicted functional domains associated with these transporters and SusD proteins for the uptake of both glycans and other nutrients. This atlas of the B. thetaiotaomicron TBDTs reveals that there are at least three distinct subtypes of these transporters encoded within its genome that are presumably regulated in different ways to tune nutrient uptake.
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Affiliation(s)
| | - Lauryn M Martin
- Department of Biology, Alcorn State University, Alcorn, MS, USA
| | - Nicole M Koropatkin
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA
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26
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Larimi MG, Ha JH, Loh SN, Movileanu L. Insertion state of modular protein nanopores into a membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183570. [PMID: 33529578 DOI: 10.1016/j.bbamem.2021.183570] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 01/06/2021] [Accepted: 01/13/2021] [Indexed: 01/04/2023]
Abstract
In the past decade, significant progress has been made in the development of new protein nanopores. Despite these advancements, there is a pressing need for the creation of nanopores equipped with relatively large functional groups for the sampling of biomolecular events on their extramembranous side. Here, we designed, produced, and analyzed protein nanopores encompassing a robust truncation of a monomeric β-barrel membrane protein. An exogenous stably folded protein was anchored within the aqueous phase via a flexible peptide tether of varying length. We have extensively examined the pore-forming properties of these modular protein nanopores using protein engineering and single-molecule electrophysiology. This study revealed distinctions in the nanopore conductance and current fluctuations that arose from tethering the exogenous protein to either the N terminus or the C terminus. Remarkably, these nanopores insert into a planar lipid membrane with one specific conductance among a set of three substate conductance values. Moreover, we demonstrate that the occurrence probabilities of these insertion substates depend on the length of the peptide tether, the orientation of the exogenous protein with respect to the nanopore opening, and the molecular mass of tethered protein. In addition, the three conductance values remain unaltered by major changes in the composition of modular nanopores. The outcomes of this work serve as a platform for further developments in areas of protein engineering of transmembrane pores and biosensor technology.
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Affiliation(s)
| | - Jeung-Hoi Ha
- Department of Biochemistry and Molecular Biology, State University of New York - Upstate Medical University, 4249 Weiskotten Hall, 766 Irving Avenue, Syracuse, NY 13210, USA
| | - Stewart N Loh
- Department of Biochemistry and Molecular Biology, State University of New York - Upstate Medical University, 4249 Weiskotten Hall, 766 Irving Avenue, Syracuse, NY 13210, USA
| | - Liviu Movileanu
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, NY 13244-1130, USA; Department of Biomedical and Chemical Engineering, Syracuse University, 329 Link Hall, Syracuse, NY 13244, USA.
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27
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Stieger B, Steiger J, Locher KP. Membrane lipids and transporter function. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166079. [PMID: 33476785 DOI: 10.1016/j.bbadis.2021.166079] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 12/12/2020] [Accepted: 01/07/2021] [Indexed: 02/07/2023]
Abstract
Transport proteins are essential for cells in allowing the exchange of substances between cells and their environment across the lipid bilayer forming a tight barrier. Membrane lipids modulate the function of transmembrane proteins such as transporters in two ways: Lipids are tightly and specifically bound to transport proteins and in addition they modulate from the bulk of the lipid bilayer the function of transport proteins. This overview summarizes currently available information at the ultrastructural level on lipids tightly bound to transport proteins and the impact of altered bulk membrane lipid composition. Human diseases leading to altered lipid homeostasis will lead to altered membrane lipid composition, which in turn affect the function of transporter proteins.
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Affiliation(s)
- Bruno Stieger
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, University of Zurich, 8091 Zurich, Switzerland.
| | - Julia Steiger
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, University of Zurich, 8091 Zurich, Switzerland
| | - Kaspar P Locher
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
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28
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Crnković A, Srnko M, Anderluh G. Biological Nanopores: Engineering on Demand. Life (Basel) 2021; 11:life11010027. [PMID: 33466427 PMCID: PMC7824896 DOI: 10.3390/life11010027] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/24/2020] [Accepted: 12/31/2020] [Indexed: 12/17/2022] Open
Abstract
Nanopore-based sensing is a powerful technique for the detection of diverse organic and inorganic molecules, long-read sequencing of nucleic acids, and single-molecule analyses of enzymatic reactions. Selected from natural sources, protein-based nanopores enable rapid, label-free detection of analytes. Furthermore, these proteins are easy to produce, form pores with defined sizes, and can be easily manipulated with standard molecular biology techniques. The range of possible analytes can be extended by using externally added adapter molecules. Here, we provide an overview of current nanopore applications with a focus on engineering strategies and solutions.
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29
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Sun J, Thakur AK, Movileanu L. Protein Ligand-Induced Amplification in the 1/ f Noise of a Protein-Selective Nanopore. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:15247-15257. [PMID: 33307706 PMCID: PMC7755739 DOI: 10.1021/acs.langmuir.0c02498] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Previous studies of transmembrane protein channels have employed noise analysis to examine their statistical current fluctuations. In general, these explorations determined a substrate-induced amplification in the Gaussian white noise of these systems at a low-frequency regime. This outcome implies a lack of slowly appearing fluctuations in the number and local mobility of diffusing charges in the presence of channel substrates. Such parameters are among the key factors in generating a low-frequency 1/f noise. Here, we show that a protein-selective biological nanopore exhibits a substrate-induced amplification in the 1/f noise. The modular composition of this biological nanopore includes a hydrophilic transmembrane protein pore fused to a water-soluble binding protein on its extramembranous side. In addition, this protein nanopore shows an open substate populated by a high-frequency current noise because of the flickering of an engineered polypeptide adaptor at the tip of the pore. However, the physical association of the protein ligand with the binding domain reversibly switches the protein nanopore from a high-frequency noise substate into a quiet substate. In the absence of the protein ligand, our nanopore shows a low-frequency white noise. Remarkably, in the presence of the protein ligand, an amplified low-frequency 1/f noise was detected in a ligand concentration-dependent fashion. This finding suggests slowly occurring equilibrium fluctuations in the density and local mobility of charge carriers under these conditions. Furthermore, we report that the excess in 1/f noise is generated by reversible switches between the noisy ligand-released substate and the quiet ligand-captured substate. Finally, quantitative aspects of the low-frequency 1/f noise are in accord with theoretical predictions of the current noise analysis of protein channel-ligand interactions.
