A5058374577- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Hemoglobin structure and function
- Metal-Catalyzed Oxygenation Mechanisms
- Photosynthetic Processes and Mechanisms
- Heme Oxygenase-1 and Carbon Monoxide
- Tryptophan and brain disorders
- Porphyrin and Phthalocyanine Chemistry
- Metal complexes synthesis and properties
- Porphyrin Metabolism and Disorders
- Enzyme Structure and Function
- melanin and skin pigmentation
- Photoreceptor and optogenetics research
- Spectroscopy Techniques in Biomedical and Chemical Research
- RNA regulation and disease
- Electron Spin Resonance Studies
- Neonatal Health and Biochemistry
- Mitochondrial Function and Pathology
- Biochemical Analysis and Sensing Techniques
- Metalloenzymes and iron-sulfur proteins
- Crystallography and molecular interactions
- Mass Spectrometry Techniques and Applications
- Alcoholism and Thiamine Deficiency
- Metabolomics and Mass Spectrometry Studies
- ATP Synthase and ATPases Research
University of Hyogo
2015-2024
Hyogo University
2011-2019
Newcastle University
2003-2012
SPring-8
2010
Argonne National Laboratory
2010
Ibaraki University
2002-2008
University College Dublin
2008
Max Planck Institute of Biochemistry
2007
Abstract The dinuclear copper enzyme, tyrosinase, activates O 2 to form a (μ‐η :η ‐p eroxido)dicopper(II) species, which hydroxylates phenols catechols. However, the exact mechanism of phenolase reaction in catalytic site tyrosinase is still under debate. We herein report near atomic resolution X‐ray crystal structures active tyrosinases with substrate l ‐tyrosine. At their sites, CuA moved toward ‐tyrosine (CuA1 → CuA2), whose phenol oxygen directly coordinates CuA2, involving movement CuB...
Bovine cytochrome c oxidase (CcO), a 420-kDa membrane protein, pumps protons using electrostatic repulsion between transferred through water channel and net positive charges created by oxidation of heme (Fe ) for reduction O2 at a3 a3). For this process to function properly, timing is essential: The must be closed after collection the pumped before Fe oxidation. If were remain open, spontaneous backflow collected would occur. elucidation closure mechanism, opening channel, which occurs upon...
Tyrosinase (EC 1.14.18.1), a copper-containing monooxygenase, catalyzes the conversion of phenol to corresponding ortho-quinone. The Streptomyces tyrosinase is generated as complex with “caddie” protein that facilitates transport two copper ions into active center. In our previous study, Tyr98 residue in caddie protein, which accommodated pocket center tyrosinase, has been found be converted reactive quinone through formations μ-η2:η2-peroxo-dicopper(II) and Cu(II)-dopasemiquinone...
Abstract Low body temperature predicts a poor outcome in patients with heart failure, but the underlying pathological mechanisms and implications are largely unknown. Brown adipose tissue (BAT) was initially characterised as thermogenic organ, recent studies have suggested it plays crucial role maintaining systemic metabolic health. While these reports suggest potential link between BAT of dysfunction failure has not been investigated. Here, we demonstrate that alteration function...
The Phe114Pro mutation to the cupredoxin azurin (AZ) leads a number of structural changes at active site attributed deletion one hydrogen bonds Cys112 ligand, removal bulky phenyl group from hydrophobic patch protein, and steric interactions made by introduced Pro. remaining bond between coordinating thiolate backbone amide Asn47 is strengthened. At type-1 copper site, CuII−O(Gly45) axial interaction decreases, while metal moves out plane formed equatorial His46, Cys112, His117 ligands,...
Synechocystis PCC 6803 has a high demand for iron (10 times greater than Escherichia coli) to sustain photosynthesis and is unusual in possessing at least two putative iron-binding proteins of type normally associated with ATP-binding cassette-type importers. It been suggested that one these, FutA2, binds ferrous iron, but herein we clearly demonstrate this protein avidly Fe(III), the oxidation state preference periplasmic proteins. Structures apo-FutA2 Fe-FutA2 have determined 1.7 2.7A,...
A hypochloritoiron(III) porphyrin species has been proposed as a key intermediate in an antimicrobial defense system neutrophils and heme-catalyzed chlorination reactions. We report herein the preparation, spectroscopic characterization, reactivity of bis(hypochlorito)iron(III) complex [(TPFP)Fe(III)(OCl)(2)](-) (1) imidazole-hypochloritoiron complexes (TPFP)Fe(III)(OCl)(1-R-Im) [R = CH(3) (2), H (3), CH(2)CO(2)H (4)], which TPFP is 5,10,15,20-tetrakis(pentafluorophenyl)porphyrinate. The...
A set of nickel(III) peroxo complexes bearing tetraazamacrocyclic ligands, [NiIII(TBDAP)(O2)]+ (TBDAP = N,N′-di-tert-butyl-2,11-diaza[3.3](2,6)pyridinophane) and [NiIII(CHDAP)(O2)]+ (CHDAP N,N′-dicyclohexyl-2,11-diaza[3.3](2,6)pyridinophane), were prepared by reacting [NiII(TBDAP)(NO3)(H2O)]+ [NiII(CHDAP)(NO3)]+, respectively, with H2O2 in the presence triethylamine. The mononuclear fully characterized various physicochemical methods, such as UV–vis, electrospray ionization mass...
