Recent advances in understanding blue copper proteins

Solomon, Edward I.; Hadt, Ryan G.

doi:10.1016/j.ccr.2010.12.008

Cited by 158 publications

(158 citation statements)

References 107 publications

(127 reference statements)

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“…However, enzyme-catalyzed cathodes are more efficient [266]. Multiple copper oxidases appear highly relevant in scientific literature, especially laccases, due to their high reduction potential, capacity to utilize multi-atomic reaction sites, flexibility of interatomic distances and the positive influence of residues adjacent to the active site on reaction mechanism [263,[267][268][269][270]. Laccases from fungal origin are most extensively studied due to the higher redox potential (~0.58 V vs Ag/ AgCl), ligand co-ordination geometry, and the presence of weakly axially co-ordinated residues contributing to the difference in redox potential [30].…”

Section: Cathodic Reduction Reactionsmentioning

confidence: 99%

Enzymatic Electrosynthesis: An Overview on the Progress in Enzyme- Electrodes for the Production of Electricity, Fuels and Chemicals

Satyawali¹

2013

J Microbial Biochem Technol

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Recent interest in the field of biocommodities production through bioelectrochemical systems has generated interest in the enzyme catalyzed redox reactions. Enzyme catalyzed electrodes are well established as sensors and power generators. However, a paradigm shift in recent science towards the production of useful chemicals has changed the face of biofuel cells, keeping the fuels or chemicals production in the upfront. This review article comprehensively presents the progress in the field of enzyme-electrodes for the production of electricity, fuels and chemicals with an aim to represent a practical outline for understanding the use of single or multiple redox enzymes as electrocatalysts for their electron transfer onto electrodes. It also provides the state-of-the-art information regarding the different existing processes to fabricate enzyme electrodes. Successfully-achieved electroenzymatic anodic and cathodic reactions are further discussed, together with their potential applications. Particular focus was made on the novel single/multiple enzyme systems towards product synthesis and other applications. Finally, techno-economic and environmental elements for industrial processing with enzyme catalyzed bioelectrochemical system (e-BES) are anticipated, in order to provide useful strategies for further development of this technology.

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Section: Cathodic Reduction Reactionsmentioning

confidence: 99%

Enzymatic Electrosynthesis: An Overview on the Progress in Enzyme- Electrodes for the Production of Electricity, Fuels and Chemicals

Satyawali¹

2013

J Microbial Biochem Technol

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“…In particular, intense peaks , which constitute in general the fingerprint of the RR spectra of T1 copper sites, can be assigned to the mixing of the Cu-S(Cys) stretching vibration with multiple heavy atom bending modes of the ligand and adjacent residues [30][31][32][33]. POXC RR vibrational features are rather similar to those observed in some laccases and blue copper proteins, characterized by similar organization of the copper active site [30][31][32][33][34]. Slight modulations in the positions of the main peaks could be related to differences in the T1 copper site as well as in the surrounding protein matrix.…”

Section: Resultsmentioning

confidence: 70%

Ultrafast excited-state charge-transfer dynamics in laccase type I copper site

Delfino

Viola

Cerullo

et al. 2015

Biophysical Chemistry

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• T1Cu MLCT in POXC is described by ultrafast pump-probe spectroscopy • The first step of the charge-transfer in POXC occurs within 375 fs • Ground-state coherent oscillations are compared to Resonance Raman features • The trigonal T1 Cu site geometry hypothesized for POXC is confirmed by the results G R A P H I C A L A B S T R A C Ta b s t r a c t a r t i c l e i n f o Femtosecond pump-probe spectroscopy was used to investigate the excited state dynamics of the T1 copper site of laccase from Pleurotus ostreatus, by exciting its 600 nm charge transfer band with a 15-fs pulse and probing over a broad range in the visible region. The decay of the pump-induced ground-state bleaching occurs in a single step and is modulated by clearly visible oscillations. Global analysis of the two-dimensional differential transmission map shows that the excited state exponentially decays with a time constant of 375 fs, thus featuring a decay rate slower than those occurring in quite all the investigated T1 copper site proteins. The ultrashort pump pulse induces a vibrational coherence in the protein, which is mainly assigned to ground state activity, as expected in a system with fast excited state decay. Vibrational features are discussed also in comparison with the traditional resonance Raman spectrum of the enzyme. The results indicate that both excited state dynamics and vibrational modes associated with the T1 Cu laccase charge transfer have main characteristics similar to those of all the T1 copper site-containing proteins. On the other hand, the differences observed for laccase from P. ostreatus further confirm the peculiar hypothesized trigonal T1 Cu site geometry.