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Affiliation(s)
- Jiaxin Sun
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA
| | - Avinash Kumar Thakur
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA
- Structural Biology, Biochemistry, and Biophysics Program, Syracuse University, 111 College Place, Syracuse, New York 13244-4100, USA
| | - Liviu Movileanu
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA
- Structural Biology, Biochemistry, and Biophysics Program, Syracuse University, 111 College Place, Syracuse, New York 13244-4100, USA
- Department of Biomedical and Chemical Engineering, Syracuse University, 329 Link Hall, Syracuse, New York 13244, USA
- The corresponding author’s contact information: Liviu Movileanu, PhD, Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA. Phone: 315-443-8078; Fax: 315-443-9103;
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30
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Exploiting phage receptor binding proteins to enable endolysins to kill Gram-negative bacteria. Sci Rep 2020; 10:12087. [PMID: 32694655 PMCID: PMC7374709 DOI: 10.1038/s41598-020-68983-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 07/02/2020] [Indexed: 01/21/2023] Open
Abstract
Bacteriophage-encoded endolysins degrading the bacterial peptidoglycan are promising antibacterials for combating antibiotic-resistant bacteria. However, endolysins have limited use against Gram-negative bacteria, since the outer membrane prevents access to the peptidoglycan. Here, we present Innolysins, an innovative concept for engineering endolysins to exert antibacterial activity against Gram-negative bacteria. Innolysins combine the enzymatic activity of endolysins with the binding capacity of phage receptor binding proteins (RBPs). As proof-of-concept, we constructed 12 Innolysins by fusing phage T5 endolysin and RBP Pb5 in different configurations. One of these, Innolysin Ec6 displayed antibacterial activity against Escherichia coli only in the presence of Pb5 receptor FhuA, leading to 1.22 ± 0.12 log reduction in cell counts. Accordingly, other bacterial species carrying FhuA homologs such as Shigella sonnei and Pseudomonas aeruginosa were sensitive to Innolysin Ec6. To enhance the antibacterial activity, we further constructed 228 novel Innolysins by fusing 23 endolysins with Pb5. High-throughput screening allowed to select Innolysin Ec21 as the best antibacterial candidate, leading to 2.20 ± 0.09 log reduction in E. coli counts. Interestingly, Innolysin Ec21 also displayed bactericidal activity against E. coli resistant to third-generation cephalosporins, reaching a 3.31 ± 0.53 log reduction in cell counts. Overall, the Innolysin approach expands previous endolysin-engineering strategies, allowing customization of endolysins by exploiting phage RBPs to specifically target Gram-negative bacteria.
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31
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Keth J, Johann T, Frey H. Hydroxamic Acid: An Underrated Moiety? Marrying Bioinorganic Chemistry and Polymer Science. Biomacromolecules 2020; 21:2546-2556. [PMID: 32525665 DOI: 10.1021/acs.biomac.0c00449] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Even 150 years after their discovery, hydroxamic acids are mainly known as the starting material for the Lossen rearrangement in textbooks. However, hydroxamic acids feature a plethora of existing and potential applications ranging from medical purposes to materials science, based on their excellent complexation properties. This underrated functional moiety can undergo a broad variety of organic transformations and possesses unique coordination properties for a large variety of metal ions, for example, Fe(III), Zn(II), Mn(II), and Cr(III). This renders it ideal for biomedical applications in the field of metal-associated diseases or the inhibition of metalloenzymes, as well as for the separation of metals. Considering their chemical stability and reactivity, their biological origin and both medical and industrial applications, this Perspective aims at highlighting hydroxamic acids as highly promising chelators in the fields of both medical and materials science. Furthermore, the state of the art in combining hydroxamic acids with a variety of polymer structures is discussed and a perspective regarding their vast potential at the interface of bioinorganic and polymer chemistry is given.
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Affiliation(s)
- Jennifer Keth
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, D-55124 Mainz, Germany
| | - Tobias Johann
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, D-55124 Mainz, Germany
| | - Holger Frey
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, D-55124 Mainz, Germany
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32
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Ben Said L, Emond-Rheault JG, Soltani S, Telhig S, Zirah S, Rebuffat S, Diarra MS, Goodridge L, Levesque RC, Fliss I. Phenomic and genomic approaches to studying the inhibition of multiresistant Salmonella enterica by microcin J25. Environ Microbiol 2020; 22:2907-2920. [PMID: 32363677 DOI: 10.1111/1462-2920.15045] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 04/15/2020] [Accepted: 04/25/2020] [Indexed: 12/22/2022]
Abstract
In livestock production, antibiotics are used to promote animal growth, control infections and thereby increase profitability. This practice has led to the emergence of multiresistant bacteria such as Salmonella, of which some serovars are disseminated in the environment. The objective of this study is to evaluate microcin J25 as an inhibitor of Salmonella enterica serovars of various origins including human, livestock and food. Among the 116 isolates tested, 37 (31.8%) were found resistant to at least one antibiotic, and 28 were multiresistant with 19 expressing the penta-resistant phenotype ACSSuT. Microcin J25 inhibited all isolates, with minimal inhibitory concentration values ranging from 0.06 μg/ml (28.4 nM) to 400 μg/ml (189 μM). Interestingly, no cross-resistance was found between microcin J25 and antibiotics. Multiple sequence alignments of genes encoding for the different proteins involved in the recognition and transport of microcin J25 showed that only ferric-hydroxamate uptake is an essential determinant for susceptibility of S. enterica to microcin J25. Examination of Salmonella strains exposed to microcin J25 by transmission electronic microscopy showed for the first-time involvement of a pore formation mechanism. Microcin J25 was a strong inhibitor of several multiresistant isolates of Salmonella and may have a great potential as an alternative to antibiotics.
