1
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Campbell E, Luxton T, Kohl D, Goodchild SA, Walti C, Jeuken LJC. Chimeric Protein Switch Biosensors. Adv Biochem Eng Biotechnol 2024. [PMID: 38273207 DOI: 10.1007/10_2023_241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2024]
Abstract
Rapid detection of protein and small-molecule analytes is a valuable technique across multiple disciplines, but most in vitro testing of biological or environmental samples requires long, laborious processes and trained personnel in laboratory settings, leading to long wait times for results and high expenses. Fusion of recognition with reporter elements has been introduced to detection methods such as enzyme-linked immunoassays (ELISA), with enzyme-conjugated secondary antibodies removing one of the many incubation and wash steps. Chimeric protein switch biosensors go further and provide a platform for homogenous mix-and-read assays where long wash and incubation steps are eradicated from the process. Chimeric protein switch biosensors consist of an enzyme switch (the reporter) coupled to a recognition element, where binding of the analyte results in switching the activity of the reporter enzyme on or off. Several chimeric protein switch biosensors have successfully been developed for analytes ranging from small molecule drugs to large protein biomarkers. There are two main formats of chimeric protein switch biosensor developed, one-component and multi-component, and these formats exhibit unique advantages and disadvantages. Genetically fusing a recognition protein to the enzyme switch has many advantages in the production and performance of the biosensor. A range of immune and synthetic binding proteins have been developed as alternatives to antibodies, including antibody mimetics or antibody fragments. These are mainly small, easily manipulated proteins and can be genetically fused to a reporter for recombinant expression or manipulated to allow chemical fusion. Here, aspects of chimeric protein switch biosensors will be reviewed with a comparison of different classes of recognition elements and switching mechanisms.
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Affiliation(s)
- Emma Campbell
- School of Biomedical Sciences, University of Leeds, Leeds, UK
| | - Timothy Luxton
- School of Biomedical Sciences, University of Leeds, Leeds, UK
| | - Declan Kohl
- School of Biomedical Sciences, University of Leeds, Leeds, UK
| | | | - Christoph Walti
- School of Electronic and Electrical Engineering, University of Leeds, Leeds, UK
| | - Lars J C Jeuken
- School of Biomedical Sciences, University of Leeds, Leeds, UK.
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands.
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2
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Campbell E, Adamson H, Luxton T, Tiede C, Wälti C, Tomlinson DC, Jeuken LJC. Therapeutic drug monitoring of immunotherapies with novel Affimer-NanoBiT sensor construct. Sens Diagn 2024; 3:104-111. [PMID: 38249540 PMCID: PMC10795742 DOI: 10.1039/d3sd00126a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 10/23/2023] [Indexed: 01/23/2024]
Abstract
Concentration-therapeutic efficacy relationships have been observed for several therapeutic monoclonal antibodies (TmAb), where low circulating levels can result in ineffective treatment and high concentrations can cause adverse reactions. Rapid therapeutic drug monitoring (TDM) of TmAb drugs would provide the opportunity to adjust an individual patient's dosing regimen to improve treatment results. However, TDM for immunotherapies is currently limited to centralised testing methods with long sample-collection to result timeframes. Here, we show four point-of-care (PoC) TmAb biosensors by combining anti-idiotypic Affimer proteins and NanoBiT split luciferase technology at a molecular level to provide a platform for rapid quantification (<10 minutes) for four clinically relevant TmAb (rituximab, adalimumab, ipilimumab and trastuzumab). The rituximab sensor performed best with 4 pM limit of detection (LoD) and a quantifiable range between 8 pM-2 nM with neglectable matrix effects in serum up to 1%. After dilution of serum samples, the resulting quantifiable range for all four sensors falls within the clinically relevant range and compares favourably with the sensitivity and/or time-to-result of current ELISA standards. Further development of these sensors into a PoC test may improve treatment outcome and quality of life for patients receiving immunotherapy.
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Affiliation(s)
- Emma Campbell
- School of Biomedical Science, University of Leeds Leeds LS2 9JT UK
- Astbury Centre for Structural Molecular Biology, University of Leeds LS2 9JT UK
| | - Hope Adamson
- School of Biomedical Science, University of Leeds Leeds LS2 9JT UK
- Astbury Centre for Structural Molecular Biology, University of Leeds LS2 9JT UK
| | - Timothy Luxton
- School of Biomedical Science, University of Leeds Leeds LS2 9JT UK
- Astbury Centre for Structural Molecular Biology, University of Leeds LS2 9JT UK
| | - Christian Tiede
- Astbury Centre for Structural Molecular Biology, University of Leeds LS2 9JT UK
- School of Molecular and Cellular Biology, University of Leeds Leeds LS2 9JT UK
| | - Christoph Wälti
- School of Electronic and Electrical Engineering, University of Leeds LS2 9JT UK
| | - Darren C Tomlinson
- Astbury Centre for Structural Molecular Biology, University of Leeds LS2 9JT UK
- School of Molecular and Cellular Biology, University of Leeds Leeds LS2 9JT UK
| | - Lars J C Jeuken
- School of Biomedical Science, University of Leeds Leeds LS2 9JT UK
- Astbury Centre for Structural Molecular Biology, University of Leeds LS2 9JT UK
- Leiden Institute of Chemistry, Leiden University PO Box 9502 2300 RA Leiden The Netherlands
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3
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Casadevall C, Lage A, Mu M, Greer HF, Antón-García D, Butt JN, Jeuken LJC, Watson GW, García-Melchor M, Reisner E. Size-dependent activity of carbon dots for photocatalytic H 2 generation in combination with a molecular Ni cocatalyst. Nanoscale 2023; 15:15775-15784. [PMID: 37740380 PMCID: PMC10551879 DOI: 10.1039/d3nr03300g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 08/27/2023] [Indexed: 09/24/2023]
Abstract
Carbon dots (CDs) are low-cost light-absorbers in photocatalytic multicomponent systems, but their wide size distribution has hampered rational design and the identification of the factors that lead to their best performance. To address this challenge, we report herein the use of gel filtration size exclusion chromatography to separate amorphous, graphitic, and graphitic N-doped CDs depending on their lateral size to study the effect of their size on photocatalytic H2 evolution with a DuBois-type Ni cocatalyst. Transmission electron microscopy and dynamic light scattering confirm the size-dependent separation of the CDs, whereas UV-vis and fluorescence spectroscopy of the more monodisperse fractions show a distinct response which computational modelling attributes to a complex interplay between CD size and optical properties. A size-dependent effect on the photocatalytic H2 evolution performance of the CDs in combination with a molecular Ni cocatalyst is demonstrated with a maximum activity at approximately 2-3 nm CD diameter. Overall, size separation leads to a two-fold increase in the specific photocatalytic activity for H2 evolution using the monodisperse CDs compared to the as synthesized polydisperse samples, highlighting the size-dependent effect on photocatalytic performance.
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Affiliation(s)
- Carla Casadevall
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
| | - Ava Lage
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
| | - Manting Mu
- School of Chemistry, Trinity College Dublin, College Green, Dublin 2, Ireland
| | - Heather F Greer
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
| | - Daniel Antón-García
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
| | - Julea N Butt
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Lars J C Jeuken
- Leiden Institute of Chemistry, Leiden University, PO Box 9502, 2300 RA, Leiden, The Netherlands
| | - Graeme W Watson
- School of Chemistry, Trinity College Dublin, College Green, Dublin 2, Ireland
| | - Max García-Melchor
- School of Chemistry, Trinity College Dublin, College Green, Dublin 2, Ireland
- CRANN and AMBER Research Centres, College Green, Dublin 2, Ireland.
| | - Erwin Reisner
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
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4
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Campbell E, Adamson H, Kohl D, Tiede C, Wälti C, Tomlinson DC, Jeuken LJC. Enzyme - Switch sensors for therapeutic drug monitoring of immunotherapies. Biosens Bioelectron 2023; 237:115488. [PMID: 37419072 PMCID: PMC10427837 DOI: 10.1016/j.bios.2023.115488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 05/19/2023] [Accepted: 06/16/2023] [Indexed: 07/09/2023]
Abstract
Therapeutic monoclonal antibodies (TmAb) have emerged as effective treatments for a number of cancers and autoimmune diseases. However, large interpatient disparities in the pharmacokinetics of TmAb treatment requires close therapeutic drug monitoring (TDM) to optimise dosage for individual patients. Here we demonstrate an approach for achieving rapid, sensitive quantification of two monoclonal antibody therapies using a previously described enzyme switch sensor platform. The enzyme switch sensor consists of a β-lactamase - β-lactamase inhibitor protein (BLA-BLIP) complex with two anti-idiotype binding proteins (Affimer proteins) as recognition elements. The BLA-BLIP sensor was engineered to detect two TmAbs (trastuzumab and ipilimumab) by developing constructs incorporating novel synthetic binding reagents to each of these mAbs. Trastuzumab and ipilimumab were successfully monitored with sub nM sensitivity in up to 1% serum, thus covering the relevant therapeutic range. Despite the modular design, the BLA-BLIP sensor was unsuccessful in detecting two further TmAbs (rituximab and adalimumab), an explanation for which was explored. In conclusion, the BLA-BLIP sensors provide a rapid biosensor for TDM of trastuzumab and ipilimumab with the potential to improve therapy. The sensitivity of this platform alongside its rapid action would be suitable for bedside monitoring in a point-of-care (PoC) setting.
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Affiliation(s)
- Emma Campbell
- School of Biomedical Science, University of Leeds, Leeds, LS2 9JT, United Kingdom; Astbury Centre for Structural Molecular Biology, University of Leeds, LS2 9JT, United Kingdom
| | - Hope Adamson
- School of Biomedical Science, University of Leeds, Leeds, LS2 9JT, United Kingdom; Astbury Centre for Structural Molecular Biology, University of Leeds, LS2 9JT, United Kingdom
| | - Declan Kohl
- School of Biomedical Science, University of Leeds, Leeds, LS2 9JT, United Kingdom; Astbury Centre for Structural Molecular Biology, University of Leeds, LS2 9JT, United Kingdom
| | - Christian Tiede
- Astbury Centre for Structural Molecular Biology, University of Leeds, LS2 9JT, United Kingdom; School of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Christoph Wälti
- School of Electronic and Electrical Engineering, University of Leeds, LS2 9JT, United Kingdom
| | - Darren C Tomlinson
- Astbury Centre for Structural Molecular Biology, University of Leeds, LS2 9JT, United Kingdom; School of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Lars J C Jeuken
- School of Biomedical Science, University of Leeds, Leeds, LS2 9JT, United Kingdom; Astbury Centre for Structural Molecular Biology, University of Leeds, LS2 9JT, United Kingdom; Leiden Institute of Chemistry, Leiden University, PO Box 9502, 2300 RA, Leiden, the Netherlands.
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5
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Müller W, Beales PA, Muniz AR, Jeuken LJC. Unraveling the Phase Behavior, Mechanical Stability, and Protein Reconstitution Properties of Polymer-Lipid Hybrid Vesicles. Biomacromolecules 2023; 24:4156-4169. [PMID: 37539954 PMCID: PMC10498451 DOI: 10.1021/acs.biomac.3c00498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/20/2023] [Indexed: 08/05/2023]
Abstract
Hybrid vesicles consisting of natural phospholipids and synthetic amphiphilic copolymers have shown remarkable material properties and potential for biotechnology, combining the robustness of polymers with the biocompatibility of phospholipid membranes. To predict and optimize the mixing behavior of lipids and copolymers, as well as understand the interaction between the hybrid membrane and macromolecules like membrane proteins, a comprehensive understanding at the molecular level is essential. This can be achieved by a combination of molecular dynamics simulations and experiments. Here, simulations of POPC and PBD22-b-PEO14 hybrid membranes are shown, uncovering different copolymer configurations depending on the polymer-to-lipid ratio. High polymer concentrations created thicker membranes with an extended polymer conformation, while high lipid content led to the collapse of the polymer chain. High concentrations of polymer were further correlated with a decreased area compression modulus and altered lateral pressure profiles, hypothesized to result in the experimentally observed improvement in membrane protein reconstitution and resistance toward destabilization by detergents. Finally, simulations of a WALP peptide embedded in the bilayer showed that only membranes with up to 50% polymer content favored a transmembrane configuration. These simulations correlate with previous and new experimental results and provide a deeper understanding of the properties of lipid-copolymer hybrid membranes.