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“…Paz contains a single type I ''blue copper'' center, a cofactor involved in a variety of biological electron transfer processes. The characteristic blue color is a result of charge transfer transitions from a coordinating cysteinate sulfur atom to the d 9 Cu(II) ion [40]. One-electron reduction to the Cu(I) (d 10 ) precludes charge transfer and bleaches the color, abolishing both CD and MCD.…”

Section: Testing Of Electrochemical Cell By Potentiometric Titrationsmentioning

confidence: 99%

Electrochemical titrations and reaction time courses monitored in situ by magnetic circular dichroism spectroscopy

Bradley

Butt

Cheesman

2011

Analytical Biochemistry

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a b s t r a c tMagnetic circular dichroism (MCD) spectra, at ultraviolet-visible or near-infrared wavelengths (185-2000 nm), contain the same transitions observed in conventional absorbance spectroscopy, but their bisignate nature and more stringent selection rules provide greatly enhanced resolution. Thus, they have proved to be invaluable in the study of many transition metal-containing proteins. For mainly technical reasons, MCD has been limited almost exclusively to the measurement of static samples. But the ability to employ the resolving power of MCD to follow changes at transition metal sites would be a potentially significant advance. We describe here the development of a cuvette holder that allows reagent injection and sample mixing within the 50-mm-diameter ambient temperature bore of an energized superconducting solenoid. This has allowed us, for the first time, to monitor time-resolved MCD resulting from in situ chemical manipulation of a metalloprotein sample. Furthermore, we report the parallel development of an electrochemical cell using a three-electrode configuration with physically separated working and counter electrodes, allowing true potentiometric titration to be performed within the bore of the MCD solenoid.Ó 2011 Elsevier Inc. All rights reserved.Magnetic circular dichroism (MCD) 1 spectroscopy, at ultraviolet-visible and near-infrared wavelengths (185-2000 nm), has proved to be invaluable in the study of metalloproteins containing cofactors such as heme [1][2][3], non-heme iron [4], iron-sulfur clusters [5][6][7][8], cobalt [9,10], nickel [11][12][13], and copper [14,15]. The technique measures the apparent circular dichroism (CD) induced by a magnetic field [16]. Despite similarities in the instrumentation used, the observation of MCD is not dependent on the chirality of the protein; the method is equally applicable to racemic model complexes [17]. The magnetic field will always induce signals across wavelengths at which the substance absorbs. Thus, MCD spectra contain the same electronic transitions observed in conventional absorbance spectroscopy, but the bisignate nature of the spectrum provides enhanced resolution and greater detail. This spectral detail offers an unmatched fingerprinting capability that can, for example, identify the spin and oxidation states of heme groups [1] and distinguish among the variety of iron-sulfur centers found in biological molecules [18][19][20].Metalloprotein MCD can be measured at ambient or cryogenic temperatures. The latter requires adulteration with glassing agents [16] but has generally been preferred because MCD intensity from paramagnetic centers increases dramatically at low temperature. Thus, most metalloprotein MCD reported has been measured in glasses at temperatures of approximately 4.2 K. Hemoproteins represent the significant exception, giving rise to appreciable MCD at high temperatures [1]. Thus, ambient temperature MCD is used to diagnose spin state, oxidation state, and (in the case of low-spin Fe(III) hemes) axial ligation [21].As ...

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Recent advances in understanding blue copper proteins

Cited by 158 publications

References 107 publications

Enzymatic Electrosynthesis: An Overview on the Progress in Enzyme- Electrodes for the Production of Electricity, Fuels and Chemicals

Enzymatic Electrosynthesis: An Overview on the Progress in Enzyme- Electrodes for the Production of Electricity, Fuels and Chemicals

Ultrafast excited-state charge-transfer dynamics in laccase type I copper site

Electrochemical titrations and reaction time courses monitored in situ by magnetic circular dichroism spectroscopy

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