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Affiliation(s)
- Laila Ben Said
- Institute of Nutrition and Functional Foods, Université Laval, Québec, Quebec, G1V 0A6, Canada
| | | | - Samira Soltani
- Institute of Nutrition and Functional Foods, Université Laval, Québec, Quebec, G1V 0A6, Canada
| | - Sofiane Telhig
- Institute of Nutrition and Functional Foods, Université Laval, Québec, Quebec, G1V 0A6, Canada.,Muséum National d'Histoire Naturelle, Centre National de la Recherche Scientifique, Laboratory of Communication Molecules and Adaptation of Micro-organisms, UMR 7245 CNRS-MNHN, Paris, CP 54, 57 rue Cuvier 75005, France
| | - Séverine Zirah
- Muséum National d'Histoire Naturelle, Centre National de la Recherche Scientifique, Laboratory of Communication Molecules and Adaptation of Micro-organisms, UMR 7245 CNRS-MNHN, Paris, CP 54, 57 rue Cuvier 75005, France
| | - Sylvie Rebuffat
- Muséum National d'Histoire Naturelle, Centre National de la Recherche Scientifique, Laboratory of Communication Molecules and Adaptation of Micro-organisms, UMR 7245 CNRS-MNHN, Paris, CP 54, 57 rue Cuvier 75005, France
| | - Moussa Sory Diarra
- Guelph Research and Development Center, Agriculture and Agri-Food Canada, 93 Stone Road West, Guelph, Ontario, N1G 5C9, Canada
| | - Lawrence Goodridge
- Department of Food Science and Agriculture, McGill University, Ste Anne de Bellevue, Québec, Quebec, H9X3V9, Canada
| | - Roger C Levesque
- Institute of Integrative Biology and Systems, Université Laval, QC, Québec, G1V 0A6, Canada
| | - Ismail Fliss
- Institute of Nutrition and Functional Foods, Université Laval, Québec, Quebec, G1V 0A6, Canada
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33
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Grinter R, Lithgow T. The crystal structure of the TonB-dependent transporter YncD reveals a positively charged substrate-binding site. Acta Crystallogr D Struct Biol 2020; 76:484-495. [PMID: 32355044 PMCID: PMC7193533 DOI: 10.1107/s2059798320004398] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 03/31/2020] [Indexed: 11/10/2022] Open
Abstract
The outer membrane of Gram-negative bacteria is highly impermeable to hydrophilic molecules of larger than 600 Da, protecting these bacteria from toxins present in the environment. In order to transport nutrients across this impermeable membrane, Gram-negative bacteria utilize a diverse family of outer-membrane proteins called TonB-dependent transporters. The majority of the members of this family transport iron-containing substrates. However, it is becoming increasingly clear that TonB-dependent transporters target chemically diverse substrates. In this work, the structure and phylogenetic distribution of the TonB-dependent transporter YncD are investigated. It is shown that while YncD is present in some enteropathogens, including Escherichia coli and Salmonella spp., it is also widespread in Gammaproteobacteria and Betaproteobacteria of environmental origin. The structure of YncD was determined, showing that despite a distant evolutionary relationship, it shares structural features with the ferric citrate transporter FecA, including a compact positively charged substrate-binding site. Despite these shared features, it is shown that YncD does not contribute to the growth of E. coli in pure culture under iron-limiting conditions or with ferric citrate as an iron source. Previous studies of transcriptional regulation in E. coli show that YncD is not induced under iron-limiting conditions and is unresponsive to the ferric uptake regulator (Fur). These observations, combined with the data presented here, suggest that YncD is not responsible for the transport of an iron-containing substrate.
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Affiliation(s)
- Rhys Grinter
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC 3800, Australia
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Trevor Lithgow
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC 3800, Australia
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34
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Li Z, Chinnasamy S, Zhang Y, Wei DQ. Molecular dynamics simulation and binding free energy calculations of microcin J25 binding to the FhuA receptor. J Biomol Struct Dyn 2020; 39:2585-2594. [DOI: 10.1080/07391102.2020.1751293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Zhenhua Li
- State Key Laboratory of Microbial Metabolism and College of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Sathishkumar Chinnasamy
- State Key Laboratory of Microbial Metabolism and College of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Yonghong Zhang
- Chongqing Research Center for Pharmaceutical Engineering, College of Pharmacy, Chongqing Medical University, Chongqing, China
| | - Dong-Qing Wei
- State Key Laboratory of Microbial Metabolism and College of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
- Center of Interdisciplinary Science-Computational Life Sciences, College of Food Science and Engineering, Henan University of Technology, Zhengzhou High-tech Industrial Development Zone, Zhengzhou, Henan, China
- Peng Cheng Laboratory, Shenzhen, Guangdong, P.R China
- Ministry of Education, Joint Laboratory of International Cooperation in Metabolic and Developmental Sciences, P.R China
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35
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Engineered P450 BM3 and cpADH5 coupled cascade reaction for β-oxo fatty acid methyl ester production in whole cells. Enzyme Microb Technol 2020; 138:109555. [PMID: 32527525 DOI: 10.1016/j.enzmictec.2020.109555] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 03/23/2020] [Accepted: 03/24/2020] [Indexed: 01/01/2023]
Abstract
Hydroxy- or ketone- functionalized fatty acid methyl esters (FAMEs) are important compounds for production of pharmaceuticals, vitamins, cosmetics or dietary supplements. Biocatalysis through enzymatic cascades has drawn attention to the efficient, sustainable, and greener synthetic processes. Furthermore, whole cell catalysts offer important advantages such as cofactor regeneration by cell metabolism, omission of protein purification steps and increased enzyme stability. Here, we report the first whole cell catalysis employing an engineered P450 BM3 variant and cpADH5 coupled cascade reaction for the biosynthesis of hydroxy- and keto-FAMEs. Firstly, P450 BM3 was engineered through the KnowVolution approach yielding P450 BM3 variant YE_M1_2, (R47S/Y51W/T235S/N239R/I401 M) which exhibited boosted performance toward methyl hexanoate. The initial oxidation rate of YE_M1_2 toward methyl hexanoate was determined to be 23-fold higher than the wild type enzyme and a 1.5-fold increase in methyl 3-hydroxyhexanoate production was obtained (YE_M1_2; 2.75 mM and WT; 1.8 mM). Subsequently, the whole cell catalyst for the synthesis of methyl 3-hydroxyhexanoate and methyl 3-oxohexanoate was constructed by combining the engineered P450 BM3 and cpADH5 variants in an artificial operon. A 2.06 mM total product formation was achieved by the whole cell catalyst including co-expressed channel protein, FhuA and co-solvent addition. Moreover, the generated whole cell biocatalyst also accepted methyl valerate, methyl heptanoate as well as methyl octanoate as substrates and yielded ω-1 ketones as the main product.
