Pulsed EPR studies of the type 2 copper binding site in the mercury derivative of laccase

Lü, Jinfeng; Bender, Christopher J.; McCracken, John; Peisach, Jack; Severns, John C.; McMillin, David R.

doi:10.1021/bi00142a014

Cited by 29 publications

(34 citation statements)

References 41 publications

(54 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Morpurgo and coworkers44 originally reported changes in the EPR features of this center between room temperature and 77K, as later studied by McMillin21,41,54 and Sakurai 42,43. At room temperature, the EPR parameters reflected a tetrahedral distortion of the metal site, and (surprisingly) a 70% reduction in the intensity of the EPR signal.…”

Section: Resultsmentioning

confidence: 90%

NMR Study of the Exchange Coupling in the Trinuclear Cluster of the Multicopper Oxidase Fet3p

et al. 2010

View full text Add to dashboard Cite

Fet3p from Saccharomyces cerevisiae is a multicopper oxidase (MCO) which oxidizes Fe 2+ to Fe 3+ . The electronic structure of the different copper centers in this family of enzymes has been extensively studied and discussed for years with a particular focus on the exchange coupling regime in the trinuclear cluster (TNC). Using NMR spectroscopy we have quantified the exchange coupling constant in the type 3 center in a fully metallated oxidase; this value in Fet3p is significantly higher than that reported for proteins containing isolated type 3 centers as in tyrosinase. We also provide evidence of exchange coupling between the type 2 and the type 3 Cu 2+ ions, which supports the crystallographic evidence of dioxygen binding to the TNC. This work provides the foundation for the application of NMR to these complex systems.

show abstract

Section: Resultsmentioning

confidence: 90%

NMR Study of the Exchange Coupling in the Trinuclear Cluster of the Multicopper Oxidase Fet3p

et al. 2010

View full text Add to dashboard Cite

show abstract

“…The frequencies between 2.3 and 3.2 also show little field dependence and are equal to the sums of quadrupolar frequencies. These combination frequencies are present when more than one imidazole is bound to the same Cu 2ϩ (Lu et al, 1992). The frequencies of the peaks at 3.8 -4.2 MHz increased as a function of magnetic field and were therefore assigned as double-quantum peaks.…”

Section: Eseem Data For Pmmo In M Capsulatus (Bath) and M Album Bg8mentioning

confidence: 98%

“…The intensities of the quadrupolar combination bands increase as the number of coordinated imidazoles increases (Lu et al, 1992). Based on comparison of the intensities of the quadrupolar combination bands observed for pMMO in intact cells (Fig.…”

Section: Eseem Data For Pmmo In M Capsulatus (Bath) and M Album Bg8mentioning

confidence: 99%

Comparison of EPR-Visible Cu2+ Sites in pMMO from Methylococcus capsulatus (Bath) and Methylomicrobium album BG8

Lemos

Collins

Eaton

et al. 2000

Biophysical Journal

View full text Add to dashboard Cite

X-band (9.1 GHz) and S-band (3.4 GHz) electron paramagnetic resonance (EPR) spectra for particulate methane monooxygenase (pMMO) in whole cells from Methylococcus capsulatus (Bath) grown on (63)Cu and (15)N were obtained and compared with previously reported spectra for pMMO from Methylomicrobium album BG8. For both M. capsulatus (Bath) and M. album BG8, two nearly identical Cu(2+) EPR signals with resolved hyperfine coupling to four nitrogens are observed. The EPR parameters for pMMO from M. capsulatus (Bath) (g( parallel) = 2.244, A( parallel) = 185 G, and A(N) = 19 G for signal one; g( parallel) = 2.246, A( parallel) = 180 G, and A(N) = 19 G for signal two) and for pMMO from M. album BG8 (g( parallel) = 2.243, A( parallel) = 180 G, and A(N) = 18 G for signal one; g( parallel) = 2. 251, A( parallel) = 180 G, and A(N) = 18 G for signal two) are very similar and are characteristic of type 2 Cu(2+) in a square planar or square pyramidal geometry. In three-pulse electron spin echo envelope modulation (ESEEM) data for natural-abundance samples, nitrogen quadrupolar frequencies due to the distant nitrogens of coordinated histidine imidazoles were observed. The intensities of the quadrupolar combination bands indicate that there are three or four coordinated imidazoles, which implies that most, if not all, of the coordinated nitrogens detected in the continuous wave spectra are from histidine imidazoles.

show abstract

“…The CuT 1 is attached to a sulfur atom belonging to a cysteine residue, with two imidazole rings of histidine residues, and one sulfur atom of the methionine residue. The Cut 2 is linked to at least two imidazole groups of the histidine residues [88]. The CuT3 are bonded to three nitrogen atoms, of which at least one is an imidazole group of the histidine residue, and another ligand, which can be H 2 O or OH [41,44,60,67,156].…”

Section: Laccasementioning

confidence: 99%

Enzyme Immobilization by Amperometric Biosensors with TiO2 Nanoparticles Used to Detect Phenol Compounds

et al. 2015

View full text Add to dashboard Cite

Nanoparticles of titanium dioxide (TiO 2 ) have unique properties in creating an appropriate microenvironment for immobilizing biomolecules without loss of biological activity, and facilitating electron transference between the enzyme and surface of the electrode. TiO 2 properties have led to its intensive use in building electrochemical biosensors. Another aspect is, the chemical process of sol-gel which offers new and interesting advantages in the encapsulation of biomolecules sensitive to heat and environmental conditions (enzymes, proteins, antibodies, and cells from plants, animals and micro-organisms), mainly due to a synthesized process at low temperatures. The nanomaterials produced by sol-gel have many advantages, including chemical inertia, physical rigidity, insignificant swelling in an aqueous medium, and porosity. For this reason, electrochemical biosensors consisting of nanomaterials have been extensively investigated and used in important industrial sectors, such as, those of pharmaceuticals, health, food, agriculture, and environment. They provide real-time data, which allows the control and traceability of each of the processes involved. Biosensors are devices that consist of one element of molecular recognition (biomolecules) and one transduction element. The objective of this work is to conduct a review of electrochemical biosensors using nanoparticles obtained from the sol-gel process and their potential application to measure phenol compounds.

show abstract

Pulsed EPR studies of the type 2 copper binding site in the mercury derivative of laccase

Cited by 29 publications

References 41 publications

NMR Study of the Exchange Coupling in the Trinuclear Cluster of the Multicopper Oxidase Fet3p

NMR Study of the Exchange Coupling in the Trinuclear Cluster of the Multicopper Oxidase Fet3p

Comparison of EPR-Visible Cu2+ Sites in pMMO from Methylococcus capsulatus (Bath) and Methylomicrobium album BG8

Enzyme Immobilization by Amperometric Biosensors with TiO2 Nanoparticles Used to Detect Phenol Compounds

Contact Info

Product

Resources

About