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Affiliation(s)
- Wagner
A. Müller
- Department
of Chemical Engineering, Universidade Federal
do Rio Grande do Sul, Porto
Alegre 90035-003, Brazil
| | - Paul A. Beales
- School
of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K.
| | - André R. Muniz
- Department
of Chemical Engineering, Universidade Federal
do Rio Grande do Sul, Porto
Alegre 90035-003, Brazil
| | - Lars J. C. Jeuken
- Leiden
Institute of Chemistry, University Leiden, PO Box 9502, 2300RA Leiden, The
Netherlands
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6
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Seneviratne R, Coates G, Xu Z, Cornell CE, Thompson RF, Sadeghpour A, Maskell DP, Jeuken LJC, Rappolt M, Beales PA. High Resolution Membrane Structures within Hybrid Lipid-Polymer Vesicles Revealed by Combining X-Ray Scattering and Electron Microscopy. Small 2023; 19:e2206267. [PMID: 36866488 DOI: 10.1002/smll.202206267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 01/26/2023] [Indexed: 06/02/2023]
Abstract
Hybrid vesicles consisting of phospholipids and block-copolymers are increasingly finding applications in science and technology. Herein, small angle X-ray scattering (SAXS) and cryo-electron tomography (cryo-ET) are used to obtain detailed structural information about hybrid vesicles with different ratios of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and poly(1,2-butadiene-block-ethylene oxide) (PBd22 -PEO14 , Ms = 1800 g mol-1 ). Using single particle analysis (SPA) the authors are able to further interpret the information gained from SAXS and cryo-ET experiments, showing that increasing PBd22 -PEO14 mole fraction increases the membrane thickness from 52 Å for a pure lipid system to 97 Å for pure PBd22 -PEO14 vesicles. Two vesicle populations with different membrane thicknesses in hybrid vesicle samples are found. As these lipids and polymers are reported to homogeneously mix, bistability is inferred between weak and strong interdigitation regimes of PBd22 -PEO14 within the hybrid membranes. It is hypothesized that membranes of intermediate structure are not energetically favorable. Therefore, each vesicle exists in one of these two membrane structures, which are assumed to have comparable free energies. The authors conclude that, by combining biophysical methods, accurate determination of the influence of composition on the structural properties of hybrid membranes is achieved, revealing that two distinct membranes structures can coexist in homogeneously mixed lipid-polymer hybrid vesicles.
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Affiliation(s)
- Rashmi Seneviratne
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Georgina Coates
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Zexi Xu
- School of Food Science and Nutrition, School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Caitlin E Cornell
- Department of Bioengineering, University of California, Berkeley, CA, 94720, USA
| | - Rebecca F Thompson
- School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Amin Sadeghpour
- School of Food Science and Nutrition, University of Leeds, Leeds, LS2 9JT, UK
| | - Daniel P Maskell
- School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Lars J C Jeuken
- Leiden Institute of Chemistry, Leiden University, PC Box 9502, Leiden, 2300 RA, Netherlands
| | - Michael Rappolt
- School of Food Science and Nutrition, University of Leeds, Leeds, LS2 9JT, UK
| | - Paul A Beales
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
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7
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Piper SEH, Casadevall C, Reisner E, Clarke TA, Jeuken LJC, Gates AJ, Butt JN. Photocatalytic Removal of the Greenhouse Gas Nitrous Oxide by Liposomal Microreactors. Angew Chem Int Ed Engl 2022; 61:e202210572. [PMID: 35951464 PMCID: PMC9825952 DOI: 10.1002/anie.202210572] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Indexed: 01/11/2023]
Abstract
Nitrous oxide (N2 O) is a potent greenhouse and ozone-reactive gas for which emissions are growing rapidly due to increasingly intensive agriculture. Synthetic catalysts for N2 O decomposition typically contain precious metals and/or operate at elevated temperatures driving a desire for more sustainable alternatives. Here we demonstrate self-assembly of liposomal microreactors enabling catalytic reduction of N2 O to the climate neutral product N2 . Photoexcitation of graphitic N-doped carbon dots delivers electrons to encapsulated N2 O Reductase enzymes via a lipid-soluble biomolecular wire provided by the MtrCAB protein complex. Within the microreactor, electron transfer from MtrCAB to N2 O Reductase is facilitated by the general redox mediator methyl viologen. The liposomal microreactors use only earth-abundant elements to catalyze N2 O removal in ambient, aqueous conditions.
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Affiliation(s)
- Samuel E. H. Piper
- School of ChemistryUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK
| | - Carla Casadevall
- Yusuf Hamied Department of ChemistryUniversity of CambridgeLensfield RoadCambridgeCB2 1EWUK
| | - Erwin Reisner
- Yusuf Hamied Department of ChemistryUniversity of CambridgeLensfield RoadCambridgeCB2 1EWUK
| | - Thomas A. Clarke
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK
| | - Lars J. C. Jeuken
- Leiden Institute of ChemistryLeiden UniversityPO Box 95022300 RALeidenThe Netherlands
| | - Andrew J. Gates
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK
| | - Julea N. Butt
- School of ChemistryUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK,School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK
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8
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Piper SEH, Casadevall C, Reisner E, Clarke TA, Jeuken LJC, Gates AJ, Butt JN. Photocatalytic Removal of the Greenhouse Gas Nitrous Oxide by Liposomal Microreactors. Angew Chem Weinheim Bergstr Ger 2022; 134:e202210572. [PMID: 38529325 PMCID: PMC10962689 DOI: 10.1002/ange.202210572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Indexed: 11/11/2022]
Abstract
Nitrous oxide (N2O) is a potent greenhouse and ozone-reactive gas for which emissions are growing rapidly due to increasingly intensive agriculture. Synthetic catalysts for N2O decomposition typically contain precious metals and/or operate at elevated temperatures driving a desire for more sustainable alternatives. Here we demonstrate self-assembly of liposomal microreactors enabling catalytic reduction of N2O to the climate neutral product N2. Photoexcitation of graphitic N-doped carbon dots delivers electrons to encapsulated N2O Reductase enzymes via a lipid-soluble biomolecular wire provided by the MtrCAB protein complex. Within the microreactor, electron transfer from MtrCAB to N2O Reductase is facilitated by the general redox mediator methyl viologen. The liposomal microreactors use only earth-abundant elements to catalyze N2O removal in ambient, aqueous conditions.
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Affiliation(s)
- Samuel E. H. Piper
- School of ChemistryUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK
| | - Carla Casadevall
- Yusuf Hamied Department of ChemistryUniversity of CambridgeLensfield RoadCambridgeCB2 1EWUK
| | - Erwin Reisner
- Yusuf Hamied Department of ChemistryUniversity of CambridgeLensfield RoadCambridgeCB2 1EWUK
| | - Thomas A. Clarke
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK
| | - Lars J. C. Jeuken
- Leiden Institute of ChemistryLeiden UniversityPO Box 95022300 RALeidenThe Netherlands
| | - Andrew J. Gates
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK
| | - Julea N. Butt
- School of ChemistryUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK
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9
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Luxton TN, King N, Wälti C, Jeuken LJC, Sandoe JAT. A Systematic Review of the Effect of Therapeutic Drug Monitoring on Patient Health Outcomes during Treatment with Carbapenems. Antibiotics (Basel) 2022; 11:antibiotics11101311. [PMID: 36289971 PMCID: PMC9598625 DOI: 10.3390/antibiotics11101311] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 09/23/2022] [Accepted: 09/26/2022] [Indexed: 11/16/2022] Open
Abstract
Adjusting dosing regimens based on measurements of carbapenem levels may improve carbapenem exposure in patients. This systematic review aims to describe the effect carbapenem therapeutic drug monitoring (TDM) has on health outcomes, including the emergence of antimicrobial resistance (AMR). Four databases were searched for studies that reported health outcomes following adjustment to dosing regimens, according to measurements of carbapenem concentration. Bias in the studies was assessed with risk of bias analysis tools. Study characteristics and outcomes were tabulated and a narrative synthesis was performed. In total, 2 randomised controlled trials (RCTs), 17 non-randomised studies, and 19 clinical case studies were included. Significant variation in TDM practice was seen; consequently, a meta-analysis was unsuitable. Few studies assessed impacts on AMR. No significant improvement on health outcomes and no detrimental effects of carbapenem TDM were observed. Five cohort studies showed significant associations between achieving target concentrations and clinical success, including suppression of resistance. Studies in this review showed no obvious improvement in clinical outcomes when TDM is implemented. Optimisation and standardisation of carbapenem TDM practice are needed to improve intervention success and enable study synthesis. Further suitably powered studies of standardised TDM are required to assess the impact of TMD on clinical outcomes and AMR.
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Affiliation(s)
- Timothy N. Luxton
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
- Correspondence:
| | - Natalie King
- Leeds Institute of Health Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Christoph Wälti
- School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK
| | - Lars J. C. Jeuken
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
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10
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Adamson H, Ajayi MO, Gilroy KE, McPherson MJ, Tomlinson DC, Jeuken LJC. Rapid Quantification of C. difficile Glutamate Dehydrogenase and Toxin B (TcdB) with a NanoBiT Split-Luciferase Assay. Anal Chem 2022; 94:8156-8163. [PMID: 35634999 PMCID: PMC9201815 DOI: 10.1021/acs.analchem.1c05206] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
C. difficile infection (CDI) is a leading healthcare-associated
infection with a high morbidity and mortality and is a financial burden.
No current standalone point-of-care test (POCT) is sufficient for
the identification of true CDI over a disease-free carriage of C. difficile, so one is urgently required to ensure timely,
appropriate treatment. Here, two types of binding proteins, Affimers
and nanobodies, targeting two C. difficile biomarkers,
glutamate dehydrogenase (GDH) and toxin B (TcdB), are combined in
NanoBiT (NanoLuc Binary Technology) split-luciferase assays. The assays
were optimized and their performance controlling parameters were examined.
The 44 fM limit of detection (LoD), 4–5 log range and 1300-fold
signal gain of the TcdB assay in buffer is the best observed for a
NanoBiT assay to date. In the stool sample matrix, the GDH and TcdB
assay sensitivity (LoD = 4.5 and 2 pM, respectively) and time to result
(32 min) are similar to a current, commercial lateral flow POCT, but
the NanoBit assay has no wash steps, detects clinically relevant TcdB
over TcdA, and is quantitative. Development of the assay into a POCT
may drive sensitivity further and offer an urgently needed ultrasensitive
TcdB test for the rapid diagnosis of true CDI. The NanoBiTBiP (NanoBiT
with Binding Proteins) system offers advantages over NanoBiT assays
with antibodies as binding elements in terms of ease of production
and assay performance. We expect this methodology and approach to
be generally applicable to other biomarkers.
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Affiliation(s)
- Hope Adamson
- School of Biomedical Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Modupe O. Ajayi
- School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Kate E. Gilroy
- School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Michael J. McPherson
- School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Darren C. Tomlinson
- School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Lars J. C. Jeuken
- School of Biomedical Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom
- Leiden Institute of Chemistry, Leiden University, PC Box 9502, 2300 RA, Leiden, The Netherlands
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11
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Catania R, Machin J, Rappolt M, Muench SP, Beales PA, Jeuken LJC. Detergent-Free Functionalization of Hybrid Vesicles with Membrane Proteins Using SMALPs. Macromolecules 2022; 55:3415-3422. [PMID: 35571225 PMCID: PMC9097535 DOI: 10.1021/acs.macromol.2c00326] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 04/08/2022] [Indexed: 11/28/2022]
Abstract
![]()
Hybrid
vesicles (HVs) that consist of mixtures of block copolymers
and lipids are robust biomimetics of liposomes, providing a valuable
building block in bionanotechnology, catalysis, and synthetic biology.
However, functionalization of HVs with membrane proteins remains laborious
and expensive, creating a significant current challenge in the field.
Here, using a new approach of extraction with styrene-maleic acid
(SMA), we show that a membrane protein (cytochrome bo3) directly transfers into HVs with an efficiency of 73.9
± 13.5% without the requirement of detergent, long incubation
times, or mechanical disruption. Direct transfer of membrane proteins
using this approach was not possible into liposomes, suggesting that
HVs are more amenable than liposomes to membrane protein incorporation
from a SMA lipid particle system. Finally, we show that this transfer
method is not limited to cytochrome bo3 and can also be performed with complex membrane protein mixtures.