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36
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Ying YL, Wang J, Leach AR, Jiang Y, Gao R, Xu C, Edwards MA, Pendergast AD, Ren H, Weatherly CKT, Wang W, Actis P, Mao L, White HS, Long YT. Single-entity electrochemistry at confined sensing interfaces. Sci China Chem 2020. [DOI: 10.1007/s11426-020-9716-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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37
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Majumdar A, Trinh V, Moore KJ, Smallwood CR, Kumar A, Yang T, Scott DC, Long NJ, Newton SM, Klebba PE. Conformational rearrangements in the N-domain of Escherichia coli FepA during ferric enterobactin transport. J Biol Chem 2020; 295:4974-4984. [PMID: 32098871 DOI: 10.1074/jbc.ra119.011850] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 02/14/2020] [Indexed: 11/06/2022] Open
Abstract
The Escherichia coli outer membrane receptor FepA transports ferric enterobactin (FeEnt) by an energy- and TonB-dependent, but otherwise a mechanistically undetermined process involving its internal 150-residue N-terminal globular domain (N-domain). We genetically introduced pairs of Cys residues in different regions of the FepA tertiary structure, with the potential to form disulfide bonds. These included Cys pairs on adjacent β-strands of the N-domain (intra-N) and Cys pairs that bridged the external surface of the N-domain to the interior of the C-terminal transmembrane β-barrel (inter-N-C). We characterized FeEnt uptake by these mutants with siderophore nutrition tests, [59Fe]Ent binding and uptake experiments, and fluorescence decoy sensor assays. The three methods consistently showed that the intra-N disulfide bonds, which restrict conformational motion within the N-domain, prevented FeEnt uptake, whereas most inter-N-C disulfide bonds did not prevent FeEnt uptake. These outcomes indicate that conformational rearrangements must occur in the N terminus of FepA during FeEnt transport. They also argue against disengagement of the N-domain out of the channel as a rigid body and suggest instead that it remains within the transmembrane pore as FeEnt enters the periplasm.
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Affiliation(s)
- Aritri Majumdar
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506
| | - Vy Trinh
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019
| | - Kyle J Moore
- Department of Chemistry, Physics and Engineering, Cameron University, Lawton, Oklahoma 73505
| | | | - Ashish Kumar
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506
| | - Taihao Yang
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506
| | - Daniel C Scott
- Howard Hughes Medical Institute, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Noah J Long
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506
| | - Salete M Newton
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506
| | - Phillip E Klebba
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506
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38
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Wang J, Li MY, Yang J, Wang YQ, Wu XY, Huang J, Ying YL, Long YT. Direct Quantification of Damaged Nucleotides in Oligonucleotides Using an Aerolysin Single Molecule Interface. ACS CENTRAL SCIENCE 2020; 6:76-82. [PMID: 31989027 PMCID: PMC6978832 DOI: 10.1021/acscentsci.9b01129] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Indexed: 05/06/2023]
Abstract
DNA lesions such as metholcytosine(mC), 8-OXO-guanine (OG), inosine (I), etc. could cause genetic diseases. Identification of the varieties of lesion bases are usually beyond the capability of conventional DNA sequencing which is mainly designed to discriminate four bases only. Therefore, lesion detection remains a challenge due to massive varieties and less distinguishable readouts for structural variations at the molecular level. Moreover, standard amplification and labeling hardly work in DNA lesion detection. Herein, we designed a single molecule interface from the mutant aerolysin (K238Q), whose sensing region shows high compatibility to capture and then directly convert a minor lesion into distinguishable electrochemical readouts. Compared with previous single molecule sensing interfaces, the temporal resolution of the K238Q aerolysin nanopore is enhanced by two orders, which has the best sensing performance in all reported aerolysin nanopores. In this work, the novel K238Q could discriminate directly at least three types of lesions (mC, OG, I) without labeling and quantify modification sites under the mixed heterocomposition conditions of the oligonucleotide. Such a nanopore electrochemistry approach could be further applied to diagnose genetic diseases at high sensitivity.
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Affiliation(s)
- Jiajun Wang
- State
Key Laboratory of Analytical Chemistry for Life Science, School of
Chemistry and Chemical Engineering, Nanjing
University, 210023, Nanjing, China
- School
of Chemistry and Molecular Engineering, East China University of Science and Technology, 200237, Shanghai, China
| | - Meng-Yin Li
- State
Key Laboratory of Analytical Chemistry for Life Science, School of
Chemistry and Chemical Engineering, Nanjing
University, 210023, Nanjing, China
| | - Jie Yang
- School
of Chemistry and Molecular Engineering, East China University of Science and Technology, 200237, Shanghai, China
| | - Ya-Qian Wang
- School
of Chemistry and Molecular Engineering, East China University of Science and Technology, 200237, Shanghai, China
| | - Xue-Yuan Wu
- State
Key Laboratory of Analytical Chemistry for Life Science, School of
Chemistry and Chemical Engineering, Nanjing
University, 210023, Nanjing, China
- School
of Chemistry and Molecular Engineering, East China University of Science and Technology, 200237, Shanghai, China
| | - Jin Huang
- School
of Pharmacy, East China University of Science
and Technology, 200237, Shanghai, China
| | - Yi-Lun Ying
- State
Key Laboratory of Analytical Chemistry for Life Science, School of
Chemistry and Chemical Engineering, Nanjing
University, 210023, Nanjing, China
| | - Yi-Tao Long
- State
Key Laboratory of Analytical Chemistry for Life Science, School of
Chemistry and Chemical Engineering, Nanjing
University, 210023, Nanjing, China
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39
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Perruchon C, Vasileiadis S, Papadopoulou ES, Karpouzas DG. Genome-Based Metabolic Reconstruction Unravels the Key Role of B12 in Methionine Auxotrophy of an Ortho-Phenylphenol-Degrading Sphingomonas haloaromaticamans. Front Microbiol 2020; 10:3009. [PMID: 31998277 PMCID: PMC6970198 DOI: 10.3389/fmicb.2019.03009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Accepted: 12/16/2019] [Indexed: 12/30/2022] Open
Abstract
Auxotrophy to amino acids and vitamins is a common feature in the bacterial world shaping microbial communities through cross-feeding relations. The amino acid auxotrophy of pollutant-degrading bacteria could hamper their bioremediation potential, however, the underlying mechanisms of auxotrophy remain unexplored. We employed genome sequence-based metabolic reconstruction to identify potential mechanisms driving the amino acid auxotrophy of a Sphingomonas haloaromaticamans strain degrading the fungicide ortho-phenylphenol (OPP) and provided further verification for the identified mechanisms via in vitro bacterial assays. The analysis identified potential gaps in the biosynthesis of isoleucine, phenylalanine and tyrosine, while methionine biosynthesis was potentially effective, relying though in the presence of B12. Supplementation of the bacterium with the four amino acids in all possible combinations rescued its degrading capacity only with methionine. Genome sequence-based metabolic reconstruction and analysis suggested that the bacterium was incapable of de novo biosynthesis of B12 (missing genes for the construction of the corrin ring) but carried a complete salvage pathway for corrinoids uptake from the environment, transmembrane transportation and biosynthesis of B12. In line with this the bacterium maintained its degrading capacity and growth when supplied with environmentally relevant B12 concentrations (i.e., 0.1 ng ml–1). Using genome-based metabolic reconstruction and in vitro testing we unraveled the mechanism driving the auxotrophy of a pesticide-degrading S. haloaromaticamans. Further studies will investigate the corrinoids preferences of S. haloaromaticamans for optimum growth and OPP degradation.
