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Jamal RB, Shipovskov S, Ferapontova EE. Electrochemical Immuno- and Aptamer-Based Assays for Bacteria: Pros and Cons over Traditional Detection Schemes. Sensors (Basel) 2020; 20:E5561. [PMID: 32998409 PMCID: PMC7582323 DOI: 10.3390/s20195561] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/15/2020] [Accepted: 09/23/2020] [Indexed: 01/20/2023]
Abstract
Microbiological safety of the human environment and health needs advanced monitoring tools both for the specific detection of bacteria in complex biological matrices, often in the presence of excessive amounts of other bacterial species, and for bacteria quantification at a single cell level. Here, we discuss the existing electrochemical approaches for bacterial analysis that are based on the biospecific recognition of whole bacterial cells. Perspectives of such assays applications as emergency-use biosensors for quick analysis of trace levels of bacteria by minimally trained personnel are argued.
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Affiliation(s)
| | | | - Elena E. Ferapontova
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University Gustav Wieds Vej 14, DK-8000 Aarhus, Denmark; (R.B.J.); (S.S.)
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2
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Pankratov D, Bendixen M, Shipovskov S, Gosewinkel U, Ferapontova EE. Cellulase-Linked Immunomagnetic Microbial Assay on Electrodes: Specific and Sensitive Detection of a Single Bacterial Cell. Anal Chem 2020; 92:12451-12459. [PMID: 32799451 DOI: 10.1021/acs.analchem.0c02262] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Pathogen-associated infections represent one of the major threats to human health and require reliable methods for immediate and robust identification of pathogenic microorganisms. Here, an inexpensive cellulase-linked immunomagnetic methodology was developed for the specific and ultrasensitive analysis of bacteria at their single-cell levels within a 3 h procedure. Detection of a model bacterium, Escherichia coli, was performed in a sandwich reaction with E. coli-specific either aptamer or antibody (Ab)-modified magnetic beads (MBs) and Ab/aptamer reporter molecules linked to cellulase. The cellulase-labeled immuno-aptamer sandwich applied onto nitrocellulose-film-modified electrodes digested the film and changed its electrical conductivity. Electrode's chronocoulometric responses at 0.3 V, in the absence of any redox indicators, allowed a single E. coli cell detection and from 1 to 4 × 104 CFU mL-1 E. coli quantification. No interference/cross-reactivity from Salmonella enteritidis, Enterobacter agglomerans, Pseudomonas putida, Staphylococcus aureus, and Bacillus subtilis was observed when the assay was performed on Ab-modified MBs, and E. coli could be quantified in tap water and milk. This electrochemically label-free methodology is sufficiently fast, highly specific, and sensitive to be used in direct in-field applications. The assay can be adapted for specific detection of other bacterial strains of either the same or different species and offers new analytical tools for fast, specific, and reliable analysis of bacteria in the clinic, food, and environment.
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Affiliation(s)
- Dmitrii Pankratov
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, Aarhus C DK-8000, Denmark
| | - Mads Bendixen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, Aarhus C DK-8000, Denmark
| | - Stepan Shipovskov
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, Aarhus C DK-8000, Denmark
| | - Ulrich Gosewinkel
- Department of Environmental Science, Aarhus University, Frederiksborgvej 399, Roskilde DK-4000, Denmark
| | - Elena E Ferapontova
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, Aarhus C DK-8000, Denmark
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3
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Jensen UB, Mohammad‐Beigi H, Shipovskov S, Sutherland DS, Ferapontova EE. Activation of Cellobiose Dehydrogenase Bioelectrocatalysis by Carbon Nanoparticles. ChemElectroChem 2019. [DOI: 10.1002/celc.201901066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Uffe Bjørnholt Jensen
- Interdisciplinary Nanoscience Center (iNANO)Aarhus University Gustav Wieds Vej 14 8000 Aarhus C Denmark
| | - Hossein Mohammad‐Beigi
- Interdisciplinary Nanoscience Center (iNANO)Aarhus University Gustav Wieds Vej 14 8000 Aarhus C Denmark
| | - Stepan Shipovskov
- Interdisciplinary Nanoscience Center (iNANO)Aarhus University Gustav Wieds Vej 14 8000 Aarhus C Denmark
| | - Duncan S. Sutherland
- Interdisciplinary Nanoscience Center (iNANO)Aarhus University Gustav Wieds Vej 14 8000 Aarhus C Denmark
| | - Elena E. Ferapontova
- Interdisciplinary Nanoscience Center (iNANO)Aarhus University Gustav Wieds Vej 14 8000 Aarhus C Denmark
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4
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Shipovskov S, Bonamore A, Boffi A, Ferapontova EE. Electrocatalytic interconversion of NADH and NAD(+) by Escherichia coli flavohemoglobin. Chem Commun (Camb) 2016; 51:16096-8. [PMID: 26389555 DOI: 10.1039/c5cc06317e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
E. coli flavohemoglobin, oriented at electrodes via amphiphilic polymyxin B, electrocatalytically interconverts NADH and NAD(+) at its heme potentials operating as an electron transfer relay between the electrode and the protein FAD, where NADH/NAD(+) is transformed. The results are crucial for the development of NAD(+)-dependent bioelectrodes for biosynthesis, biosensors and biofuel cells.