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Affiliation(s)
- Rosa Catania
- Astbury Centre of Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, U.K
| | - Jonathan Machin
- Astbury Centre of Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, U.K
| | - Michael Rappolt
- School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, U.K
| | - Stephen P. Muench
- Astbury Centre of Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, U.K
| | - Paul A. Beales
- Astbury Centre of Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K
- School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K
| | - Lars J. C. Jeuken
- Astbury Centre of Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, U.K
- Leiden Institute of Chemistry, University Leiden, Leiden 2300RA, The Netherlands
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12
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Jeuken LJC. Biodegradation of pollutants by exoelectrogenic bacteria is not always performed extracellularly. Environ Microbiol 2022; 24:1835-1837. [PMID: 35199430 PMCID: PMC9305215 DOI: 10.1111/1462-2920.15942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 02/14/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Lars J C Jeuken
- Leiden Institute of Chemistry, Leiden University, PO Box 9502, 2300RA, Leiden, the Netherlands
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13
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Seneviratne R, Catania R, Rappolt M, Jeuken LJC, Beales PA. Membrane mixing and dynamics in hybrid POPC/poly(1,2-butadiene- block-ethylene oxide) (PBd- b-PEO) lipid/block co-polymer giant vesicles. Soft Matter 2022; 18:1294-1301. [PMID: 35048939 DOI: 10.1039/d1sm01591e] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Lipids and block copolymers can individually self-assemble into vesicles, each with their own particular benefits and limitations. Combining polymers with lipids allows for further optimisation of the vesicle membranes for bionanotechnology applications. Here, POPC lipid is mixed with poly(1,2-butadiene-block-ethylene oxide) of two different molecular weights (PBd22-PEO14, Mr = 1800 g mol-1 and PBd12-PEO11, Mr = 1150 g mol-1) in order to investigate how increasing the polymer fraction affects membrane mixing, hydration and fluidity. Intensity contributions of fluorescently labelled lipid and polymer within mixed GUV membranes confirm membrane homogeneity within the hybrids. General polarisation measurements of Laurdan in GUVs showed little change in membrane hydration as polymer fraction is increased, which suggests good structural compatibility between lipids and polymers that gives rise to well-mixed vesicles. Membrane fluidity in hybrid GUVs was found to decrease non-linearly with increasing polymer fraction. However, the diffusion coefficients for the fluorescent polymer in hybrid membranes did not change significantly with increasing polymer content. While increasing the polymer fraction does reduce the movement of lipids through a polymer-rich matrix, insignificant difference in diffusion coefficients of the polymer suggests that its diffusion is minimally affected by increasing lipid composition in the range studied. These results lay further foundations for the wider development of hybrid vesicles with controlled properties for advanced biotechnologies.
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Affiliation(s)
- Rashmi Seneviratne
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK.
| | - Rosa Catania
- School of Biomedical Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Michael Rappolt
- School of Food Science and Nutrition, University of Leeds, Leeds, LS2 9JT, UK
| | - Lars J C Jeuken
- School of Biomedical Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Paul A Beales
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK.
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14
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Hancock AM, Son M, Nairat M, Wei T, Jeuken LJC, Duffy CDP, Schlau-Cohen GS, Adams PG. Ultrafast energy transfer between lipid-linked chromophores and plant light-harvesting complex II. Phys Chem Chem Phys 2021; 23:19511-19524. [PMID: 34524278 PMCID: PMC8442836 DOI: 10.1039/d1cp01628h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Light-Harvesting Complex II (LHCII) is a membrane protein found in plant chloroplasts that has the crucial role of absorbing solar energy and subsequently performing excitation energy transfer to the reaction centre subunits of Photosystem II. LHCII provides strong absorption of blue and red light, however, it has minimal absorption in the green spectral region where solar irradiance is maximal. In a recent proof-of-principle study, we enhanced the absorption in this spectral range by developing a biohybrid system where LHCII proteins together with lipid-linked Texas Red (TR) chromophores were assembled into lipid membrane vesicles. The utility of these systems was limited by significant LHCII quenching due to protein-protein interactions and heterogeneous lipid structures. Here, we organise TR and LHCII into a lipid nanodisc, which provides a homogeneous, well-controlled platform to study the interactions between TR molecules and single LHCII complexes. Fluorescence spectroscopy determined that TR-to-LHCII energy transfer has an efficiency of at least 60%, resulting in a 262% enhancement of LHCII fluorescence in the 525-625 nm range, two-fold greater than in the previous system. Ultrafast transient absorption spectroscopy revealed two time constants of 3.7 and 128 ps for TR-to-LHCII energy transfer. Structural modelling and theoretical calculations indicate that these timescales correspond to TR-lipids that are loosely- or tightly-associated with the protein, respectively, with estimated TR-to-LHCII separations of ∼3.5 nm and ∼1 nm. Overall, we demonstrate that a nanodisc-based biohybrid system provides an idealised platform to explore the photophysical interactions between extrinsic chromophores and membrane proteins with potential applications in understanding more complex natural or artificial photosynthetic systems.
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Affiliation(s)
- Ashley M Hancock
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK. .,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Minjung Son
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA.
| | - Muath Nairat
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA.
| | - Tiejun Wei
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Lars J C Jeuken
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK.,Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.,Leiden Institute of Chemistry, Leiden University, 2300 RA Leiden, The Netherlands
| | - Christopher D P Duffy
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Gabriela S Schlau-Cohen
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA.
| | - Peter G Adams
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK. .,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
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15
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Piper SEH, Edwards MJ, van Wonderen JH, Casadevall C, Martel A, Jeuken LJC, Reisner E, Clarke TA, Butt JN. Bespoke Biomolecular Wires for Transmembrane Electron Transfer: Spontaneous Assembly of a Functionalized Multiheme Electron Conduit. Front Microbiol 2021; 12:714508. [PMID: 34484155 PMCID: PMC8415449 DOI: 10.3389/fmicb.2021.714508] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 07/12/2021] [Indexed: 11/13/2022] Open
Abstract
Shewanella oneidensis exchanges electrons between cellular metabolism and external redox partners in a process that attracts much attention for production of green electricity (microbial fuel cells) and chemicals (microbial electrosynthesis). A critical component of this pathway is the outer membrane spanning MTR complex, a biomolecular wire formed of the MtrA, MtrB, and MtrC proteins. MtrA and MtrC are decaheme cytochromes that form a chain of close-packed hemes to define an electron transfer pathway of 185 Å. MtrA is wrapped inside MtrB for solubility across the outer membrane lipid bilayer; MtrC sits outside the cell for electron exchange with external redox partners. Here, we demonstrate tight and spontaneous in vitro association of MtrAB with separately purified MtrC. The resulting complex is comparable with the MTR complex naturally assembled by Shewanella in terms of both its structure and rates of electron transfer across a lipid bilayer. Our findings reveal the potential for building bespoke electron conduits where MtrAB combines with chemically modified MtrC, in this case, labeled with a Ru-dye that enables light-triggered electron injection into the MtrC heme chain.
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Affiliation(s)
- Samuel E H Piper
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Marcus J Edwards
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Jessica H van Wonderen
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Carla Casadevall
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | | | - Lars J C Jeuken
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Erwin Reisner
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Thomas A Clarke
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Julea N Butt
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
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16
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Wilding S, Kettu V, Thompson W, Howard P, Jeuken LJC, Pownall M, Conner M, Sandoe JAT. Development and randomized controlled trial of an animated film aimed at reducing behaviours for acquiring antibiotics. JAC Antimicrob Resist 2021; 3:dlab083. [PMID: 34223142 PMCID: PMC8251327 DOI: 10.1093/jacamr/dlab083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 05/17/2021] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Antimicrobial resistance (AMR) is a global health crisis but reducing antibiotic use can help. Some antibiotic use is driven by patient demand. OBJECTIVES To develop an intervention to discourage antibiotic-seeking behaviour in adults. METHODS Literature reviewed to identify behaviours for acquiring antibiotics among adults in the community. Behaviour change wheel approach was used to select the target behaviour and behaviour change techniques. An intervention in the form of a short animated film was developed and its potential impact evaluated in a randomized, controlled, online questionnaire study. RESULTS Asking a general medical/dental practitioner for antibiotics was identified as the target behaviour. A short stop-motion animated film was chosen to deliver several behaviour-change techniques. Education and persuasion were delivered around information about the normal microbial flora, its importance for health, the negative effect of antibiotics, and about AMR. 417 UK-based individuals completed the questionnaire; median age 34.5 years, 71% female, 91% white ethnicity. 3.8% of participants viewing the test film intended to ask for antibiotics compared with 7.9% viewing the control film. Test film viewers had significantly higher knowledge scores. At 6 week follow up, knowledge scores remained significantly different, while most attitude and intention scores were not different. CONCLUSIONS Some patients continue to ask for antibiotics. The film increased knowledge and reduced intentions to ask for antibiotics. At 6 weeks, knowledge gains remained but intentions not to ask for antibiotics had waned. Evaluation in the clinical environment, probably at the point of care, is needed to see if antibiotic prescribing can be impacted.
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Affiliation(s)
- Sarah Wilding
- School of Psychology, University of
Leeds, Leeds, UK
| | | | - Wendy Thompson
- Division of Dentistry, University of
Manchester, Manchester, UK
| | - Philip Howard
- School of Healthcare, University of
Leeds, Leeds, UK
- Leeds Teaching Hospitals NHS Trust,
Leeds, UK
| | - Lars J C Jeuken
- School of Biomedical Sciences, University of
Leeds, Leeds, UK
| | | | - Mark Conner
- School of Psychology, University of
Leeds, Leeds, UK
| | - Jonathan A T Sandoe
- Leeds Teaching Hospitals NHS Trust,
Leeds, UK
- Leeds Institute of Medical Research, School of
Medicine, University of Leeds, Leeds, UK
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17
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Abstract
Biological signaling pathways are underpinned by protein switches that sense and respond to molecular inputs. Inspired by nature, engineered protein switches have been designed to directly transduce analyte binding into a quantitative signal in a simple, wash-free, homogeneous assay format. As such, they offer great potential to underpin point-of-need diagnostics that are needed across broad sectors to improve access, costs, and speed compared to laboratory assays. Despite this, protein switch assays are not yet in routine diagnostic use, and a number of barriers to uptake must be overcome to realize this potential. Here, we review the opportunities and challenges in engineering protein switches for rapid diagnostic tests. We evaluate how their design, comprising a recognition element, reporter, and switching mechanism, relates to performance and identify areas for improvement to guide further optimization. Recent modular switches that enable new analytes to be targeted without redesign are crucial to ensure robust and efficient development processes. The importance of translational steps toward practical implementation, including integration into a user-friendly device and thorough assay validation, is also discussed.
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Affiliation(s)
- Hope Adamson
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Lars J. C. Jeuken
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
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18
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Seneviratne R, Jeuken LJC, Rappolt M, Beales PA. Hybrid Vesicle Stability under Sterilisation and Preservation Processes Used in the Manufacture of Medicinal Formulations. Polymers (Basel) 2020; 12:polym12040914. [PMID: 32326448 PMCID: PMC7240416 DOI: 10.3390/polym12040914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 03/30/2020] [Accepted: 04/09/2020] [Indexed: 11/16/2022] Open
Abstract
Sterilisation and preservation of vesicle formulations are important considerations for their viable manufacture for industry applications, particular those intended for medicinal use. Here, we undertake an initial investigation of the stability of hybrid lipid-block copolymer vesicles to common sterilisation and preservation processes, with particular interest in how the block copolymer component might tune vesicle stability. We investigate two sizes of polybutadiene-block-poly(ethylene oxide) polymers (PBd12-PEO11 and PBd22-PEO14) mixed with the phospholipid 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) considering the encapsulation stability of a fluorescent cargo and the colloidal stability of vesicle size distributions. We find that autoclaving and lyophilisation cause complete loss of encapsulation stability under the conditions studied here. Filtering through 200 nm pores appears to be viable for sterilisation for all vesicle compositions with comparatively low release of encapsulated cargo, even for vesicle size distributions which extend beyond the 200 nm filter pore size. Freeze-thaw of vesicles also shows promise for the preservation of hybrid vesicles with high block copolymer content. We discuss the process stability of hybrid vesicles in terms of the complex mechanical interplay between bending resistance, stretching elasticity and lysis strain of these membranes and propose strategies for future work to further enhance the process stability of these vesicle formulations.