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Affiliation(s)
- Chiara Perruchon
- Laboratory of Plant and Environmental Biotechnology, Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece
| | - Sotirios Vasileiadis
- Laboratory of Plant and Environmental Biotechnology, Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece
| | - Evangelia S Papadopoulou
- Laboratory of Plant and Environmental Biotechnology, Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece
| | - Dimitrios G Karpouzas
- Laboratory of Plant and Environmental Biotechnology, Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece
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40
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Genetic and structural determinants on iron assimilation pathways in the plant pathogen Xanthomonas citri subsp. citri and Xanthomonas sp. Braz J Microbiol 2019; 51:1219-1231. [PMID: 31848911 DOI: 10.1007/s42770-019-00207-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 12/06/2019] [Indexed: 10/25/2022] Open
Abstract
Iron is a vital nutrient to bacteria, not only in the basal metabolism but also for virulent species in infection and pathogenicity at their hosts. Despite its relevance, the role of iron in Xanthomonas citri infection, the etiological agent of citrus canker disease, is poorly understood in contrast to other pathogens, including other members of the Xanthomonas genus. In this review, we present iron assimilation pathways in X. citri including the ones for siderophore production and siderophore-iron assimilation, proven to be key factors to virulence in many organisms like Escherichia coli and Xanthomonas campestris. Based on classical iron-related proteins previously characterized in E. coli, Pseudomonas aeruginosa, and also Xanthomonadaceae, we identified orthologs in X. citri and evaluated their sequences, structural characteristics such as functional motifs, and residues that support their putative functions. Among the identified proteins are TonB-dependent receptors, periplasmic-binding proteins, active transporters, efflux pumps, and cytoplasmic enzymes. The role of each protein for the bacterium was analyzed and complemented with proteomics data previously reported. The global view of different aspects of iron regulation and nutrition in X. citri virulence and pathogenesis may help guide future investigations aiming the development of new drug targets against this important phytopathogen.
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41
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Grinter R, Lithgow T. The structure of the bacterial iron-catecholate transporter Fiu suggests that it imports substrates via a two-step mechanism. J Biol Chem 2019; 294:19523-19534. [PMID: 31712312 PMCID: PMC6926462 DOI: 10.1074/jbc.ra119.011018] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 11/06/2019] [Indexed: 12/12/2022] Open
Abstract
The ferric iron uptake (Fiu) transporter from Escherichia coli functions in the transport of iron–catecholate complexes across the bacterial outer membrane, providing the bacterium with iron, which is essential for growth. Recently it has become clear that Fiu also represents a liability for E. coli because its activity allows import of antimicrobial compounds that mimic catecholate. This inadvertent import suggests the potential utility of antimicrobial catechol siderophore mimetics in managing bacterial infections. However, to fully exploit these compounds, a detailed understanding of the mechanism of transport through Fiu and related transporters is required. To address this question, we determined the crystal structure of Fiu at 2.1–2.9 Å and analyzed its function in E. coli. Through analysis of the Fiuo crystal structure, in combination with in silico docking and mutagenesis, we provide insight into how Fiu and related transporters bind catecholate in a surface-exposed cavity. Moreover, through determination of the structure of Fiu in multiple crystal states, we revealed the presence of a large, selectively gated cavity in the interior of this transporter. This chamber is large enough to accommodate the Fiu substrate and may allow import of substrates via a two-step mechanism. This would avoid channel formation through the transporter and inadvertent import of toxic molecules. As Fiu and its homologs are the targets of substrate-mimicking antibiotics, these results may assist in the development of these compounds.
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Affiliation(s)
- Rhys Grinter
- School of Biological Sciences, Monash University, Clayton, 3800 Victoria, Australia .,Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, 3800 Victoria, Australia
| | - Trevor Lithgow
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, 3800 Victoria, Australia
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42
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Thakur AK, Movileanu L. Single-Molecule Protein Detection in a Biofluid Using a Quantitative Nanopore Sensor. ACS Sens 2019; 4:2320-2326. [PMID: 31397162 DOI: 10.1021/acssensors.9b00848] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Protein detection in complex biological fluids has wide-ranging significance across proteomics and molecular medicine. Existing detectors cannot readily distinguish between specific and nonspecific interactions in a heterogeneous solution. Here, we show that this daunting shortcoming can be overcome by using a protein bait-containing biological nanopore in mammalian serum. The capture and release events of a protein analyte by the tethered protein bait occur outside the nanopore and are accompanied by uniform current openings. Conversely, nonspecific pore penetrations by nontarget components of serum, which take place inside the nanopore, are featured by irregular current blockades. As a result of this unique peculiarity of the readout between specific protein captures and nonspecific pore penetration events, our selective sensor can quantitatively sample proteins at single-molecule precision in a manner distinctive from those employed by prevailing methods. Because our sensor can be integrated into nanofluidic devices and coupled with high-throughput technologies, our approach will have a transformative impact in protein identification and quantification in clinical isolates for disease prognostics and diagnostics.