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Affiliation(s)
- S Shipovskov
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark.
| | - A Bonamore
- Department of Biochemical Sciences and CNR Institute of Molecular Biology and Pathology, University "La Sapienza", 00185 Rome, Italy
| | - A Boffi
- Department of Biochemical Sciences and CNR Institute of Molecular Biology and Pathology, University "La Sapienza", 00185 Rome, Italy
| | - E E Ferapontova
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark.
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Kékedy-Nagy L, Shipovskov S, Ferapontova EE. Effect of a Dual Charge on the DNA-Conjugated Redox Probe on DNA Sensing by Short Hairpin Beacons Tethered to Gold Electrodes. Anal Chem 2016; 88:7984-90. [DOI: 10.1021/acs.analchem.6b01020] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [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)
- László Kékedy-Nagy
- Interdisciplinary
Nanoscience Center, and ‡Center for DNA Nanotechnology at
iNANO, Science and Technology, Aarhus University, Gustav Wieds Vej 1590-14, DK-8000 Aarhus C, Denmark
| | - Stepan Shipovskov
- Interdisciplinary
Nanoscience Center, and ‡Center for DNA Nanotechnology at
iNANO, Science and Technology, Aarhus University, Gustav Wieds Vej 1590-14, DK-8000 Aarhus C, Denmark
| | - Elena E. Ferapontova
- Interdisciplinary
Nanoscience Center, and ‡Center for DNA Nanotechnology at
iNANO, Science and Technology, Aarhus University, Gustav Wieds Vej 1590-14, DK-8000 Aarhus C, Denmark
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Shipovskov S, Oliveira CLP, Hoffmann SV, Schauser L, Sutherland DS, Besenbacher F, Pedersen JS. Water-in-oil micro-emulsion enhances the secondary structure of a protein by confinement. Chemphyschem 2012; 13:3179-84. [PMID: 22730383 DOI: 10.1002/cphc.201200295] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Indexed: 11/10/2022]
Abstract
A scheme is presented in which an organic solvent environment in combination with surfactants is used to confine a natively unfolded protein inside an inverse microemulsion droplet. This type of confinement allows a study that provides unique insight into the dynamic structure of an unfolded, flexible protein which is still solvated and thus under near-physiological conditions. In a model system, the protein osteopontin (OPN) is used. It is a highly phosphorylated glycoprotein that is expressed in a wide range of cells and tissues for which limited structural analysis exists due to the high degree of flexibility and large number of post-translational modifications. OPN is implicated in tissue functions, such as inflammation and mineralisation. It also has a key function in tumour metastasis and progression. Circular dichroism measurements show that confinement enhances the secondary structural features of the protein. Small-angle X-ray scattering and dynamic light scattering show that OPN changes from being a flexible protein in aqueous solution to adopting a less flexible and more compact structure inside the microemulsion droplets. This novel approach for confining proteins while they are still hydrated may aid in studying the structure of a wide range of natively unfolded proteins.
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Affiliation(s)
- Stepan Shipovskov
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Ny Munkegade 8000 Aarhus, Denmark.
