Electrochemical characterization of dehaloperoxidase adsorbates on COOH/OH mixed self-assembled monolayers

Chen, Thomas K.; Bowden, Edmond F.

doi:10.1016/j.jelechem.2013.05.023

Cited by 6 publications

(9 citation statements)

References 43 publications

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“…The proper re-engineering of the protein surface might lead the tight protein−protein complexation (the case of a "simple docking") and the essentially improved ET rate constant. 16,17 Very recently, by connecting the two earlier approaches, Bowden et al 55,56 considered links between the protein− protein and protein−SAM docking paradigms (implying liquidphase and interfacial assemblies, respectively) in the context of the impact of the docking strength on Mb's functional ability. They reported voltammetric studies on dehydroperoxidase (monomeric bacterial globin 57 ) long-range ET at Au electrodes modified by thicker mixed (−COOH/−OH)-terminated SAMs.…”

Section: ■ Introductionmentioning

confidence: 99%

“…They reported voltammetric studies on dehydroperoxidase (monomeric bacterial globin 57 ) long-range ET at Au electrodes modified by thicker mixed (−COOH/−OH)-terminated SAMs. 55,56 The subsequent analysis led to the necessity of considering the role of the protein's conformational dynamics in ET. A similar tentative conclusion was drawn in our preliminary short communication 58 reporting voltammetric studies of ET for horse muscle Mb tightly bound to mixed HS−(CH 2 ) 11 −COOH/HS−(CH 2 ) 11 −OH SAMs.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Very recently, by connecting the two earlier approaches, Bowden et al , considered links between the protein–protein and protein–SAM docking paradigms (implying liquid-phase and interfacial assemblies, respectively) in the context of the impact of the docking strength on Mb’s functional ability. They reported voltammetric studies on dehydroperoxidase (monomeric bacterial globin) long-range ET at Au electrodes modified by thicker mixed (−COOH/–OH)-terminated SAMs. , The subsequent analysis led to the necessity of considering the role of the protein’s conformational dynamics in ET. A similar tentative conclusion was drawn in our preliminary short communication reporting voltammetric studies of ET for horse muscle Mb tightly bound to mixed HS–(CH 2 ) 11 –COOH/HS–(CH 2 ) 11 –OH SAMs.…”

Section: Introductionmentioning

confidence: 99%

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Long-Range Electron Transfer with Myoglobin Immobilized at Au/Mixed-SAM Junctions: Mechanistic Impact of the Strong Protein Confinement

et al. 2014

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Horse muscle myoglobin (Mb) was tightly immobilized at Au-deposited ~15-Å-thick mixed-type (1:1) alkanethiol SAMs, HS-(CH₂)₁₁-COOH/HS-(CH₂)₁₁-OH, and placed in contact with buffered H₂O or D₂O solutions. Fast-scan cyclic voltammetry (CV) and a Marcus-equation-based analysis were applied to determine unimolecular standard rate constants and reorganization free energies for electron transfer (ET), under variable-temperature (15-55 °C) and -pressure (0.01-150 MPa) conditions. The CV signal was surprisingly stable and reproducible even after multiple temperature and pressure cycles. The data analysis revealed the following values: standard rate constant, 33 s⁻¹ (25 °C, 0.01 MPa, H₂O); reorganization free energy, 0.5 ± 0.1 eV (throughout); activation enthalpy, 12 ± 3 kJ mol⁻¹; activation volume, -3.1 ± 0.2 cm³ mol⁻¹; and pH-dependent solvent kinetic isotope effect (k(H)⁰/k(D)⁰), 0.7-1.4. Furthermore, the values for the rate constant and reorganization free energy are very similar to those previously found for cytochrome c electrostatically immobilized at the monocomponent Au/HS-(CH₂)₁₁-COOH junction. In vivo, Mb apparently forms a natural electrostatic complex with cytochrome b₅ (cyt-b₅) through the "dynamic" (loose) docking pattern, allowing for a slow ET that is intrinsically coupled to the water's removal from the "defective" heme iron (altogether shaping the biological repair mechanism for Mb's "met" form). In contrary, our experiments rather mimic the case of a "simple" (tight) docking of the redesigned (mutant) Mb with cyt-b₅ (Nocek et al. J. Am. Chem. Soc. 2010, 132, 6165-6175). According to our analysis, in this configuration, Mb's distal pocket (linked to the "ligand channel") seems to be arrested within the restricted configuration, allowing the rate-determining reversible ET process to be coupled only to the inner-sphere reorganization (minimal elongation/shortening of an Fe-OH₂ bond) rather than the pronounced detachment (rebinding) of water and, hence, to be much faster.