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Affiliation(s)
- Rashmi Seneviratne
- School of Chemistry, Astbury Centre for Structural Molecular Biology and Bragg Centre for Materials Research, University of Leeds, Leeds LS2 9JT, UK;
| | - Lars J. C. Jeuken
- School of Biomedical Sciences, Astbury Centre for Structural Molecular Biology and Bragg Centre for Materials Research, University of Leeds, Leeds LS2 9JT, UK;
| | - Michael Rappolt
- School of Food Science and Nutrition and Bragg Centre for Materials Research, University of Leeds, Leeds LS2 9JT, UK;
| | - Paul A. Beales
- School of Chemistry, Astbury Centre for Structural Molecular Biology and Bragg Centre for Materials Research, University of Leeds, Leeds LS2 9JT, UK;
- Correspondence:
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19
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Wroblewska-Wolna AM, Harvie AJ, Rowe SF, Critchley K, Butt JN, Jeuken LJC. Quantum dot interactions with and toxicity to Shewanella oneidensis MR-1. Nanotechnology 2020; 31:134005. [PMID: 31810073 DOI: 10.1088/1361-6528/ab5f78] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Combining abiotic photosensitisers such as quantum dots (QDs) with non-photosynthetic bacteria presents an intriguing concept into the design of artificial photosynthetic organisms and solar-driven fuel production. Shewanella oneidensis MR-1 (MR-1) is a versatile bacterium concerning respiration, metabolism and biocatalysis, and is a promising organism for artificial photosynthesis as the bacterium's synthetic and catalytic ability provides a potential system for bacterial biohydrogen production. MR-1's hydrogenases are present in the periplasmatic space. It follows that for photoenergised electrons to reach these enzymes, QDs will need to be able to enter the periplasm, or electrons need to enter the periplasm via the Mtr pathway that is responsible for MR-1's extracellular electron transfer ability. As a step towards this goal, various QDs were tested for their photo-reducing potential, nanotoxicology and further for their interaction with MR-1. CdTe/CdS/TGA, CdTe/CdS/Cysteamine, a commercial, negatively charged CdTe and CuInS2/ZnS/PMAL QDs were examined. The photoreduction potential of the QDs was confirmed by measuring their ability to photoreduce methyl viologen with different sacrificial electron donors. The commercial CdTe and CuInS2/ZnS/PMAL QDs showed no toxicity towards MR-1 as evaluated by a colony-forming units method and a fluorescence viability assay. Only the commercial negatively charged CdTe QDs showed good interaction with MR-1. With transmission electron microscopy, QDs were observed both in the cytoplasm and periplasm. These results inform on the possibilities and bottlenecks when developing bionanotechnological systems for the photosynthetic production of biohydrogen by MR-1.
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20
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Nakatani Y, Shimaki Y, Dutta D, Muench SP, Ireton K, Cook GM, Jeuken LJC. Unprecedented Properties of Phenothiazines Unraveled by a NDH-2 Bioelectrochemical Assay Platform. J Am Chem Soc 2020; 142:1311-1320. [PMID: 31880924 DOI: 10.1021/jacs.9b10254] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Type II NADH:quinone oxidoreductase (NDH-2) plays a crucial role in the respiratory chains of many organisms. Its absence in mammalian cells makes NDH-2 an attractive new target for developing antimicrobials and antiprotozoal agents. We established a novel bioelectrochemical platform to characterize the catalytic behavior of NDH-2 from Caldalkalibacillus thermarum and Listeria monocytogenes strain EGD-e while bound to native-like lipid membranes. Catalysis of both NADH oxidation and lipophilic quinone reduction by membrane-bound NDH-2 followed the Michaelis-Menten model; however, the maximum turnover was only achieved when a high concentration of quinone (>3 mM) was present in the membrane, suggesting that quinone availability regulates NADH-coupled respiration activity. The quinone analogue 2-heptyl-4-hydroxyquinoline-N-oxide inhibited C. thermarum NDH-2 activity, and its potency is higher in a membrane environment compared to assays performed with water-soluble quinone analogues, demonstrating the importance of testing compounds under physiologically relevant conditions. Furthermore, when phenothiazines, one of the most commonly identified NDH-2 inhibitors, were tested, they did not inhibit membrane-bound NDH-2. Instead, our assay platform unexpectedly suggests a novel mode of phenothiazine action where chlorpromazine, a promising antitubercular agent and key medicine used to treat psychotic disorders, is able to disrupt pH gradients across bacterial membranes.
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Affiliation(s)
- Yoshio Nakatani
- Department of Microbiology and Immunology , University of Otago , Dunedin 9054 , New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery , The University of Auckland , Private Bag 92019, Auckland 1042 , New Zealand
| | - Yosuke Shimaki
- Department of Microbiology and Immunology , University of Otago , Dunedin 9054 , New Zealand
| | - Debajyoti Dutta
- School of Biomedical Sciences and the Astbury Centre for Structural Molecular Biology , University of Leeds , Leeds LS2 9JT , United Kingdom
| | - Stephen P Muench
- School of Biomedical Sciences and the Astbury Centre for Structural Molecular Biology , University of Leeds , Leeds LS2 9JT , United Kingdom
| | - Keith Ireton
- Department of Microbiology and Immunology , University of Otago , Dunedin 9054 , New Zealand
| | - Gregory M Cook
- Department of Microbiology and Immunology , University of Otago , Dunedin 9054 , New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery , The University of Auckland , Private Bag 92019, Auckland 1042 , New Zealand
| | - Lars J C Jeuken
- School of Biomedical Sciences and the Astbury Centre for Structural Molecular Biology , University of Leeds , Leeds LS2 9JT , United Kingdom
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21
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Adamson H, Ajayi MO, Campbell E, Brachi E, Tiede C, Tang AA, Adams TL, Ford R, Davidson A, Johnson M, McPherson MJ, Tomlinson DC, Jeuken LJC. Affimer-Enzyme-Inhibitor Switch Sensor for Rapid Wash-free Assays of Multimeric Proteins. ACS Sens 2019; 4:3014-3022. [PMID: 31578863 DOI: 10.1021/acssensors.9b01574] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Robust technology is required to underpin rapid point-of-care and in-field diagnostics to improve timely decision making across broad sectors. An attractive strategy combines target recognition and signal generating elements into an "active" enzyme-switch that directly transduces target-binding into a signal. However, approaches that are broadly applicable to diverse targets remain elusive. Here, an enzyme-inhibitor switch sensor was developed by insertion of non-immunoglobulin Affimer binding proteins, between TEM1-β-lactamase and its inhibitor protein, such that target binding disrupts the enzyme-inhibitor complex. Design principles for a successful switch architecture are illustrated by the rapid (min), simple (wash-free), and sensitive (pM) quantification of multimeric target analytes in biological samples (serum, plasma, leaf extracts), across three application areas. A therapeutic antibody (Herceptin), protein biomarker (human C-reactive protein), and plant virus (cow pea mosaic virus) were targeted, demonstrating assays for therapeutic drug monitoring, health diagnostics, and plant pathogen detection, respectively. Batch-to-batch reproducibility, shelf-life stability, and consistency with validated enzyme-linked immunosorbent assay analysis confirm that the principle of an Affimer-enzyme-inhibitor switch provides a platform for point-of-care and in-field diagnostics.
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Affiliation(s)
| | | | | | | | | | | | | | - Robert Ford
- Avacta Life Sciences Limited, Unit 20, Ash Way, Thorp Arch Estate, Wetherby LS23 7FA, U.K
| | - Alex Davidson
- Avacta Life Sciences Limited, Unit 20, Ash Way, Thorp Arch Estate, Wetherby LS23 7FA, U.K
| | - Matt Johnson
- Avacta Life Sciences Limited, Unit 20, Ash Way, Thorp Arch Estate, Wetherby LS23 7FA, U.K
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22
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Hancock AM, Meredith SA, Connell SD, Jeuken LJC, Adams PG. Proteoliposomes as energy transferring nanomaterials: enhancing the spectral range of light-harvesting proteins using lipid-linked chromophores. Nanoscale 2019; 11:16284-16292. [PMID: 31465048 DOI: 10.1039/c9nr04653d] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Bio-hybrid nanomaterials have great potential for combining the most desirable aspects of biomolecules and the contemporary concepts of nanotechnology to create highly efficient light-harvesting materials. Light-harvesting proteins are optimized to absorb and transfer solar energy with remarkable efficiency but have a spectral range that is limited by their natural pigment complement. Herein, we present the development of model membranes ("proteoliposomes") in which the absorption range of the membrane protein Light-Harvesting Complex II (LHCII) is effectively enhanced by the addition of lipid-tethered Texas Red (TR) chromophores. Energy transfer from TR to LHCII is observed with up to 94% efficiency and increased LHCII fluorescence of up to three-fold when excited in the region of lowest natural absorption. The new self-assembly procedure offers the modularity to control the concentrations incorporated of TR and LHCII, allowing energy transfer and fluorescence to be tuned. Fluorescence Lifetime Imaging Microscopy provides single-proteoliposome-level quantification of energy transfer efficiency and confirms that functionality is retained on surfaces. Designer proteoliposomes could act as a controllable light-harvesting nanomaterial and are a promising step in the development of bio-hybrid light-harvesting systems.
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Affiliation(s)
- Ashley M Hancock
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK. and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Sophie A Meredith
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK. and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Simon D Connell
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK. and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Lars J C Jeuken
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK and School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Peter G Adams
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK. and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
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23
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Badiani V, Bajada M, Beller M, Bocarsly AB, Bonnet S, Bozal-Ginesta C, Brueggeller P, Butt JN, Cassiola F, Grätzel M, Hammarström L, Hatzell MC, Jeuken LJC, König B, Kuehnel MF, Lawrence J, Lee CY, Maneiro M, Minteer SD, Moore EE, Piper SEH, Plumeré N, Reek JNH, Reisner E, Roy S, Shears J, Shylin SI, Soo HS, Wagner A, Wielend D, Zhang J, Zwijnenburg M. Biological approaches to artificial photosynthesis: general discussion. Faraday Discuss 2019; 215:66-83. [PMID: 31231740 DOI: 10.1039/c9fd90026h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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24
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Mazurenko I, Hatzakis NS, Jeuken LJC. Single Liposome Measurements for the Study of Proton-Pumping Membrane Enzymes Using Electrochemistry and Fluorescent Microscopy. J Vis Exp 2019. [PMID: 30855567 DOI: 10.3791/58896] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Proton-pumping enzymes of electron transfer chains couple redox reactions to proton translocation across the membrane, creating a proton-motive force used for ATP production. The amphiphilic nature of membrane proteins requires particular attention to their handling, and reconstitution into the natural lipid environment is indispensable when studying membrane transport processes like proton translocation. Here, we detail a method that has been used for the investigation of the proton-pumping mechanism of membrane redox enzymes, taking cytochrome bo3 from Escherichia coli as an example. A combination of electrochemistry and fluorescence microscopy is used to control the redox state of the quinone pool and monitor pH changes in the lumen. Due to the spatial resolution of fluorescent microscopy, hundreds of liposomes can be measured simultaneously while the enzyme content can be scaled down to a single enzyme or transporter per liposome. The respective single enzyme analysis can reveal patterns in the enzyme functional dynamics that might be otherwise hidden by the behavior of the whole population. We include a description of a script for automated image analysis.
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Affiliation(s)
- Ievgen Mazurenko
- School of Biomedical Sciences & the Astbury Centre for Structural Molecular Biology, University of Leeds
| | - Nikos S Hatzakis
- Department of Chemistry and Nano-Science Center, University of Copenhagen
| | - Lars J C Jeuken
- School of Biomedical Sciences & the Astbury Centre for Structural Molecular Biology, University of Leeds;
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25
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Stikane A, Hwang ET, Ainsworth E, Piper SEH, Critchley K, Butt JN, Reisner E, Jeuken LJC. Towards compartmentalized photocatalysis: multihaem proteins as transmembrane molecular electron conduits. Faraday Discuss 2019; 215:26-38. [DOI: 10.1039/c8fd00163d] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We show a proof-of-concept for using MtrCAB as a lipid membrane-spanning building block for compartmentalised photocatalysis that mimics photosynthesis.
