A5023599155- Electrochemical Analysis and Applications
- Photosynthetic Processes and Mechanisms
- Electrochemical sensors and biosensors
- Hemoglobin structure and function
- Protein Structure and Dynamics
- Spectroscopy and Quantum Chemical Studies
- Enzyme-mediated dye degradation
- Neutrophil, Myeloperoxidase and Oxidative Mechanisms
- Metal complexes synthesis and properties
- Molecular Junctions and Nanostructures
- Porphyrin Metabolism and Disorders
- Metal-Catalyzed Oxygenation Mechanisms
- Chemical Analysis and Environmental Impact
- Trace Elements in Health
- Metalloenzymes and iron-sulfur proteins
- Nuclear physics research studies
- Arsenic contamination and mitigation
- Heme Oxygenase-1 and Carbon Monoxide
- Photoreceptor and optogenetics research
- Nitric Oxide and Endothelin Effects
- Water Treatment and Disinfection
- Analytical Chemistry and Sensors
- Fluoride Effects and Removal
- Lipid Membrane Structure and Behavior
- Enzyme Structure and Function
University of Modena and Reggio Emilia
2015-2024
Azienda Unita' Sanitaria Locale Di Modena
2020
Newcastle University
2010
Istituto di Chimica Biomolecolare
2006
University of Basilicata
1994-2006
BOKU University
2006
Leiden University
2001-2005
University of Leeds
2003
The Ohio State University
1999-2002
University of Bologna
1994-1997
Axial iron ligation and protein encapsulation of the heme cofactor have been investigated as effectors reduction potential (E°') cytochrome c through direct electrochemistry experiments. Our approach was that partitioning E°' changes resulting from binding imidazole, 2-methyl-imidazole, ammonia, azide to both microperoxidase-11 (MP11), into enthalpic entropic contributions. N-Acetylmethionine MP11 also investigated. These ligands replace Met80 a water molecule axially coordinated in MP11,...
The thermodynamic parameters of protein reduction (ΔH°'rc and ΔS°'rc) were measured for a number blue copper proteins including spinach plastocyanin, cucumber Pseudomonas aeruginosa azurin, Rhus vernicifera stellacyanin, horseradish umecyanin through voltammetric techniques in nonisothermal experiments at neutral pH. Including previous estimates other members the same family, we discuss here thermodynamics electron-exchange reaction twelve from different sources. enthalpic term (-ΔH°'rc/F)...
The reduction potentials of beef heart cytochrome c and cytochromes c2 from Rhodopseudomonas palustris, Rhodobacter sphaeroides, capsulatus were measured through direct electrochemistry at a surface-modified gold electrode as function temperature in nonisothermal experiments carried out neutral alkaline pH values. thermodynamic parameters for protein (ΔS°rc ΔH°rc) determined the native conformers. Enthalpy entropy terms underlying species-dependent differences E° pH- temperature-induced...
The binary and ternary (2,2'-bipyridine) complexes of dipositive lead formed by N-carbonyl N-sulfonyl amino acids, which are ligands containing the peptide sulfonamide group, respectively, were investigated in aqueous solution NMR differential pulse polarography, some also characterized crystallographically. N-Tosylglycine, N-tosyl-beta-alanine, N-benzoylglycine behave as simple carboxylate at acid pH, while around neutrality they switch to dianionic N,O-bidentate chelating due involvement...
Myeloperoxidase (MPO) (donor, hydrogen peroxide oxidoreductase, EC 1.11.1.7) is the most abundant neutrophil enzyme and catalyzes predominantly two-electron oxidation of ubiquitous chloride (Cl-), to generate potent bleaching oxidant hypochlorous acid (HOCl), thus contributing bacterial killing inflammatory reactions neutrophils. Here, thermodynamics one-electron reduction ferric heme in its high-spin cyanide-bound low-spin forms were determined through spectroelectrochemical experiments....
Cytochromes c (cytc) are ubiquitous heme-containing metalloproteins that shuttle electrons in a variety of electron-transport chains, most often central to the production chemical energy necessary for cell life. The reduction potential (E°′) Fe3+/2+ couple is physiological role these species it influences thermodynamic and kinetic features electron-exchange reactions with redox partners. In last two decades, voltammetric techniques exploiting heterogeneous electron exchange between cytc...
The thermodynamics of Fe3+ to Fe2+ reduction for the five-coordinate high-spin native form horseradish peroxidase and its six-coordinate low-spin cyanide adduct have been determined from variable-temperature UV−vis spectroelectrochemical experiments. In both cases, ΔH°'rc ΔS°'rc values are positive. Hence, negative potentials turn out be result two opposing partially compensating contributions: a large enthalpic term, which is determinant E°' species, smaller, yet relevant, entropic...