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Affiliation(s)
- Avinash Kumar Thakur
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, United States
- Structural Biology, Biochemistry, and Biophysics Program, Syracuse University, 111 College Place, Syracuse, New York 13244-4100, United States
| | - Liviu Movileanu
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, United States
- Structural Biology, Biochemistry, and Biophysics Program, Syracuse University, 111 College Place, Syracuse, New York 13244-4100, United States
- Department of Biomedical and Chemical Engineering, Syracuse University, 329 Link Hall, Syracuse, New York 13244, United States
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43
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Mirzaei Garakani T, Liu Z, Glebe U, Gehrmann J, Lazar J, Mertens MAS, Möller M, Hamzelui N, Zhu L, Schnakenberg U, Böker A, Schwaneberg U. In Situ Monitoring of Membrane Protein Insertion into Block Copolymer Vesicle Membranes and Their Spreading via Potential-Assisted Approach. ACS APPLIED MATERIALS & INTERFACES 2019; 11:29276-29289. [PMID: 31329408 DOI: 10.1021/acsami.9b09302] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Synthosomes are polymer vesicles with transmembrane proteins incorporated into block copolymer membranes. They have been used for selective transport in or out of the vesicles as well as catalysis inside the compartments. However, both the insertion process of the membrane protein, forming nanopores, and the spreading of the vesicles on planar substrates to form solid-supported biomimetic membranes have been rarely studied yet. Herein, we address these two points and, first, shed light on the real-time monitoring of protein insertion via isothermal titration calorimetry. Second, the spreading process on different solid supports, namely, SiO2, glass, and gold, via different techniques like spin- and dip-coating as well as a completely new approach of potential-assisted spreading on gold surfaces was studied. While inhomogeneous layers occur via traditional methods, our proposed potential-assisted strategy to induce adsorption of positively charged vesicles by applying negative potential on the electrode leads to remarkable vesicle spreading and their further fusion to form more homogeneous planar copolymer films on gold. The polymer vesicles in our study are formed from amphiphilic copolymers poly(2-methyl oxazoline)-block-poly(dimethylsiloxane)-block-poly(2-methyl oxazoline) (PMOXA-b-PDMS-b-PMOXA). Engineered variants of the transmembrane protein ferric hydroxamate uptake protein component A (FhuA), one of the largest β-barrel channel proteins, are used as model nanopores. The incorporation of FhuA Δ1-160 is shown to facilitate the vesicle spreading process further. Moreover, high accessibility of cysteine inside the channel was proven by linkage of a fluorescent dye inside the engineered variant FhuA ΔCVFtev and hence preserved functionality of the channels after spreading. The porosity and functionality of the spread synthosomes on the gold plates have been examined by studying the passive ion transport response in the presence of Li+ and ClO4- ions and electrochemical impedance spectroscopy analysis. Our approach to form solid-supported biomimetic membranes via the potential-assisted strategy could be important for the development of new (bio-) sensors and membranes.
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Affiliation(s)
- Tayebeh Mirzaei Garakani
- Institute of Biotechnology , RWTH Aachen University , Worringer Weg 3 , D-52074 Aachen , Germany
- DWI - Leibniz Institute for Interactive Materials , Forckenbeckstraße 50 , D-52074 , Aachen , Germany
| | - Zhanzhi Liu
- Institute of Biotechnology , RWTH Aachen University , Worringer Weg 3 , D-52074 Aachen , Germany
| | - Ulrich Glebe
- Fraunhofer Institute for Applied Polymer Research IAP , Geiselbergstraße 69 , 14476 Potsdam -Golm, Germany
- Chair of Polymer Materials and Polymer Technologies, Institute of Chemistry , University of Potsdam , Karl-Liebknecht-Str. 24-25 , 14476 Potsdam -Golm, Germany
| | - Julia Gehrmann
- Institute of Biotechnology , RWTH Aachen University , Worringer Weg 3 , D-52074 Aachen , Germany
| | - Jaroslav Lazar
- Institute of Materials in Electrical Engineering 1 , RWTH Aachen University , Sommerfeldstraße 24 , 52074 Aachen , Germany
| | | | - Mieke Möller
- Institute of Biotechnology , RWTH Aachen University , Worringer Weg 3 , D-52074 Aachen , Germany
| | - Niloofar Hamzelui
- Institute of Biotechnology , RWTH Aachen University , Worringer Weg 3 , D-52074 Aachen , Germany
| | - Leilei Zhu
- Institute of Biotechnology , RWTH Aachen University , Worringer Weg 3 , D-52074 Aachen , Germany
| | - Uwe Schnakenberg
- Institute of Materials in Electrical Engineering 1 , RWTH Aachen University , Sommerfeldstraße 24 , 52074 Aachen , Germany
| | - Alexander Böker
- Fraunhofer Institute for Applied Polymer Research IAP , Geiselbergstraße 69 , 14476 Potsdam -Golm, Germany
- Chair of Polymer Materials and Polymer Technologies, Institute of Chemistry , University of Potsdam , Karl-Liebknecht-Str. 24-25 , 14476 Potsdam -Golm, Germany
| | - Ulrich Schwaneberg
- Institute of Biotechnology , RWTH Aachen University , Worringer Weg 3 , D-52074 Aachen , Germany
- DWI - Leibniz Institute for Interactive Materials , Forckenbeckstraße 50 , D-52074 , Aachen , Germany
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44
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Moynié L, Milenkovic S, Mislin GLA, Gasser V, Malloci G, Baco E, McCaughan RP, Page MGP, Schalk IJ, Ceccarelli M, Naismith JH. The complex of ferric-enterobactin with its transporter from Pseudomonas aeruginosa suggests a two-site model. Nat Commun 2019; 10:3673. [PMID: 31413254 PMCID: PMC6694100 DOI: 10.1038/s41467-019-11508-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 07/16/2019] [Indexed: 11/17/2022] Open
Abstract
Bacteria use small molecules called siderophores to scavenge iron. Siderophore-Fe3+ complexes are recognised by outer-membrane transporters and imported into the periplasm in a process dependent on the inner-membrane protein TonB. The siderophore enterobactin is secreted by members of the family Enterobacteriaceae, but many other bacteria including Pseudomonas species can use it. Here, we show that the Pseudomonas transporter PfeA recognises enterobactin using extracellular loops distant from the pore. The relevance of this site is supported by in vivo and in vitro analyses. We suggest there is a second binding site deeper inside the structure and propose that correlated changes in hydrogen bonds link binding-induced structural re-arrangements to the structural adjustment of the periplasmic TonB-binding motif.