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Affiliation(s)
- Anna Stikane
- School of Biomedical Sciences
- University of Leeds
- Leeds
- UK
- The Astbury Centre for Structural Molecular Biology
| | - Ee Taek Hwang
- School of Biomedical Sciences
- University of Leeds
- Leeds
- UK
- The Astbury Centre for Structural Molecular Biology
| | - Emma V. Ainsworth
- Centre for Molecular and Structural Biochemistry
- School of Chemistry and School of Biological Sciences
- University of East Anglia
- Norwich
- UK
| | - Samuel E. H. Piper
- Centre for Molecular and Structural Biochemistry
- School of Chemistry and School of Biological Sciences
- University of East Anglia
- Norwich
- UK
| | - Kevin Critchley
- The Astbury Centre for Structural Molecular Biology
- University of Leeds
- Leeds
- UK
- School of Physics and Astronomy
| | - Julea N. Butt
- Centre for Molecular and Structural Biochemistry
- School of Chemistry and School of Biological Sciences
- University of East Anglia
- Norwich
- UK
| | - Erwin Reisner
- Department of Chemistry
- University of Cambridge
- Cambridge
- UK
| | - Lars J. C. Jeuken
- School of Biomedical Sciences
- University of Leeds
- Leeds
- UK
- The Astbury Centre for Structural Molecular Biology
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26
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Teare P, Smith CF, Adams SJ, Anbu S, Ciani B, Jeuken LJC, Peacock AFA. pH dependent binding in de novo hetero bimetallic coiled coils. Dalton Trans 2018; 47:10784-10790. [PMID: 30022210 DOI: 10.1039/c8dt01568f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein the first example of a bimetallic coiled coil featuring a lanthanide binding site is reported, opening opportunities to exploit the attractive NMR and photophysical properties of the lanthanides in multi metallo protein design. In our efforts to fully characterise the system we identified for the first time that lanthanide binding to such sites is pH dependent, with optimal binding at neutral pH, and that the double AsnAsp site is more versatile in this regard than the single Asp site. Our second site featured the structural HgCys3 site, the chemistry of which was essentially unaltered by the presence of the lanthanide site. In fact, both metal binding sites within the hetero bimetallic coiled coil displayed the same properties as their mononuclear single binding site controls, and operated independently of each other. Finally, pH can be used as an external trigger to control the binding of Hg(ii) and Tb(iii) to the two distinct sites within this coiled coil, and offers the opportunity to "activate" metal binding sites within complex multi metallo and multi-functional designs.
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Affiliation(s)
- Paul Teare
- School of Chemistry, University of Birmingham, Edgbaston, B15 2TT, UK.
| | - Caitlin F Smith
- School of Chemistry, University of Birmingham, Edgbaston, B15 2TT, UK.
| | - Samuel J Adams
- School of Chemistry, University of Birmingham, Edgbaston, B15 2TT, UK.
| | - Sellamuthu Anbu
- School of Chemistry, University of Birmingham, Edgbaston, B15 2TT, UK.
| | - Barbara Ciani
- Centre for Membrane Interactions and Dynamics, and Krebs Institute, Department of Chemistry, University of Sheffield, Sheffield, S3 7HF, UK
| | - Lars J C Jeuken
- School of Biomedical Sciences and the Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Anna F A Peacock
- School of Chemistry, University of Birmingham, Edgbaston, B15 2TT, UK.
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27
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Bawazer LA, Ihli J, Levenstein MA, Jeuken LJC, Meldrum FC, McMillan DGG. Enzymatically-controlled biomimetic synthesis of titania/protein hybrid thin films. J Mater Chem B 2018; 6:3979-3988. [PMID: 32254326 DOI: 10.1039/c8tb00381e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Although it is widely recognised that enzymes play a significant role in sculpting complex silica skeletons in marine sponges, the potential for exploiting enzymes in materials synthesis has not yet been fully harnessed. In this work we show that the digestive enzyme papain can self-assemble into monolayers on oxide surfaces, where they then drive the formation of crystalline titanium dioxide nanoparticles. This dual functionality of thin film formation and mineralization promotion has the potential to enable the construction of hierarchical inorganic/organic structures in the form of continuous amorphous titania/protein films which can be refined to 93% anatase post annealing. Additional control over the film thickness is afforded by layer-by-layer processing using a simple dip-coating approach. Papain's TiO2-mineralizing activity displays complex kinetics that deviates from the native Michaelis-Menten kinetic activity, yet deactivation studies demonstrate that this activity relies upon residues that are essential for catalytic site function. These parameters provide unique insight into enzymatic biomineralization, allowing a flexible route to achieving bioengineered titania heterostructures, and potentially providing a green-chemistry solution to photovoltaic cell development.
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Affiliation(s)
- L A Bawazer
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
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28
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Lee CY, Reuillard B, Sokol KP, Laftsoglou T, Lockwood CWJ, Rowe SF, Hwang ET, Fontecilla-Camps JC, Jeuken LJC, Butt JN, Reisner E. A decahaem cytochrome as an electron conduit in protein-enzyme redox processes. Chem Commun (Camb) 2018; 52:7390-3. [PMID: 27193068 DOI: 10.1039/c6cc02721k] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The decahaem cytochrome MtrC from Shewanella oneidensis MR-1 was employed as a protein electron conduit between a porous indium tin oxide electrode and redox enzymes. Using a hydrogenase and a fumarate reductase, MtrC was shown as a suitable and efficient diode to shuttle electrons to and from the electrode with the MtrC redox activity regulating the direction of the enzymatic reactions.
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Affiliation(s)
- Chong-Yong Lee
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
| | - Bertrand Reuillard
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
| | - Katarzyna P Sokol
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
| | - Theodoros Laftsoglou
- School of Biomedical Sciences and the Astbury Centre, University of Leeds, Leeds, LS2 9JT, UK.
| | - Colin W J Lockwood
- School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK.
| | - Sam F Rowe
- School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK.
| | - Ee Taek Hwang
- School of Biomedical Sciences and the Astbury Centre, University of Leeds, Leeds, LS2 9JT, UK.
| | - Juan C Fontecilla-Camps
- Metalloproteins Unit, Institut de Biologie Structurale, CEA, CNRS, Université Grenoble Alpes, 38044 Grenoble, France
| | - Lars J C Jeuken
- School of Biomedical Sciences and the Astbury Centre, University of Leeds, Leeds, LS2 9JT, UK.
| | - Julea N Butt
- School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK.
| | - Erwin Reisner
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
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29
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Rowe SF, Le Gall G, Ainsworth EV, Davies JA, Lockwood CWJ, Shi L, Elliston A, Roberts IN, Waldron KW, Richardson DJ, Clarke TA, Jeuken LJC, Reisner E, Butt JN. Light-Driven H2 Evolution and C═C or C═O Bond Hydrogenation by Shewanella oneidensis: A Versatile Strategy for Photocatalysis by Nonphotosynthetic Microorganisms. ACS Catal 2017. [DOI: 10.1021/acscatal.7b02736] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sam F. Rowe
- School
of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K
| | - Gwénaëlle Le Gall
- Quadram
Institute for Bioscience, Norwich Research Park, Norwich NR4 7UA, U.K
| | - Emma V. Ainsworth
- School
of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K
| | - Jonathan A. Davies
- School
of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K
| | - Colin W. J. Lockwood
- School
of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K
| | - Liang Shi
- Department
of Biological Sciences and Technology, China University of Geoscience in Wuhan, Wuhan 430074, People’s Republic of China
| | - Adam Elliston
- Quadram
Institute for Bioscience, Norwich Research Park, Norwich NR4 7UA, U.K
| | - Ian N. Roberts
- Quadram
Institute for Bioscience, Norwich Research Park, Norwich NR4 7UA, U.K
| | - Keith W. Waldron
- Quadram
Institute for Bioscience, Norwich Research Park, Norwich NR4 7UA, U.K
| | - David J. Richardson
- School
of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K
| | - Thomas A. Clarke
- School
of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K
| | - Lars J. C. Jeuken
- School
of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, U.K
| | - Erwin Reisner
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
| | - Julea N. Butt
- School
of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K
- School
of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K
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30
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Hwang ET, Orchard KL, Hojo D, Beton J, Lockwood CWJ, Adschiri T, Butt JN, Reisner E, Jeuken LJC. Exploring Step-by-Step Assembly of Nanoparticle:Cytochrome Biohybrid Photoanodes. ChemElectroChem 2017; 4:1959-1968. [PMID: 28920010 PMCID: PMC5573906 DOI: 10.1002/celc.201700030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Indexed: 11/07/2022]
Abstract
Coupling light-harvesting semiconducting nanoparticles (NPs) with redox enzymes has been shown to create artificial photosynthetic systems that hold promise for the synthesis of solar fuels. High quantum yields require efficient electron transfer from the nanoparticle to the redox protein, a property that can be difficult to control. Here, we have compared binding and electron transfer between dye-sensitized TiO2 nanocrystals or CdS quantum dots and two decaheme cytochromes on photoanodes. The effect of NP surface chemistry was assessed by preparing NPs capped with amine or carboxylic acid functionalities. For the TiO2 nanocrystals, binding to the cytochromes was optimal when capped with a carboxylic acid ligand, whereas for the CdS QDs, better adhesion was observed for amine capped ligand shells. When using TiO2 nanocrystals, dye-sensitized with a phosphonated bipyridine Ru(II) dye, photocurrents are observed that are dependent on the redox state of the decaheme, confirming that electrons are transferred from the TiO2 nanocrystals to the surface via the decaheme conduit. In contrast, when CdS NPs are used, photocurrents are not dependent on the redox state of the decaheme, consistent with a model in which electron transfer from CdS to the photoanode bypasses the decaheme protein. These results illustrate that although the organic shell of NPs nanoparticles crucially affects coupling with proteinaceous material, the coupling can be difficult to predict or engineer.
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Affiliation(s)
- Ee Taek Hwang
- School of Biomedical Sciences, and The Astbury Centre for Structural Molecular BiologyUniversity of LeedsLeedsLS2 9JTU.K
| | - Katherine L. Orchard
- Department of ChemistryUniversity of CambridgeLensfield RoadCambridgeCB2 1EWU.K.
- Advanced Institute for Materials ResearchTohoku University2-1-1 Katahira Aoba-ku SendaiMiyagi980-8577Japan
| | - Daisuke Hojo
- Advanced Institute for Materials ResearchTohoku University2-1-1 Katahira Aoba-ku SendaiMiyagi980-8577Japan
| | - Joseph Beton
- School of Biomedical Sciences, and The Astbury Centre for Structural Molecular BiologyUniversity of LeedsLeedsLS2 9JTU.K
| | - Colin W. J. Lockwood
- Centre for Molecular and Structural BiochemistrySchool of Chemistry, and School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUnited Kingdom
| | - Tadafumi Adschiri
- Advanced Institute for Materials ResearchTohoku University2-1-1 Katahira Aoba-ku SendaiMiyagi980-8577Japan
| | - Julea N. Butt
- Centre for Molecular and Structural BiochemistrySchool of Chemistry, and School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUnited Kingdom
| | - Erwin Reisner
- Department of ChemistryUniversity of CambridgeLensfield RoadCambridgeCB2 1EWU.K.
| | - Lars J. C. Jeuken
- School of Biomedical Sciences, and The Astbury Centre for Structural Molecular BiologyUniversity of LeedsLeedsLS2 9JTU.K
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31
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Li M, Khan S, Rong H, Tuma R, Hatzakis NS, Jeuken LJC. Effects of membrane curvature and pH on proton pumping activity of single cytochrome bo 3 enzymes. Biochim Biophys Acta Bioenerg 2017. [PMID: 28634030 DOI: 10.1016/j.bbabio.2017.06.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The molecular mechanism of proton pumping by heme-copper oxidases (HCO) has intrigued the scientific community since it was first proposed. We have recently reported a novel technology that enables the continuous characterisation of proton transport activity of a HCO and ubiquinol oxidase from Escherichia coli, cytochrome bo3, for hundreds of seconds on the single enzyme level (Li et al. J Am Chem Soc 137 (2015) 16055-16063). Here, we have extended these studies by additional experiments and analyses of the proton transfer rate as a function of proteoliposome size and pH at the N- and P-side of single HCOs. Proton transport activity of cytochrome bo3 was found to decrease with increased curvature of the membrane. Furthermore, proton uptake at the N-side (proton entrance) was insensitive to pH between pH6.4-8.4, while proton release at the P-side had an optimum pH of ~7.4, suggesting that the pH optimum is related to proton release from the proton exit site. Our previous single-enzyme experiments identified rare, long-lived conformation states of cytochrome bo3 where protons leak back under turn-over conditions. Here, we analyzed and found that ~23% of cytochrome bo3 proteoliposomes show ΔpH half-lives below 50s after stopping turnover, while only ~5% of the proteoliposomes containing a non-pumping mutant, E286C cytochrome bo3 exhibit such fast decays. These single-enzyme results confirm our model in which HCO exhibit heterogeneous pumping rates and can adopt rare leak states in which protons are able to rapidly flow back.