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Jensen UB, Lörcher S, Vagin M, Chevallier J, Shipovskov S, Koroleva O, Besenbacher F, Ferapontova EE. A 1.76V hybrid Zn-O2 biofuel cell with a fungal laccase-carbon cloth biocathode. Electrochim Acta 2012. [DOI: 10.1016/j.electacta.2011.12.026] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Wang J, Jensen UB, Jensen GV, Shipovskov S, Balakrishnan VS, Otzen D, Pedersen JS, Besenbacher F, Sutherland DS. Soft interactions at nanoparticles alter protein function and conformation in a size dependent manner. Nano Lett 2011; 11:4985-91. [PMID: 21981115 DOI: 10.1021/nl202940k] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Weak protein-nanoparticle (NP) interactions are studied in a low binding regime as a model for the soft protein corona around nanoparticles in complex biological fluids. Noncovalent, reversible interactions between Subtilisin Carlsberg (SC) and silica NPs shows significant alteration in conformation and enzymatic activity in a NP-size dependent manner. Very weak interactions between SC and silica NPs were revealed by centrifugation-based separations and further supported by small-angle X-ray scattering, while bovine serum albumin was used as a strongly interacting reference. Secondary and tertiary structure changes of SC were studied via circular dichroism and correlated to enzymatic activity where the enzyme kinetics showed a critical role for nanoparticle size.
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Affiliation(s)
- Jing Wang
- Interdisciplinary NanoscienceCenter (iNANO), Aarhus University, 7400 Herning, Denmark
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9
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Sedov SA, Belogurova NG, Shipovskov S, Levashov AV, Levashov PA. Lysis of Escherichia coli cells by lysozyme: discrimination between adsorption and enzyme action. Colloids Surf B Biointerfaces 2011; 88:131-3. [PMID: 21763113 DOI: 10.1016/j.colsurfb.2011.06.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Revised: 06/13/2011] [Accepted: 06/19/2011] [Indexed: 11/15/2022]
Abstract
The key factors of enzymatic lysis of cells are the interaction between the enzyme and the cell - catalytic and non-catalytic adsorption of enzyme on cell surface. Here, the studies of lysis of intact Escherichia coli cells by chicken egg white lysozyme were performed. It was found that the ionic strength has a dual effect onto the system. On the one hand, the desorption constant of the enzyme increases with the increase of the solution ionic strength, which results in a better enzyme performance. On the other hand, due to the higher osmosis, the cell lysis rate decreases with the increasing of ionic strength of the system. It was found that pH 8.6 and 30 mM NaCl are optimal conditions for lysis of E. coli cells by lysozyme.
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Affiliation(s)
- S A Sedov
- Department of Chemical Enzymology, Faculty of Chemistry, Moscow State University, Moscow, Russia
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Pinijsuwan S, Shipovskov S, Surareungchai W, Ferapontova EE, Gothelf KV. Development of a lipase-based optical assay for detection of DNA. Org Biomol Chem 2011; 9:6352-6. [DOI: 10.1039/c0ob01165g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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11
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Levashov PA, Sedov SA, Shipovskov S, Belogurova NG, Levashov AV. Quantitative turbidimetric assay of enzymatic gram-negative bacteria lysis. Anal Chem 2010; 82:2161-3. [PMID: 20136093 DOI: 10.1021/ac902978u] [Citation(s) in RCA: 28] [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: 11/30/2022]
Abstract
In this Technical Note, the quantitative turbidimetric assay for determination of the bacteriolytic activity of enzymes with gram-negative bacteria is proposed. The reactivity of hen white-egg lysozyme toward gram-negative E. coli intact cells was studied. It was found that the highest lysis rate occurred at pH 8.9 in the system containing 0.03 M NaCl. The mechanism of the reaction is discussed and applied for the quantitative evaluation of the reaction rate. The proposed method enables fast, reliable, and reproducible analysis of bacteriolytic activity of lysozyme with gram-negative bacteria.
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Affiliation(s)
- Pavel A Levashov
- Department of Chemical Enzymology, Chemical Faculty, Moscow State University, 119992 Moscow, Russia.
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12
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Ferapontova EE, Hansen MN, Saunders AM, Shipovskov S, Sutherland DS, Gothelf KV. Electrochemical DNA sandwich assay with a lipase label for attomole detection of DNA. Chem Commun (Camb) 2010; 46:1836-8. [PMID: 20198225 DOI: 10.1039/b924627d] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [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
A fast and sensitive electrochemical lipase-based sandwich hybridization assay for detection of attomole levels of DNA has been developed. A combination of magnetic beads, used for pre-concentration and bioseparation of the analyte with a lipase catalyst label allowed detection of DNA with a limit of 20 amol.