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Affiliation(s)
- Lucile Moynié
- Division of Structural Biology, Wellcome Trust Centre of Human Genomics, 7 Roosevelt Drive, Oxford, OX3 7BN, UK
- The Research Complex at Harwell, Harwell Campus, Oxfordshire, OX11 0FA, UK
- The Rosalind Franklin Institute, Didcot, OX11 0FA, UK
| | - Stefan Milenkovic
- Department of Physics, University of Cagliari, Cittadella Universitaria, SP Monserrato-Sestu Km 0.700, Monserrato, 09042, Italy
| | - Gaëtan L A Mislin
- Université de Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, Illkirch, F-67413, Strasbourg, France
- CNRS, UMR7242, ESBS, Bld Sébastien Brant, Illkirch, F-67413, Strasbourg, France
| | - Véronique Gasser
- Université de Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, Illkirch, F-67413, Strasbourg, France
- CNRS, UMR7242, ESBS, Bld Sébastien Brant, Illkirch, F-67413, Strasbourg, France
| | - Giuliano Malloci
- Department of Physics, University of Cagliari, Cittadella Universitaria, SP Monserrato-Sestu Km 0.700, Monserrato, 09042, Italy
| | - Etienne Baco
- Université de Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, Illkirch, F-67413, Strasbourg, France
- CNRS, UMR7242, ESBS, Bld Sébastien Brant, Illkirch, F-67413, Strasbourg, France
| | | | - Malcolm G P Page
- Department of Life Sciences & Chemistry, Campus Ring 1, Bremen, 28759, Germany
| | - Isabelle J Schalk
- Université de Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, Illkirch, F-67413, Strasbourg, France.
- Istituto Officina dei Materiali-CNR, Cittadella Universitaria, Monserrato, 09042, Italy.
| | - Matteo Ceccarelli
- Department of Physics, University of Cagliari, Cittadella Universitaria, SP Monserrato-Sestu Km 0.700, Monserrato, 09042, Italy.
- Istituto Officina dei Materiali-CNR, Cittadella Universitaria, Monserrato, 09042, Italy.
| | - James H Naismith
- Division of Structural Biology, Wellcome Trust Centre of Human Genomics, 7 Roosevelt Drive, Oxford, OX3 7BN, UK.
- The Research Complex at Harwell, Harwell Campus, Oxfordshire, OX11 0FA, UK.
- The Rosalind Franklin Institute, Didcot, OX11 0FA, UK.
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45
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Anand D, Dhoke GV, Gehrmann J, Garakani TM, Davari MD, Bocola M, Zhu L, Schwaneberg U. Chiral separation of d/l-arginine with whole cells through an engineered FhuA nanochannel. Chem Commun (Camb) 2019; 55:5431-5434. [PMID: 30916680 DOI: 10.1039/c9cc00154a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Downstream processing to obtain enantiopure compounds from a racemic mixture relies mainly on crystallization. Natural transporters can specifically translocate enantiomers through membranes. Here a β-barrel transmembrane protein FhuA is re-engineered into a chiral channel protein (FhuAF4) to resolve racemic mixtures of d-/l-arginine. The engineered FhuAF4 variant exhibits an enantioselectivity (E-value) of 1.92 and an enantiomeric excess percentage (ee%) of 23.91 at 52.39% conversion. OmniChange mutant libraries at the computationally identified "filter-regions" likely help to identify FhuA variants for enantiomeric separation of other compounds.
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Affiliation(s)
- Deepak Anand
- Institute of Biotechnology, RWTH Aachen University Worringer Weg 3, D-52074 Aachen, Germany.
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46
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Wilson J, Sarthak K, Si W, Gao L, Aksimentiev A. Rapid and Accurate Determination of Nanopore Ionic Current Using a Steric Exclusion Model. ACS Sens 2019; 4:634-644. [PMID: 30821441 DOI: 10.1021/acssensors.8b01375] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Nanopore sensing has emerged as a versatile approach to detection and identification of biomolecules. Presently, researchers rely on experience and intuition for choosing or modifying the nanopores to detect a target analyte. The field would greatly benefit from a computational method that could relate the atomic-scale geometry of the nanopores and analytes to the blockade nanopore currents they produce. Existing computational methods are either computationally too expensive to be used routinely in experimental laboratories or not sensitive enough to account for the atomic structure of the pore and the analytes. Here, we demonstrate a robust and inexpensive computational approach-the steric exclusion model (SEM) of nanopore conductance-that is orders of magnitude more efficient than all-atom MD and yet is sensitive enough to account for the atomic structure of the nanopore and the analyte. The method combines the computational efficiency of a finite element solver with the atomic precision of a nanopore conductance map to yield unprecedented speed and accuracy of ionic current prediction. We validate our SEM approach through comparison with the current blockades computed using the all-atom molecular dynamics method for a range of proteins confined to a solid-state nanopore, biological channels embedded in a lipid bilayer membranes, and blockade currents produced by DNA homopolymers in MspA. We illustrate potential applications of SEM by computing blockade currents produced by nucleosome proteins in a solid-state nanopore, individual amino acids in MspA, and by testing the effect of point mutations on amino acid distinguishability. We expect our SEM approach to become an integral part of future development of the nanopore sensing field.
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Affiliation(s)
| | | | - Wei Si
- Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments and School of Mechanical Engineering, Southeast University, Nanjing, 210096, China
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47
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Ivanov AS, Parker BF, Zhang Z, Aguila B, Sun Q, Ma S, Jansone-Popova S, Arnold J, Mayes RT, Dai S, Bryantsev VS, Rao L, Popovs I. Siderophore-inspired chelator hijacks uranium from aqueous medium. Nat Commun 2019; 10:819. [PMID: 30778071 PMCID: PMC6379418 DOI: 10.1038/s41467-019-08758-1] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 01/25/2019] [Indexed: 01/07/2023] Open
Abstract
Over millennia, nature has evolved an ability to selectively recognize and sequester specific metal ions by employing a wide variety of supramolecular chelators. Iron-specific molecular carriers—siderophores—are noteworthy for their structural elegance, while exhibiting some of the strongest and most selective binding towards a specific metal ion. Development of simple uranyl (UO22+) recognition motifs possessing siderophore-like selectivity, however, presents a challenge. Herein we report a comprehensive theoretical, crystallographic and spectroscopic studies on the UO22+ binding with a non-toxic siderophore-inspired chelator, 2,6-bis[hydroxy(methyl)amino]-4-morpholino-1,3,5-triazine (H2BHT). The optimal pKa values and structural preorganization endow H2BHT with one of the highest uranyl binding affinity and selectivity among molecular chelators. The results of small-molecule standards are validated by a proof-of-principle development of the H2BHT-functionalized polymeric adsorbent material that affords high uranium uptake capacity even in the presence of competing vanadium (V) ions in aqueous medium. Development of simple uranyl recognition motifs possessing siderophore-like binding strength and selectivity presents a challenge. Here the authors show a comprehensive theoretical and experimental study on uranyl binding with a polymeric adsorbent material decorated with a non-toxic siderophore inspired small molecule chelator.