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Section: ■ Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Long-Range Electron Transfer with Myoglobin Immobilized at Au/Mixed-SAM Junctions: Mechanistic Impact of the Strong Protein Confinement

et al. 2014

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“…Furthermore, it has been well established that Mb, in general, is a rather flexible protein that is required for the realization of its function − ligand binding/release through the "gating" motion of the protein matrix throughout the region of the "ligand channel" [32][33][34][44][45][46][47][48]. However, strong confinement of proteins due to the solution glass-forming [35][36][37][38] or tight electrostatic immobilization involving terminal groups -OH and -COOH of 1 : 1 mixed SAM [22,83], seemingly, restricts the opening motions of the ligand channel and locks the Fe-coordinated ligand (water, in this particular case) in the bound condition. In general, it becomes obvious that there is some correlation between the stabilizing impact of Mb's environment and the ET efficiency.…”

Section: Kinetic Data On the Impact Of Temperaturementioning

confidence: 99%

Electron transfer with myoglobin in free and strongly confined regimes: disclosing diverse mechanistic role of the Fe-coordinated water by temperature- and pressure-assisted voltammetric studies

Dolidze

Shushanyan

Khoshtariya

2015

Journal of Coordination Chemistry

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The naturally occurring electron-transfer (ET) event for myoglobin (Mb) can be mimicked through its functionalization at diversely modified metal platforms to allow for the electron exchange either in freely diffusing or immobilized regimes. In this work, horse muscle Mb was involved in the electron exchange with Au electrodes modified by dissimilar, thin or thick alkanethiol SAMs, terminated either by unicomponent (-OH) or 1 : 1 mixed (-OH/-COOH) functional (externally exposed) entities, respectively. The systematic, temperature-and pressure-supported cyclic voltammetry studies perfectly confirmed certainty of two kinds of ET patterns for Mb, embodying: (a) different operational kinetic regimes (including protein's freely diffusing and strongly confined motifs) and (b) different intrinsic physical mechanisms (including dynamically controlled and nonadiabatic modes). Our analysis of obtained and published data for Mb and the reference redox-active protein, cytochrome c, specified further the central mechanistic role of the Fe-(heme-)coordinated water whose displacement is directly coupled to ET, and can be, in turn, controlled by the conformational organization and intrinsic fluctuational mobility of the Mb macromolecule.

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“…Binary SAMs formed from two components of thiols and/or disulfides are noteworthy for easily giving higher functionality in comparison with mono SAMs. Recently, several researchers have tried to use binary SAMs that create some space for bulky enzymes or antibodies to efficiently work [21], and for electron transfer [22], in addition to immobilization of proteins [23,24]. As far as we are aware, the application of the binary SAMs to ECL sensors has not been found in any research as yet.…”

Section: Introductionmentioning

confidence: 99%

Detection of influenza virus by a biosensor based on the method combining electrochemiluminescence on binary SAMs modified Au electrode with an immunoliposome encapsulating Ru (II) complex

et al. 2016

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Recently, point of care testing (POCT) used for diagnosis of influenza infection has a problem showing false negative diagnosis because of the low sensitivity. We would like to report detection of influenza virus A (H1N1) by an immunosensor based on electrochemiluminescence (ECL) that uses an immunoliposome encapsulating tris(2,2'-bipyridyl)ruthenium(II) complex. By using the sensor, we could detect the virus that competed with hemagglutinin (HA) peptide immobilized on self-assembled monolayers (SAMs) in immunoreaction of the antibody bound on the surface of liposome. The HA peptide was 19 mer (TGLRNGITNKVNSVIEKAA). We demonstrated great improvement of sensitivity and accuracy by introducing binary SAMs instead of mono SAMs. The binary SAMs was prepared from 3,3'-dithiodipropionic acid and 1-hexanethiol. Use of the binary SAMs enabled to increase the SAMs coverage on Au electrode; the fact was confirmed by observation of the cathodic desorption currents. By using such an electrode, first the detection method of BSA was optimized to lower ECL background signal. Then we applied the method to the detection of influenza virus. We could successfully detect the virus with higher sensitivity compared with that by POCT and ELISA. The detection range was from a concentration of 2.7 × 10(2) to 2.7 × 10(3) PFU/mL.

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Electrochemical characterization of dehaloperoxidase adsorbates on COOH/OH mixed self-assembled monolayers

Cited by 6 publications

References 43 publications

Long-Range Electron Transfer with Myoglobin Immobilized at Au/Mixed-SAM Junctions: Mechanistic Impact of the Strong Protein Confinement

Long-Range Electron Transfer with Myoglobin Immobilized at Au/Mixed-SAM Junctions: Mechanistic Impact of the Strong Protein Confinement

Electron transfer with myoglobin in free and strongly confined regimes: disclosing diverse mechanistic role of the Fe-coordinated water by temperature- and pressure-assisted voltammetric studies

Detection of influenza virus by a biosensor based on the method combining electrochemiluminescence on binary SAMs modified Au electrode with an immunoliposome encapsulating Ru (II) complex

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