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Affiliation(s)
- Mengqiu Li
- School of Biomedical Sciences, University of Leeds, LS2 9JT Leeds, UK
| | - Sanobar Khan
- School of Chemistry, University of Leeds, LS2 9JT Leeds, UK
| | - Honglin Rong
- School of Biomedical Sciences, University of Leeds, LS2 9JT Leeds, UK
| | - Roman Tuma
- School of Molecular and Cellular Biology, University of Leeds, LS2 9JT Leeds, UK
| | - Nikos S Hatzakis
- Nano-Science Center, Department of Chemistry, University of Copenhagen, Copenhagen 2100, Denmark.
| | - Lars J C Jeuken
- School of Biomedical Sciences, University of Leeds, LS2 9JT Leeds, UK.
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32
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Abstract
For more than three decades, the field of bioelectrochemistry has provided novel insights into the catalytic mechanisms of enzymes, the principles that govern biological electron transfer, and has elucidated the basic principles for bioelectrocatalytic systems. Progress in biochemistry, bionanotechnology, and our ever increasing ability to control the chemistry and structure of electrode surfaces has enabled the study of ever more complex systems with bioelectrochemistry. This feature article highlights developments over the last decade, where supramolecular approaches have been employed to develop electrode assemblies that increase enzyme loading on the electrode or create more biocompatible environments for membrane enzymes. Two approaches are particularly highlighted: the use of layer-by-layer assembly, and the modification of electrodes with planar lipid membranes.
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Affiliation(s)
- Theodoros Laftsoglou
- School of Biomedical Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, LS2 9JT, Leeds, UK.
| | - Lars J C Jeuken
- School of Biomedical Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, LS2 9JT, Leeds, UK.
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33
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Reuillard B, Ly KH, Hildebrandt P, Jeuken LJC, Butt JN, Reisner E. High Performance Reduction of H 2O 2 with an Electron Transport Decaheme Cytochrome on a Porous ITO Electrode. J Am Chem Soc 2017; 139:3324-3327. [PMID: 28221032 PMCID: PMC5411108 DOI: 10.1021/jacs.6b12437] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Indexed: 11/28/2022]
Abstract
The decaheme cytochrome MtrC from Shewanella oneidensis MR-1 immobilized on an ITO electrode displays unprecedented H2O2 reduction activity. Although MtrC showed lower peroxidase activity in solution compared to horseradish peroxidase, the ten heme cofactors enable excellent electronic communication and a superior activity on the electrode surface. A hierarchical ITO electrode enabled optimal immobilization of MtrC and a high current density of 1 mA cm-2 at 0.4 V vs SHE could be obtained at pH 6.5 (Eonset = 0.72 V). UV-visible and Resonance Raman spectroelectrochemical studies suggest the formation of a high valent iron-oxo species as the catalytic intermediate. Our findings demonstrate the potential of multiheme cytochromes to catalyze technologically relevant reactions and establish MtrC as a new benchmark in biotechnological H2O2 reduction with scope for applications in fuel cells and biosensors.
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Affiliation(s)
- Bertrand Reuillard
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
| | - Khoa H. Ly
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
| | - Peter Hildebrandt
- Institut
für Chemie, Technische Universität
Berlin, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Lars J. C. Jeuken
- School
of Biomedical Sciences and the Astbury Centre, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Julea N. Butt
- School
of
Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Erwin Reisner
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
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34
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Beales PA, Khan S, Muench SP, Jeuken LJC. Durable vesicles for reconstitution of membrane proteins in biotechnology. Biochem Soc Trans 2017; 45:15-26. [PMID: 28202656 PMCID: PMC5310719 DOI: 10.1042/bst20160019] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 10/14/2016] [Accepted: 10/19/2016] [Indexed: 12/31/2022]
Abstract
The application of membrane proteins in biotechnology requires robust, durable reconstitution systems that enhance their stability and support their functionality in a range of working environments. Vesicular architectures are highly desirable to provide the compartmentalisation to utilise the functional transmembrane transport and signalling properties of membrane proteins. Proteoliposomes provide a native-like membrane environment to support membrane protein function, but can lack the required chemical and physical stability. Amphiphilic block copolymers can also self-assemble into polymersomes: tough vesicles with improved stability compared with liposomes. This review discusses the reconstitution of membrane proteins into polymersomes and the more recent development of hybrid vesicles, which blend the robust nature of block copolymers with the biofunctionality of lipids. These novel synthetic vesicles hold great promise for enabling membrane proteins within biotechnologies by supporting their enhanced in vitro performance and could also contribute to fundamental biochemical and biophysical research by improving the stability of membrane proteins that are challenging to work with.
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Affiliation(s)
- Paul A Beales
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K.
| | - Sanobar Khan
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K
| | - Stephen P Muench
- School of Biomedical Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K
| | - Lars J C Jeuken
- School of Biomedical Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K
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35
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Ainsworth EV, Lockwood CWJ, White GF, Hwang ET, Sakai T, Gross MA, Richardson DJ, Clarke TA, Jeuken LJC, Reisner E, Butt JN. Cover Picture: Photoreduction of Shewanella oneidensis
Extracellular Cytochromes by Organic Chromophores and Dye-Sensitized TiO2
(ChemBioChem 24/2016). Chembiochem 2016. [DOI: 10.1002/cbic.201600602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Emma V. Ainsworth
- School of Chemistry; University of East Anglia; Norwich Research Park Norfolk NR4 7TJ UK
| | - Colin W. J. Lockwood
- School of Chemistry; University of East Anglia; Norwich Research Park Norfolk NR4 7TJ UK
| | - Gaye F. White
- School of Biological Sciences; University of East Anglia; Norwich Research Park Norfolk NR4 7TJ UK
| | - Ee Taek Hwang
- School of Biomedical Sciences; University of Leeds; Leeds LS2 9JT UK
| | - Tsubasa Sakai
- Department of Chemistry; University of Cambridge; Lensfield Road Cambridge CB2 1EW UK
- Present address: Suntory Foundation for Life Sciences; Kyoto 619-0284 Japan
| | - Manuela A. Gross
- Department of Chemistry; University of Cambridge; Lensfield Road Cambridge CB2 1EW UK
| | - David J. Richardson
- School of Biological Sciences; University of East Anglia; Norwich Research Park Norfolk NR4 7TJ UK
| | - Thomas A. Clarke
- School of Biological Sciences; University of East Anglia; Norwich Research Park Norfolk NR4 7TJ UK
| | - Lars J. C. Jeuken
- School of Biomedical Sciences; University of Leeds; Leeds LS2 9JT UK
| | - Erwin Reisner
- Department of Chemistry; University of Cambridge; Lensfield Road Cambridge CB2 1EW UK
| | - Julea N. Butt
- School of Chemistry; University of East Anglia; Norwich Research Park Norfolk NR4 7TJ UK
- School of Biological Sciences; University of East Anglia; Norwich Research Park Norfolk NR4 7TJ UK
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36
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Ainsworth EV, Lockwood CWJ, White GF, Hwang ET, Sakai T, Gross MA, Richardson DJ, Clarke TA, Jeuken LJC, Reisner E, Butt JN. Photoreduction of Shewanella oneidensis Extracellular Cytochromes by Organic Chromophores and Dye-Sensitized TiO 2. Chembiochem 2016; 17:2324-2333. [PMID: 27685371 PMCID: PMC5215560 DOI: 10.1002/cbic.201600339] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Indexed: 12/28/2022]
Abstract
The transfer of photoenergized electrons from extracellular photosensitizers across a bacterial cell envelope to drive intracellular chemical transformations represents an attractive way to harness nature's catalytic machinery for solar-assisted chemical synthesis. In Shewanella oneidensis MR-1 (MR-1), trans-outer-membrane electron transfer is performed by the extracellular cytochromes MtrC and OmcA acting together with the outer-membrane-spanning porin⋅cytochrome complex (MtrAB). Here we demonstrate photoreduction of solutions of MtrC, OmcA, and the MtrCAB complex by soluble photosensitizers: namely, eosin Y, fluorescein, proflavine, flavin, and adenine dinucleotide, as well as by riboflavin and flavin mononucleotide, two compounds secreted by MR-1. We show photoreduction of MtrC and OmcA adsorbed on RuII -dye-sensitized TiO2 nanoparticles and that these protein-coated particles perform photocatalytic reduction of solutions of MtrC, OmcA, and MtrCAB. These findings provide a framework for informed development of strategies for using the outer-membrane-associated cytochromes of MR-1 for solar-driven microbial synthesis in natural and engineered bacteria.
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Affiliation(s)
- Emma V. Ainsworth
- School of ChemistryUniversity of East AngliaNorwich Research ParkNorfolkNR4 7TJUK
| | - Colin W. J. Lockwood
- School of ChemistryUniversity of East AngliaNorwich Research ParkNorfolkNR4 7TJUK
| | - Gaye F. White
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorfolkNR4 7TJUK
| | - Ee Taek Hwang
- School of Biomedical SciencesUniversity of LeedsLeedsLS2 9JTUK
| | - Tsubasa Sakai
- Department of ChemistryUniversity of CambridgeLensfield RoadCambridgeCB2 1EWUK
- Present address: Suntory Foundation for Life SciencesKyoto619-0284Japan
| | - Manuela A. Gross
- Department of ChemistryUniversity of CambridgeLensfield RoadCambridgeCB2 1EWUK
| | - David J. Richardson
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorfolkNR4 7TJUK
| | - Thomas A. Clarke
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorfolkNR4 7TJUK
| | | | - Erwin Reisner
- Department of ChemistryUniversity of CambridgeLensfield RoadCambridgeCB2 1EWUK
| | - Julea N. Butt
- School of ChemistryUniversity of East AngliaNorwich Research ParkNorfolkNR4 7TJUK
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorfolkNR4 7TJUK
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37
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Khan S, Li M, Muench SP, Jeuken LJC, Beales PA. Durable proteo-hybrid vesicles for the extended functional lifetime of membrane proteins in bionanotechnology. Chem Commun (Camb) 2016; 52:11020-3. [PMID: 27540604 PMCID: PMC5048396 DOI: 10.1039/c6cc04207d] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Significant enhancement of membrane protein functional durability is demonstrated when reconstituted in hybrid lipid–block copolymer vesicles compared to conventional proteoliposomes.
The full capabilities of membrane proteins in bionanotechnology can only be realised through improvements in their reconstitution environments that combine biocompatibility to support function and durability for long term stability. We demonstrate that hybrid vesicles composed of natural phospholipids and synthetic diblock copolymers have the potential to achieve these criteria.
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Affiliation(s)
- Sanobar Khan
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK.