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Affiliation(s)
| | - Bernard F Parker
- Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,University of California, Berkeley, CA, 94720, USA
| | - Zhicheng Zhang
- Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | | | - Qi Sun
- University of South Florida, Tampa, FL, 33620, USA
| | - Shengqian Ma
- University of South Florida, Tampa, FL, 33620, USA
| | | | - John Arnold
- Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,University of California, Berkeley, CA, 94720, USA
| | | | - Sheng Dai
- Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | | | - Linfeng Rao
- Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
| | - Ilja Popovs
- Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
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48
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Zupok A, Iobbi-Nivol C, Méjean V, Leimkühler S. The regulation of Moco biosynthesis and molybdoenzyme gene expression by molybdenum and iron in bacteria. Metallomics 2019; 11:1602-1624. [DOI: 10.1039/c9mt00186g] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The regulation of the operons involved in Moco biosynthesis is dependent on the availability of Fe–S clusters in the cell.
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Affiliation(s)
- Arkadiusz Zupok
- University of Potsdam
- Institute of Biochemistry and Biology
- Molecular Enzymology
- Potsdam-Golm
- Germany
| | - Chantal Iobbi-Nivol
- Aix-Marseille Université
- Institut de Microbiologie de la Méditerranée
- Laboratoire de Bioénergétique et Ingénierie des Protéines
- Centre National de la Recherche Scientifique
- Marseille
| | - Vincent Méjean
- Aix-Marseille Université
- Institut de Microbiologie de la Méditerranée
- Laboratoire de Bioénergétique et Ingénierie des Protéines
- Centre National de la Recherche Scientifique
- Marseille
| | - Silke Leimkühler
- University of Potsdam
- Institute of Biochemistry and Biology
- Molecular Enzymology
- Potsdam-Golm
- Germany
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49
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Moynié L, Serra I, Scorciapino MA, Oueis E, Page MG, Ceccarelli M, Naismith JH. Preacinetobactin not acinetobactin is essential for iron uptake by the BauA transporter of the pathogen Acinetobacter baumannii. eLife 2018; 7:42270. [PMID: 30558715 PMCID: PMC6300358 DOI: 10.7554/elife.42270] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 12/02/2018] [Indexed: 01/05/2023] Open
Abstract
New strategies are urgently required to develop antibiotics. The siderophore uptake system has attracted considerable attention, but rational design of siderophore antibiotic conjugates requires knowledge of recognition by the cognate outer-membrane transporter. Acinetobacter baumannii is a serious pathogen, which utilizes (pre)acinetobactin to scavenge iron from the host. We report the structure of the (pre)acinetobactin transporter BauA bound to the siderophore, identifying the structural determinants of recognition. Detailed biophysical analysis confirms that BauA recognises preacinetobactin. We show that acinetobactin is not recognised by the protein, thus preacinetobactin is essential for iron uptake. The structure shows and NMR confirms that under physiological conditions, a molecule of acinetobactin will bind to two free coordination sites on the iron preacinetobactin complex. The ability to recognise a heterotrimeric iron-preacinetobactin-acinetobactin complex may rationalize contradictory reports in the literature. These results open new avenues for the design of novel antibiotic conjugates (trojan horse) antibiotics.
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Affiliation(s)
- Lucile Moynié
- Division of Structural Biology, Wellcome Trust Centre of Human Genomics, Oxford, England.,Research Complex at Harwell, Rutherford Laboratory, Didcot, England
| | - Ilaria Serra
- Department of Physics, University of Cagliari, Cagliari, Italy.,Department of Chemical and Geological Sciences, University of Cagliari, Cagliari, Italy
| | - Mariano A Scorciapino
- Department of Physics, University of Cagliari, Cagliari, Italy.,Department of Chemical and Geological Sciences, University of Cagliari, Cagliari, Italy
| | - Emilia Oueis
- Biomedical Sciences Research Complex, The University of St Andrews, Scotland, United Kingdom
| | - Malcolm Gp Page
- Department of Life Sciences and Chemistry, Jacobs University, Bremen, Germany
| | | | - James H Naismith
- Division of Structural Biology, Wellcome Trust Centre of Human Genomics, Oxford, England.,Research Complex at Harwell, Rutherford Laboratory, Didcot, England.,The Rosalind Franklin Institute, Didcot, England
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50
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Thakur AK, Movileanu L. Real-time measurement of protein-protein interactions at single-molecule resolution using a biological nanopore. Nat Biotechnol 2018; 37:nbt.4316. [PMID: 30531896 PMCID: PMC6557705 DOI: 10.1038/nbt.4316] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 11/11/2018] [Indexed: 12/30/2022]
Abstract
Protein-protein interactions (PPIs) are essential for many cellular processes. However, transient PPIs are difficult to measure at high throughput or in complex biological fluids using existing methods. We engineered a genetically encoded sensor for real-time sampling of transient PPIs at single-molecule resolution. Our sensor comprises a truncated outer membrane protein pore, a flexible tether, a protein receptor and a peptide adaptor. When a protein ligand present in solution binds to the receptor, reversible capture and release events of the receptor can be measured as current transitions between two open substates of the pore. Notably, the binding and release of the receptor by a protein ligand can be unambiguously discriminated in a complex sample containing fetal bovine serum. Our selective nanopore sensor could be applied for single-molecule protein detection, could form the basis for a nanoproteomics platform or might be adapted to build tools for protein profiling and biomarker discovery.
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Affiliation(s)
- Avinash Kumar Thakur
- Department of Physics, Syracuse University, Syracuse, New York, USA
- Structural Biology, Biochemistry, and Biophysics Program, Syracuse University, Syracuse, New York, USA
| | - Liviu Movileanu
- Department of Physics, Syracuse University, Syracuse, New York, USA
- Structural Biology, Biochemistry, and Biophysics Program, Syracuse University, Syracuse, New York, USA
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York, USA
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