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Affiliation(s)
- Elena E Ferapontova
- Centre for DNA Nanotechnology, Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark.
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13
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Skovgaard J, Bak CA, Snabe T, Sutherland DS, Laursen BS, Kragh KM, Besenbacher F, Poulsen CH, Shipovskov S. Implementation of cross-linked enzyme aggregates of proteases for marine paint applications. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/c0jm01249a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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Kartashov AV, Serafini G, Dong M, Shipovskov S, Gazaryan I, Besenbacher F, Ferapontova EE. Long-range electron transfer in recombinant peroxidases anisotropically orientated on gold electrodes. Phys Chem Chem Phys 2010; 12:10098-107. [DOI: 10.1039/c0cp00605j] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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15
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Levashov PA, Sutherland DS, Besenbacher F, Shipovskov S. A robust method of determination of high concentrations of peptides and proteins. Anal Biochem 2009; 395:111-2. [DOI: 10.1016/j.ab.2009.08.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Revised: 08/10/2009] [Accepted: 08/16/2009] [Indexed: 10/20/2022]
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Shipovskov S, Ferapontova EE. Biocatalysis of theophylline oxidation by microbial theophylline oxidase in the presence of non-physiological electron acceptors. BIOCATAL BIOTRANSFOR 2009. [DOI: 10.1080/10242420802456639] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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18
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Shipovskov S, Kragh KM, Laursen BS, Poulsen CH, Besenbacher F, Sutherland DS. Mannanase transfer into hexane and xylene by liquid-liquid extraction. Appl Biochem Biotechnol 2009; 160:1124-9. [PMID: 19444389 DOI: 10.1007/s12010-009-8661-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2008] [Accepted: 04/28/2009] [Indexed: 10/20/2022]
Abstract
The formation of noncovalent complexes between glycosidase, endo-1,4-beta-D-mannanase, and ionic surfactant di(2-ethylhexyl) sodium sulfosuccinate (AOT) was shown to promote protein transfer into organic solvents such as xylene and hexane. It was found that mannanase can be solubilized in hexane and in xylene with concentration at least 2.5 and 2.0 mg/ml, respectively. The catalytic activity of the enzyme in hexane spontaneously increases with the concentration of AOT and is about 10% of the activity in aqueous system. In xylene, a catalytic activity higher than that in bulk aqueous conditions was found for the samples containing 0.1-0.3 mg/ml of mannanase, while for the samples with a higher concentration of enzyme, the activity was hardly detected.
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Affiliation(s)
- Stepan Shipovskov
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus C 8000, Denmark.
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Abstract
The purpose of this review is to draw attention to the use of electrospray ionization mass spectrometry (ESI-MS) for monitoring the course of enzyme-substrate interactions, in the particular case of complex systems in which two substrates participate. The determination and characterization of intra-molecular reactions, especially those that occur in the enzyme active site, is not a trivial task in chemical kinetics, typically requiring long measurement times and relatively expensive techniques such as nuclear magnetic resonance (NMR), X-ray crystallography or electron microscopy (EM). However, nowadays almost all laboratories are equipped with or else have access to the ESI-MS technique. The aim of this review is to focus on the possibilities of employing even quite simple MS equipment to tackle different applications in studies of complex enzymatic systems.
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Affiliation(s)
- Stepan Shipovskov
- Manchester Interdisciplinary Biocentre, University of Manchester, Manchester, UKM1 7DN.