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38
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Ye S, Benz F, Wheeler MC, Oram J, Baumberg JJ, Cespedes O, Christenson HK, Coletta PL, Jeuken LJC, Markham AF, Critchley K, Evans SD. One-step fabrication of hollow-channel gold nanoflowers with excellent catalytic performance and large single-particle SERS activity. Nanoscale 2016; 8:14932-14942. [PMID: 27352044 DOI: 10.1039/c6nr04045d] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Hollow metallic nanostructures have shown potential in various applications including catalysis, drug delivery and phototherapy, owing to their large surface areas, reduced net density, and unique optical properties. In this study, novel hollow gold nanoflowers (HAuNFs) consisting of an open hollow channel in the center and multiple branches/tips on the outer surface are fabricated for the first time, via a facile one-step synthesis using an auto-degradable nanofiber as a bifunctional template. The one-dimensional (1D) nanofiber acts as both a threading template as well as a promoter of the anisotropic growth of the gold crystal, the combination of which leads to the formation of HAuNFs with a hollow channel and nanospikes. The synergy of favorable structural/surface features, including sharp edges, open cavity and high-index facets, provides our HAuNFs with excellent catalytic performance (activity and cycling stability) coupled with large single-particle SERS activity (including ∼30 times of activity in ethanol electro-oxidation and ∼40 times of single-particle SERS intensity, benchmarked against similar-sized solid gold nanospheres with smooth surfaces, as well as retaining 86.7% of the initial catalytic activity after 500 cycles in ethanol electro-oxidation). This innovative synthesis gives a nanostructure of the geometry distinct from the template and is extendable to fabricating other systems for example, hollow-channel silver nanoflowers (HAgNFs). It thus provides an insight into the design of hollow nanostructures via template methods, and offers a versatile synthetic strategy for diverse metal nanomaterials suited for a broad range of applications.
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Affiliation(s)
- Sunjie Ye
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK. and Leeds Institute for Biomedical and Clinical Sciences, University of Leeds, Leeds, LS9 7TF, UK
| | - Felix Benz
- NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge Cambridge, CB3 0HE, UK
| | - May C Wheeler
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK.
| | - Joseph Oram
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK.
| | - Jeremy J Baumberg
- NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge Cambridge, CB3 0HE, UK
| | - Oscar Cespedes
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK.
| | - Hugo K Christenson
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK.
| | - Patricia Louise Coletta
- Leeds Institute for Biomedical and Clinical Sciences, University of Leeds, Leeds, LS9 7TF, UK
| | - Lars J C Jeuken
- School of Biomedical Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Alexander F Markham
- Leeds Institute for Biomedical and Clinical Sciences, University of Leeds, Leeds, LS9 7TF, UK
| | - Kevin Critchley
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK.
| | - Stephen D Evans
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK.
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39
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Wiebalck S, Kozuch J, Forbrig E, Tzschucke CC, Jeuken LJC, Hildebrandt P. Monitoring the Transmembrane Proton Gradient Generated by Cytochrome bo3 in Tethered Bilayer Lipid Membranes Using SEIRA Spectroscopy. J Phys Chem B 2016; 120:2249-56. [DOI: 10.1021/acs.jpcb.6b01435] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Swantje Wiebalck
- Institut
für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, D-14195 Berlin, Germany
| | - Jacek Kozuch
- Institut
für Chemie, Technische Universität Berlin, Straße des
17. Juni 135, D-10623 Berlin, Germany
| | - Enrico Forbrig
- Institut
für Chemie, Technische Universität Berlin, Straße des
17. Juni 135, D-10623 Berlin, Germany
| | - C. Christoph Tzschucke
- Institut
für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, D-14195 Berlin, Germany
| | - Lars J. C. Jeuken
- School of Biomedical Sciences, the Astbury Centre for Structural Molecular Biology, and School of Physics & Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Peter Hildebrandt
- Institut
für Chemie, Technische Universität Berlin, Straße des
17. Juni 135, D-10623 Berlin, Germany
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40
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Oram J, Jeuken LJC. A Re-evaluation of Electron-Transfer Mechanisms in Microbial Electrochemistry: Shewanella Releases Iron that Mediates Extracellular Electron Transfer. ChemElectroChem 2016; 3:829-835. [PMID: 27668145 PMCID: PMC5021177 DOI: 10.1002/celc.201500505] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Indexed: 12/11/2022]
Abstract
Exoelectrogenic bacteria can couple their metabolism to extracellular electron acceptors, including macroscopic electrodes, and this has applications in energy production, bioremediation and biosensing. Optimisation of these technologies relies on a detailed molecular understanding of extracellular electron‐transfer (EET) mechanisms, and Shewanella oneidensis MR‐1 (MR‐1) has become a model organism for such fundamental studies. Here, cyclic voltammetry was used to determine the relationship between the surface chemistry of electrodes (modified gold, ITO and carbon electrodes) and the EET mechanism. On ultra‐smooth gold electrodes modified with self‐assembled monolayers containing carboxylic‐acid‐terminated thiols, an EET pathway dominates with an oxidative catalytic onset at 0.1 V versus SHE. Addition of iron(II)chloride enhances the catalytic current, whereas the siderophore deferoxamine abolishes this signal, leading us to conclude that this pathway proceeds via an iron mediated electron transfer mechanism. The same EET pathway is observed at other electrodes, but the onset potential is dependent on the electrolyte composition and electrode surface chemistry. EET pathways with onset potentials above −0.1 V versus SHE have previously been ascribed to direct electron‐transfer (DET) mechanisms through the surface exposed decaheme cytochromes (MtrC/OmcA) of MR‐1. In light of the results reported here, we propose that the previously identified DET mechanism of MR‐1 needs to be re‐evaluated.
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Affiliation(s)
- Joseph Oram
- School of Biomedical Sciences and the Astbury Centre for Structural Molecular Biology University of Leeds Leeds LS2 9JT UK
| | - Lars J C Jeuken
- School of Biomedical Sciences and the Astbury Centre for Structural Molecular Biology University of Leeds Leeds LS2 9JT UK
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41
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Radu V, Frielingsdorf S, Lenz O, Jeuken LJC. Reactivation from the Ni–B state in [NiFe] hydrogenase of Ralstonia eutropha is controlled by reduction of the superoxidised proximal cluster. Chem Commun (Camb) 2016; 52:2632-5. [DOI: 10.1039/c5cc10382g] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The tolerance towards oxic conditions of O2-tolerant [NiFe] hydrogenases has been attributed to an unusual [4Fe–3S] cluster that lies proximal to the [NiFe] active site.
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Affiliation(s)
- Valentin Radu
- School of Biomedical Sciences
- The Astbury Centre for Structural Molecular Biology
- University of Leeds
- Leeds LS2 9JT
- UK
| | - Stefan Frielingsdorf
- Institut für Chemie
- Sekretariat PC14
- Technische Universität Berlin
- 10623 Berlin
- Germany
| | - Oliver Lenz
- Institut für Chemie
- Sekretariat PC14
- Technische Universität Berlin
- 10623 Berlin
- Germany
| | - Lars J. C. Jeuken
- School of Biomedical Sciences
- The Astbury Centre for Structural Molecular Biology
- University of Leeds
- Leeds LS2 9JT
- UK
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42
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Li M, Jørgensen SK, McMillan DGG, Krzemiński Ł, Daskalakis NN, Partanen RH, Tutkus M, Tuma R, Stamou D, Hatzakis NS, Jeuken LJC. Single Enzyme Experiments Reveal a Long-Lifetime Proton Leak State in a Heme-Copper Oxidase. J Am Chem Soc 2015; 137:16055-63. [PMID: 26618221 PMCID: PMC4697922 DOI: 10.1021/jacs.5b08798] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Heme-copper oxidases (HCOs) are key
enzymes in prokaryotes and
eukaryotes for energy production during aerobic respiration. They
catalyze the reduction of the terminal electron acceptor, oxygen,
and utilize the Gibbs free energy to transport protons across a membrane
to generate a proton (ΔpH) and electrochemical gradient termed
proton motive force (PMF), which provides the driving force for the
adenosine triphosphate (ATP) synthesis. Excessive PMF is known to
limit the turnover of HCOs, but the molecular mechanism of this regulatory
feedback remains relatively unexplored. Here we present a single-enzyme
study that reveals that cytochrome bo3 from Escherichia coli, an HCO closely homologous
to Complex IV in human mitochondria, can enter a rare, long-lifetime
leak state during which proton flow is reversed. The probability of
entering the leak state is increased at higher ΔpH. By rapidly
dissipating the PMF, we propose that this leak state may enable cytochrome bo3, and possibly other HCOs, to maintain a suitable
ΔpH under extreme redox conditions.
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Affiliation(s)
- Mengqiu Li
- School of Biomedical Sciences, University of Leeds , LS2 9JT Leeds, U.K
| | - Sune K Jørgensen
- Department of Chemistry, Nano-Science Center and Lundbeck Foundation Center for Biomembranes in Nanomedicine, University of Copenhagen , 2100 Copenhagen, Denmark
| | | | - Łukasz Krzemiński
- School of Biomedical Sciences, University of Leeds , LS2 9JT Leeds, U.K
| | | | - Riitta H Partanen
- School of Biomedical Sciences, University of Leeds , LS2 9JT Leeds, U.K
| | - Marijonas Tutkus
- Department of Chemistry, Nano-Science Center and Lundbeck Foundation Center for Biomembranes in Nanomedicine, University of Copenhagen , 2100 Copenhagen, Denmark
| | - Roman Tuma
- School of Molecular and Cellular Biology, University of Leeds , LS2 9JT Leeds, U.K
| | - Dimitrios Stamou
- Department of Chemistry, Nano-Science Center and Lundbeck Foundation Center for Biomembranes in Nanomedicine, University of Copenhagen , 2100 Copenhagen, Denmark
| | - Nikos S Hatzakis
- Department of Chemistry, Nano-Science Center and Lundbeck Foundation Center for Biomembranes in Nanomedicine, University of Copenhagen , 2100 Copenhagen, Denmark
| | - Lars J C Jeuken
- School of Biomedical Sciences, University of Leeds , LS2 9JT Leeds, U.K
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43
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Heath GR, Li M, Polignano IL, Richens JL, Catucci G, O’Shea P, Sadeghi SJ, Gilardi G, Butt JN, Jeuken LJC. Layer-by-Layer Assembly of Supported Lipid Bilayer Poly-l-Lysine Multilayers. Biomacromolecules 2015; 17:324-35. [DOI: 10.1021/acs.biomac.5b01434] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- George R. Heath
- School
of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Mengqiu Li
- School
of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | | | - Joanna L. Richens
- Cell
Biophysics Group, Institute of Biophysics, Imaging and Optical Science,
School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Gianluca Catucci
- Life
Sciences and Systems Biology, University of Torino, 10123, Turin, Italy
| | - Paul O’Shea
- Cell
Biophysics Group, Institute of Biophysics, Imaging and Optical Science,
School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Sheila J. Sadeghi
- Life
Sciences and Systems Biology, University of Torino, 10123, Turin, Italy
| | - Gianfranco Gilardi
- Life
Sciences and Systems Biology, University of Torino, 10123, Turin, Italy
| | - Julea N. Butt
- Centre
for Molecular and Structural Biochemistry, School of Biological Sciences,
and School of Chemistry, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Lars J. C. Jeuken
- School
of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
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44
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Hwang ET, Sheikh K, Orchard KL, Hojo D, Radu V, Lee CY, Ainsworth E, Lockwood C, Gross MA, Adschiri T, Reisner E, Butt JN, Jeuken LJC. A Decaheme Cytochrome as a Molecular Electron Conduit in Dye-Sensitized Photoanodes. Adv Funct Mater 2015; 25:2308-2315. [PMID: 26180522 PMCID: PMC4493899 DOI: 10.1002/adfm.201404541] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 02/05/2015] [Indexed: 06/04/2023]
Abstract
In nature, charge recombination in light-harvesting reaction centers is minimized by efficient charge separation. Here, it is aimed to mimic this by coupling dye-sensitized TiO2 nanocrystals to a decaheme protein, MtrC from Shewanella oneidensis MR-1, where the 10 hemes of MtrC form a ≈7-nm-long molecular wire between the TiO2 and the underlying electrode. The system is assembled by forming a densely packed MtrC film on an ultra-flat gold electrode, followed by the adsorption of approximately 7 nm TiO2 nanocrystals that are modified with a phosphonated bipyridine Ru(II) dye (RuP). The step-by-step construction of the MtrC/TiO2 system is monitored with (photo)electrochemistry, quartz-crystal microbalance with dissipation (QCM-D), and atomic force microscopy (AFM). Photocurrents are dependent on the redox state of the MtrC, confirming that electrons are transferred from the TiO2 nanocrystals to the surface via the MtrC conduit. In other words, in these TiO2/MtrC hybrid photodiodes, MtrC traps the conduction-band electrons from TiO2 before transferring them to the electrode, creating a photobioelectrochemical system in which a redox protein is used to mimic the efficient charge separation found in biological photosystems.