The reduction thermodynamics (ΔH°'rc and ΔS°'rc) for native Paracoccus versutus amicyanin, Alcaligenes faecalis S-6 pseudoazurin, the G45P, M64E, K27C variants of Pseudomonas aeruginosa azurin were measured electrochemically. Comparison with data available other mutated blue copper proteins indicates that features metal coordination electrostatic potential due to protein matrix solvent control enthalpy in a straightforward way. However, effects on are rather unpredictable owing entropic...
Cyclic voltammetry experiments were carried out on native Saccharomyces cerevisiae iso-1-cytochrome c and its C102T/N62C variant immobilized bare polycrystalline gold electrode through the S−Au bond formed by a surface cysteine. Experiments at different temperatures (5−65 °C) pH values (1.5−7). The E°' value 7 (+370 mV vs SHE) is approximately 100 higher than that for protein in solution. This difference enthalpic origin proposed to be result of electrostatic repulsion among densely packed...
Replacement of the axial Met80 heme ligand in electrode-immobilized cytochrome c with a noncoordinating Ala residue and alteration hydrogen bonding network region nearby following substitution Tyr67 were investigated as effectors thermodynamics kinetics protein−electrode electron transfer (ET) heme-mediated electrocatalytic reduction H2O2. To this end, voltammetry Met80Ala, Met80Ala/Tyr67His, Met80Ala/Tyr67Ala variants yeast iso-1-cytochrome chemisorbed on carboxyalkanethiol self-assembled...
Myeloperoxidase (MPO) is the most abundant neutrophil enzyme and catalyzes predominantly two-electron oxidation of ubiquitous chloride to generate potent bleaching hypochlorous acid, thus contributing pathogen killing as well inflammatory diseases. Its catalytic properties are closely related with unique posttranslational modifications its prosthetic group. In MPO, modified heme b covalently bound protein via two ester linkages one sulfonium ion linkage a strong impact on (electronic)...
The low-pH conformational equilibria of ferric yeast iso-1 cytochrome c (ycc) and its M80A, M80A/Y67H, M80A/Y67A variants were studied from pH 7 to 2 at low ionic strength through electronic absorption, magnetic circular dichroism, resonance Raman spectroscopies. For wild-type ycc, the protein structure, axial heme ligands, spin state iron atom convert native folded His/Met low-spin (LS) form a molten globule His/H(2)O high-spin (HS) totally unfolded bis-aquo HS state, in single cooperative...
The hydrophobic patch of azurin (AZ) from Pseudomonas aeruginosa is an important recognition surface for electron transfer (ET) reactions. influence changing the size this region, by mutating C-terminal copper-binding loop, on ET reactivity AZ adsorbed gold electrodes modified with alkanethiol self-assembled monolayers (SAMs) has been studied. distance-dependence kinetics measured cyclic voltammetry using SAMs variable chain length, demonstrates that activation barrier short-range dominated...
All phytopathogenic fungi have two catalase-peroxidase paralogues located either intracellularly (KatG1) or extracellularly (KatG2). Here, for the first time a secreted bifunctional, homodimeric (KatG2 from rice blast fungus Magnaporthe grisea) has been produced heterologously with almost 100% heme occupancy and comprehensively investigated by using broad set of methods including UV-Vis, ECD resonance Raman spectroscopy (RR), thin-layer spectroelectrochemistry, mass spectrometry,...
The heme enzyme chlorite dismutase (Cld) catalyzes the degradation of to chloride and dioxygen. Although structure steady-state kinetics Clds have been elucidated, many questions remain (e.g., mechanism cleavage pH dependence reaction). Here, we present high-resolution X-ray crystal structures a dimeric Cld at 6.5 8.5, its fluoride isothiocyanate complexes neutron 9.0 together with Fe(III)/Fe(II) couple, UV–vis resonance Raman spectral features. We demonstrate that distal Arg127 cannot act...
Chlorite dismutases (Clds) are heme b containing oxidoreductases that convert chlorite to chloride and molecular oxygen. In order elucidate the role of conserved cavity residues in catalysis this reaction comprehensive mutational biochemical analyses Cld from "Candidatus Nitrospira defluvii" (NdCld) were performed. Particularly, point mutations cavity-forming R173, K141, W145, W146, E210 The effect manipulation 12 single double mutants was probed by UV-vis spectroscopy,...
The redox potential of horse and bovine heart cytochromes c determined through cyclic voltammetry is exploited to probe for anion–protein interactions, using a Debye–Hückel‐based model. In parallel, protein charge neutralization resulting from specific anion binding allows monitoring surface‐charge/ E o relationships. This approach shows that number anions, most which are biological relevance, namely Cl ‐ , HPO 2‐ 4 HCO 3 NO SO ClO citrate 3‐ oxalate bind specifically the surface, often in...