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21
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Shipovskov S, Karlberg T, Fodje M, Hansson MD, Ferreira GC, Hansson M, Reimann CT, Al-Karadaghi S. Metallation of the Transition-state Inhibitor N-methyl Mesoporphyrin by Ferrochelatase: Implications for the Catalytic Reaction Mechanism. J Mol Biol 2005; 352:1081-90. [PMID: 16140324 DOI: 10.1016/j.jmb.2005.08.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2005] [Revised: 07/27/2005] [Accepted: 08/03/2005] [Indexed: 11/20/2022]
Abstract
Insertion of metals into various tetrapyrroles is catalysed by a group of enzymes called chelatases, e.g. nickel, cobalt, magnesium and ferro-chelatase. It has been proposed that catalytic metallation includes distorting the porphyrin substrate by the enzyme towards a transition state-like geometry in which at least one of the pyrrole rings will be available for metal chelation. Here, we present a study of metal insertion into the transition-state inhibitor of protoporphyrin IX ferrochelatase, N-methyl mesoporphyrin (N-MeMP), by time-resolved crystallography and mass spectrometry with and without the presence of ferrochelatase. The results show that metallation of N-MeMP has a very limited effect on the conformation of the residues that participate in porphyrin and metal binding. These findings support theoretical data, which indicate that product release is controlled largely by the strain created by metal insertion into the distorted porphyrin. The results suggest that, similar to non-catalytic metallation of N-MeMP, the ferrochelatase-assisted metallation depends on the ligand exchange rate for the respective metal. Moreover, ferrochelatase catalyses insertion of Cu(II) and Zn(II) into N-MeMP with a rate that is about 20 times faster than non-enzymatic metallation in solution, suggesting that the catalytic strategy of ferrochelatase includes a stage of acceleration of the rate of ligand exchange for the metal substrate. The greater efficiency of N-MeMP metallation by Cu(II), as compared to Zn(II), contrasts with the K(m) values for Zn(II) (17 microM) and Cu(II) (170 microM) obtained for metallation of protoporphyrin IX. We suggest that this difference in metal specificity depends on the type of distortion imposed by the enzyme on protoporphyrin IX, which is different from the intrinsic non-planar distortion of N-MeMP. A mechanism of control of metal specificity by porphyrin distortion may be general for different chelatases, and may have common features with the mechanism of metal specificity in crown ethers.
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Affiliation(s)
- Stepan Shipovskov
- Department of Molecular Biophysics, Centre for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
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Shipovskov S, Trofimova D, Saprykin E, Christenson A, Ruzgas T, Levashov AV, Ferapontova EE. Spraying Enzymes in Microemulsions of AOT in Nonpolar Organic Solvents for Fabrication of Enzyme Electrodes. Anal Chem 2005; 77:7074-9. [PMID: 16255612 DOI: 10.1021/ac050505d] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new technique suitable for automated, large-scale fabrication of enzyme electrodes by air-spraying enzymes in organic inks is presented. Model oxidoreductases, tyrosinase (Tyr) and glucose oxidase (GOx), were adapted to octane-based ink by entrapment in a system of reverse micelles (RM) of surfactant AOT in octane to separate and stabilize the catalytically active forms of the enzymes in nonpolar organic media. Nonpolar caoutchouk polymer was also used to create a kind of "dry micelles" at the electrode/solution interface. Enzyme/RM/polymer-containing organic inks were air-brushed onto conductive supports and were subsequently covered by sprayed Nafion membranes. The air-brushed enzyme electrodes exhibited relevant bioelectrocatalytic activity toward catechol and glucose, with a linear detection range of 0.1-100 microM catechol and 0.5-7 mM glucose; the sensitivities were 2.41 A M(-1) cm(-2) and 2.98 mA M(-1) cm(-2) for Tyr and GOx electrodes, respectively. The proposed technique of air-brushing enzymes in organic inks enables automated construction of disposable enzyme electrodes of various designs on a mass-production scale.
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Affiliation(s)
- Stepan Shipovskov
- Department of Molecular Biophysics, Lund University, SE-221 00 Lund, Sweden
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Meersman F, Dirix C, Shipovskov S, Klyachko NL, Heremans K. Pressure-induced protein unfolding in the ternary system AOT-octane-water is different from that in bulk water. Langmuir 2005; 21:3599-3604. [PMID: 15807607 DOI: 10.1021/la0470481] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In a cellular environment, the presence of macromolecular cosolutes and membrane interfaces can influence the folding-unfolding behavior of proteins. Here we report on the pressure stability of alpha-chymotrypsin in the ternary system bis(2-ethylhexyl)sodium sulfosuccinate-octane-water using FTIR spectroscopy. The ternary system forms anionic reverse micelles which mimic cellular conditions. We find that inclusion of a single protein molecule in a reverse micelle does not alter its conformation. When pressurized in bulk water, alpha-chymotrypsin unfolds at 750 MPa into a partially unfolded structure. In contrast, in the ternary system, the same pressure increase induces a random coil-like unfolded state, which collapses into an amorphous aggregate during the decompression phase. It is suggested that the unfolding pathway is different in a cell-mimicking environment due to the combined effect of multiple factors, including confinement. A phase transition of the reverse micellar to the lamellar phase is thought to be essential to provide the conditions required for unfolding and aggregation, though the unfolding is not a direct result of the phase transition. Our observations therefore suggest that membranes may cause the formation of alternative conformations that are more susceptible to aggregation.