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Affiliation(s)
- Ee Taek Hwang
- School of Biomedical Sciences, University of Leeds Leeds, LS2 9JT, UK E-mail: ; The Astbury Centre for Structural Molecular Biology, University of Leeds Leeds, LS2 9JT, UK
| | - Khizar Sheikh
- School of Biomedical Sciences, University of Leeds Leeds, LS2 9JT, UK E-mail: ; The Astbury Centre for Structural Molecular Biology, University of Leeds Leeds, LS2 9JT, UK
| | - Katherine L Orchard
- Department of Chemistry, University of Cambridge Lensfield Road, Cambridge, CB2 1EW, UK E-mail: ; Advanced Institute for Materials Research, Tohoku University 2-1-1 Katahira Aoba-ku Sendai, Miyagi, 980-8577, Japan E-mail:
| | - Daisuke Hojo
- Advanced Institute for Materials Research, Tohoku University 2-1-1 Katahira Aoba-ku Sendai, Miyagi, 980-8577, Japan E-mail:
| | - Valentin Radu
- School of Biomedical Sciences, University of Leeds Leeds, LS2 9JT, UK E-mail: ; The Astbury Centre for Structural Molecular Biology, University of Leeds Leeds, LS2 9JT, UK
| | - Chong-Yong Lee
- Department of Chemistry, University of Cambridge Lensfield Road, Cambridge, CB2 1EW, UK E-mail:
| | - Emma Ainsworth
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia Norwich Research Park, Norwich, NR4 7TJ, UK E-mail:
| | - Colin Lockwood
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia Norwich Research Park, Norwich, NR4 7TJ, UK E-mail:
| | - Manuela A Gross
- Department of Chemistry, University of Cambridge Lensfield Road, Cambridge, CB2 1EW, UK E-mail:
| | - Tadafumi Adschiri
- Advanced Institute for Materials Research, Tohoku University 2-1-1 Katahira Aoba-ku Sendai, Miyagi, 980-8577, Japan E-mail:
| | - Erwin Reisner
- Department of Chemistry, University of Cambridge Lensfield Road, Cambridge, CB2 1EW, UK E-mail:
| | - Julea N Butt
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia Norwich Research Park, Norwich, NR4 7TJ, UK E-mail:
| | - Lars J C Jeuken
- School of Biomedical Sciences, University of Leeds Leeds, LS2 9JT, UK E-mail: ; The Astbury Centre for Structural Molecular Biology, University of Leeds Leeds, LS2 9JT, UK
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45
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Radu V, Frielingsdorf S, Evans SD, Lenz O, Jeuken LJC. Enhanced oxygen-tolerance of the full heterotrimeric membrane-bound [NiFe]-hydrogenase of Ralstonia eutropha. J Am Chem Soc 2014; 136:8512-5. [PMID: 24866391 PMCID: PMC4073834 DOI: 10.1021/ja503138p] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Hydrogenases are oxygen-sensitive enzymes that catalyze the conversion between protons and hydrogen. Water-soluble subcomplexes of membrane-bound [NiFe]-hydrogenases (MBH) have been extensively studied for applications in hydrogen-oxygen fuel cells as they are relatively tolerant to oxygen, although even these catalysts are still inactivated in oxidative conditions. Here, the full heterotrimeric MBH of Ralstonia eutropha, including the membrane-integral cytochrome b subunit, was investigated electrochemically using electrodes modified with planar tethered bilayer lipid membranes (tBLM). Cyclic voltammetry and chronoamperometry experiments show that MBH, in equilibrium with the quinone pool in the tBLM, does not anaerobically inactivate under oxidative redox conditions. In aerobic environments, the MBH is reversibly inactivated by O2, but reactivation was found to be fast even under oxidative redox conditions. This enhanced resistance to inactivation is ascribed to the oligomeric state of MBH in the lipid membrane.
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Affiliation(s)
- Valentin Radu
- School of Biomedical Sciences, the Astbury Centre for Structural Molecular Biology, and School of Physics & Astronomy, University of Leeds , Leeds LS2 9JT, United Kingdom
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46
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Mu Q, David CA, Galceran J, Rey-Castro C, Krzemiński L, Wallace R, Bamiduro F, Milne SJ, Hondow NS, Brydson R, Vizcay-Barrena G, Routledge MN, Jeuken LJC, Brown AP. Systematic investigation of the physicochemical factors that contribute to the toxicity of ZnO nanoparticles. Chem Res Toxicol 2014; 27:558-67. [PMID: 24575710 DOI: 10.1021/tx4004243] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
ZnO nanoparticles (NPs) are prone to dissolution, and uncertainty remains whether biological/cellular responses to ZnO NPs are solely due to the release of Zn(2+) or whether the NPs themselves have additional toxic effects. We address this by establishing ZnO NP solubility in dispersion media (Dulbecco's modified Eagle's medium, DMEM) held under conditions identical to those employed for cell culture (37 °C, 5% CO2, and pH 7.68) and by systematic comparison of cell-NP interaction for three different ZnO NP preparations. For NPs at concentrations up to 5.5 μg ZnO/mL, dissolution is complete (with the majority of the soluble zinc complexed to dissolved ligands in the medium), taking ca. 1 h for uncoated and ca. 6 h for polymer coated ones. Above 5.5 μg/mL, the results are consistent with the formation of zinc carbonate, keeping the solubilized zinc fixed to 67 μM of which only 0.45 μM is as free Zn(2+), i.e., not complexed to dissolved ligands. At these relatively high concentrations, NPs with an aliphatic polyether-coating show slower dissolution (i.e., slower free Zn(2+) release) and reprecipitation kinetics compared to those of uncoated NPs, requiring more than 48 h to reach thermodynamic equilibrium. Cytotoxicity (MTT) and DNA damage (Comet) assay dose-response curves for three epithelial cell lines suggest that dissolution and reprecipitation dominate for uncoated ZnO NPs. Transmission electron microscopy combined with the monitoring of intracellular Zn(2+) concentrations and ZnO-NP interactions with model lipid membranes indicate that an aliphatic polyether coat on ZnO NPs increases cellular uptake, enhancing toxicity by enabling intracellular dissolution and release of Zn(2+). Similarly, we demonstrate that needle-like NP morphologies enhance toxicity by apparently frustrating cellular uptake. To limit toxicity, ZnO NPs with nonacicular morphologies and coatings that only weakly interact with cellular membranes are recommended.
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Affiliation(s)
- Qingshan Mu
- School of Biomedical Sciences, University of Leeds , LS2 9JT Leeds, U.K
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47
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McMillan DGG, Marritt SJ, Kemp GL, Gordon-Brown P, Butt JN, Jeuken LJC. The Impact of Enzyme Orientation and Electrode Topology on the Catalytic Activity of Adsorbed Redox Enzymes. Electrochim Acta 2013; 110:79-85. [PMID: 24634538 DOI: 10.1016/j.electacta.2013.01.153] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
It is well established that the structural details of electrodes and their interaction with adsorbed enzyme influences the interfacial electron transfer rate. However, for nanostructured electrodes, it is likely that the structure also impacts on substrate flux near the adsorbed enzymes and thus catalytic activity. Furthermore, for enzymes converting macro-molecular substrates it is possible that the enzyme orientation determines the nature of interactions between the adsorbed enzyme and substrate and therefore catalytic rates. In essence the electrode may impede substrate access to the active site of the enzyme. We have tested these possibilities through studies of the catalytic performance of two enzymes adsorbed on topologically distinct electrode materials. Escherichia coli NrfA, a nitrite reductase, was adsorbed on mesoporous, nanocrystalline SnO2 electrodes. CymA from Shewanella oneidensis MR-1 reduces menaquinone-7 within 200 nm sized liposomes and this reaction was studied with the enzyme adsorbed on SAM modified ultra-flat gold electrodes.
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Affiliation(s)
- Duncan G G McMillan
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom. ; School of Physics & Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Sophie J Marritt
- Centre for Molecular and Structural Biochemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom. ; School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Gemma L Kemp
- Centre for Molecular and Structural Biochemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom. ; School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Piers Gordon-Brown
- Centre for Molecular and Structural Biochemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom. ; School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Julea N Butt
- Centre for Molecular and Structural Biochemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom. ; School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom. ; School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Lars J C Jeuken
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom. ; School of Physics & Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom
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48
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McMillan DGG, Marritt SJ, Firer-Sherwood MA, Shi L, Richardson DJ, Evans SD, Elliott SJ, Butt JN, Jeuken LJC. Protein-protein interaction regulates the direction of catalysis and electron transfer in a redox enzyme complex. J Am Chem Soc 2013; 135:10550-6. [PMID: 23799249 PMCID: PMC3823026 DOI: 10.1021/ja405072z] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
![]()
Protein–protein interactions
are well-known to regulate
enzyme activity in cell signaling and metabolism. Here, we show that
protein–protein interactions regulate the activity of a respiratory-chain
enzyme, CymA, by changing the direction or bias of catalysis. CymA,
a member of the widespread NapC/NirT superfamily, is a menaquinol-7
(MQ-7) dehydrogenase that donates electrons to several distinct terminal
reductases in the versatile respiratory network of Shewanella oneidensis. We report the incorporation
of CymA within solid-supported membranes that mimic the inner membrane
architecture of S. oneidensis. Quartz-crystal
microbalance with dissipation (QCM-D) resolved the formation of a
stable complex between CymA and one of its native redox partners,
flavocytochrome c3 (Fcc3) fumarate reductase.
Cyclic voltammetry revealed that CymA alone could only reduce MQ-7,
while the CymA-Fcc3 complex catalyzed the reaction required
to support anaerobic respiration, the oxidation of MQ-7. We propose
that MQ-7 oxidation in CymA is limited by electron transfer to the
hemes and that complex formation with Fcc3 facilitates
the electron-transfer rate along the heme redox chain. These results
reveal a yet unexplored mechanism by which bacteria can regulate multibranched
respiratory networks through protein–protein interactions.
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Affiliation(s)
- Duncan G G McMillan
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
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Booth M, Peel R, Partanen R, Hondow N, Vasilca V, Jeuken LJC, Critchley K. Amphipol-encapsulated CuInS2/ZnS quantum dots with excellent colloidal stability. RSC Adv 2013. [DOI: 10.1039/c3ra43846e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Mu Q, Hondow NS, Krzemiński L, Brown AP, Jeuken LJC, Routledge MN. Mechanism of cellular uptake of genotoxic silica nanoparticles. Part Fibre Toxicol 2012; 9:29. [PMID: 22823932 PMCID: PMC3479067 DOI: 10.1186/1743-8977-9-29] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 07/12/2012] [Indexed: 12/30/2022] Open
Abstract
Mechanisms for cellular uptake of nanoparticles have important implications for nanoparticulate drug delivery and toxicity. We have explored the mechanism of uptake of amorphous silica nanoparticles of 14 nm diameter, which agglomerate in culture medium to hydrodynamic diameters around 500 nm. In HT29, HaCat and A549 cells, cytotoxicity was observed at nanoparticle concentrations ≥ 1 μg/ml, but DNA damage was evident at 0.1 μg/ml and above. Transmission electron microscopy (TEM) combined with energy-dispersive X-ray spectroscopy confirmed entry of the silica particles into A549 cells exposed to 10 μg/ml of nanoparticles. The particles were observed in the cytoplasm but not within membrane bound vesicles or in the nucleus. TEM of cells exposed to nanoparticles at 4°C for 30 minutes showed particles enter cells when activity is low, suggesting a passive mode of entry. Plasma lipid membrane models identified physical interactions between the membrane and the silica NPs. Quartz crystal microbalance experiments on tethered bilayer lipid membrane systems show that the nanoparticles strongly bind to lipid membranes, forming an adherent monolayer on the membrane. Leakage assays on large unilamellar vesicles (400 nm diameter) indicate that binding of the silica NPs transiently disrupts the vesicles which rapidly self-seal. We suggest that an adhesive interaction between silica nanoparticles and lipid membranes could cause passive cellular uptake of the particles.
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Affiliation(s)
- Qingshan Mu
- Centre for Molecular NanoScience (CMNS), University of Leeds, Leeds LS2 9JT, UK
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