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Affiliation(s)
- Filip Meersman
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom.
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Shipovskov S, Ferapontova EE, Gazaryan I, Ruzgas T. Recombinant horseradish peroxidase - and cytochrome c-based two-electrode system for detection of superoxide radicals. Bioelectrochemistry 2004; 63:277-80. [PMID: 15110287 DOI: 10.1016/j.bioelechem.2003.09.026] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2003] [Revised: 09/15/2003] [Accepted: 09/19/2003] [Indexed: 11/22/2022]
Abstract
The reliable detection of a superoxide anion radical O2(*-) is complicated by its spontaneous dismutation reaction to H2O2 at acidic pHs. To simultaneously detect both O2(*-) and H2O2 produced in the course of its spontaneous dismutation, an electrochemical two-electrode system based on cytochrome c (cyt c) and recombinant horseradish peroxidase (rHRP) was applied. Therewith, a limited applicability of the cyt c system for the reliable monitoring of O2(*-) in acidic and neutral solutions was shown. It was demonstrated that both the reaction of O2(*-) dismutation to H2O2 and the reaction between the formed H2O2 and O2(*-) chemically decrease the amount of the initially present O2(*-), decreasing the sensitivity and reliability of the electrochemical detection at acidic pH. However, by appropriately varying solution pH, the concentration of O2(*-) initially injected in the system can be estimated from the analysis of calibration curves for H2O2 obtained with highly sensitive rHRP-modified electrode system at pH 6.0 and 7.0.
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Affiliation(s)
- Stepan Shipovskov
- Department of Molecular Biophysics, Lund University, P.O. Box 124, Lund SE 22100, Sweden
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Abstract
Formation of noncovalent complexes between tyrosinase from mushrooms and a cationic polyelectrolyte, polybrene (PB, poly (1,5-dimethyl-1,5-diazaundecamethyelene) bromide), was shown to activate and stabilize tyrosinase in water-ethanol mixtures. In the reaction of catechol oxidation in aqueous solutions, catalytic activity (k(cat)) of tyrosinase-PB complex ([PB]/[tyrosinase] molar ratio 100:1, per mole of polymer) in a wide range of pH was higher than that of free tyrosinase. In aqueous solutions and in water-ethanol mixtures at moderate concentrations of ethanol (10-40% v/v), the value of k(cat) of tyrosinase-PB complex exceeded the activity of free enzyme, from 1.2-2-fold, accompanied by the essential (up to 10-fold) increase in the value of the specificity constant (k(cat)/K(m)). The results are of practical importance for the construction of biocatalysts working successfully in polar organic media.
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Affiliation(s)
- Stepan Shipovskov
- Department of Chemical Enzymology, Chemical Faculty, Moscow State University, 199899 Moscow, Russia
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Shipovskov S, Ferapontova E, Ruzgas T, Levashov A. Stabilisation of tyrosinase by reversed micelles for bioelectrocatalysis in dry organic media. Biochim Biophys Acta 2003; 1620:119-24. [PMID: 12595080 DOI: 10.1016/s0304-4165(02)00513-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The enzymatic and bioelectrocatalytic activity of tyrosinase from mushrooms was studied in a system of reversed micelles formed by Aerosol OT (AOT) in hexane. The optimal catechol oxidising activity of tyrosinase incorporated in reversed micelles was found at a hydration degree of w(0)=25. The catalytic activity was comparable with tyrosinase activity in aqueous media. When immobilized at an Au electrode, either directly or in reversed micelles, tyrosinase exhibited a similar efficiency of the bioelectrocatalytic reduction of O(2) mediated by catechol; however, a rapid decrease in the activity correlated with the destruction of reversed micelles and/or the removal of tyrosinase from the electrode surface. The system containing tyrosinase in reversed micelles with caoutchouk, spread on the surface of the Au electrode and successively covered with a Nafion membrane layer, was found to result in stable tyrosinase-modified electrodes, which were resistant to inactivation in dry acetonitrile. The proposed technique offers possibilities for further development of highly active and stable surfactant/enzyme-modified electrodes for measurements carried out in organic solvents.
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Affiliation(s)
- Stepan Shipovskov
- Department of Chemical Enzymology, Chemical Faculty, Moscow State University, Russia.
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