Significance The short-lived intermediate formed during the reduction of nitric oxide (NO) to nitrous (N 2 O) in denitrification, microbial anaerobic respiration, is a key state for understanding generation mechanism N O, known not only as greenhouse gas but also an ozone-depleting substance on global level. This paper combined state-of-the-art, time-resolved techniques, such flow-flash infrared spectroscopy and X-ray free electron laser-based crystallography, captured P450-type NO reductase...
To understand the roles of mitochondrial respiratory chain supercomplexes, methods for consistently separating and preparing supercomplexes must be established. this end, we solubilized from bovine heart mitochondria with digitonin then replaced amphipol (A8-35), an amphiphilic polymer. Afterward, were separated other complexes by sucrose density gradient centrifugation. Twenty-six grams myocardium yielded 3.2 mg amphipol-stabilized supercomplex. The purified analyzed based on their...
Heme binds selectively to the 3′-terminal G-quartet (G6 G-quartet) of an all parallel-stranded tetrameric G-quadruplex DNA, [d(TTAGGG)]4, form a heme–DNA complex. Complexes between [d(TTAGGG)]4 and series chemically modified hemes possessing heme Fe atom with variety electron densities were characterized in terms their peroxidase activities evaluate effect change density (ρFe) on activities. The activity complex decreased decreasing ρFe, supporting idea that is elicited through reaction...
Periplasmic substrate binding proteins are known for iron, zinc, manganese, nickel, and molybdenum but not copper. Synechocystis PCC 6803 requires copper thylakoid-localized plastocyanin cytochrome oxidase. Here we show that mutants deficient in a periplasmic protein FutA2 have low oxidase activity produce c6 when grown under conditions (150 nm) which wild-type cells use rather than c6. Anaerobic separation of extracts by two-dimensional native liquid chromatography followed metal analysis...
Autocatalytic formation of His-Cys cross-linkage in the enzyme active site tyrosinase from Aspergillus oryzae has been demonstrated to proceed by treatment apoenzyme with Cu(II) under aerobic conditions, where a (μ-η(2):η(2)-peroxo)dicopper(II) species suggested be involved as key reactive intermediate.
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...
Acid effects on the chemical properties of metal–oxygen intermediates have attracted much attention recently, such as enhanced reactivity high-valent metal(IV)–oxo species by binding proton(s) or Lewis acidic metal ion(s) in redox reactions. Herein, we report for first time proton an iron(V)–oxo complex bearing a negatively charged tetraamido macrocyclic ligand (TAML) oxygen atom transfer (OAT) and electron-transfer (ET) First, synthesized characterized mononuclear nonheme Fe(V)–oxo TAML (1)...
Mechanistic studies are performed on the alkane hydroxylation with m-CPBA (m-chloroperbenzoic acid) catalyzed by nickel(II) complexes, NiII (L). In oxidation of cycloalkanes, (TPA) acts as an efficient catalyst a high yield and alcohol selectivity. adamantane, tertiary carbon is predominantly oxidized. The reaction rate shows first-order dependence [substrate] [NiII (L)] but independent [m-CPBA]; vobs =k2 [substrate][NiII (L)]. exhibited relatively large kinetic deuterium isotope effect...
The influence of π-interactions with a His ligand have been investigated in family copper-containing redox metalloproteins. Met16Phe and Met16Trp pseudoazurin, Leu12Phe spinach Leu14Phe Phormidium laminosum plastocyanin variants possess active-site π-contacts between the introduced residue His81 His87/92 respectively. striking overlap side chain Phe16 variant that Met16 wild type pseudoazurin identifies this position provides an important second coordination sphere interaction both cases....
Abstract Resonance Raman spectroscopy has been applied to two distinct temporal species of indoleamine 2,3-dioxygenase during catalytic turnover. We have identified oxygen-isotope-sensitive modes at 569 and 798 cm−1 for the respective species. The 16O18O analysis band indicates existence a ferryl-oxo heme, which is inconsistent with previously proposed reaction mechanism. present study thus provides physical basis structures possible intermediates.
The main active-site loop of the copper-binding protein azurin (a cupredoxin) has been shortened from C(112)TFPGH(117)SALM(121) to C(112)TPH(115)PFM(118) (the native cupredoxin amicyanin) and also C(112)TPH(115)PM(117). Cu(II) site structure is almost unaffected by shortening, as that Cu(I) center at alkaline pH in variant with C(112)TPH(115)PM(117) sequence. Subtle spectroscopic differences due alterations spin density distribution can be attributed mainly changes hydrogen-bonding pattern....
Large assemblies of respiratory chain complexes, known as supercomplexes, are present in the mitochondrial membrane mammals and yeast, well some bacterial membranes. The formation supercomplexes is thought to contribute efficient electron transfer, stabilization each enzyme complex, inhibition reactive oxygen species (ROS) generation. In this study, mitochondria from various organisms were solubilized with digitonin, then complexes separated by blue native PAGE (BN-PAGE). results revealed a...
Abstract The dinuclear copper enzyme, tyrosinase, activates O 2 to form a (μ‐η :η ‐p eroxido)dicopper(II) species, which hydroxylates phenols catechols. However, the exact mechanism of phenolase reaction in catalytic site tyrosinase is still under debate. We herein report near atomic resolution X‐ray crystal structures active tyrosinases with substrate l ‐tyrosine. At their sites, CuA moved toward ‐tyrosine (CuA1 → CuA2), whose phenol oxygen directly coordinates CuA2, involving movement CuB...
Disproportionation of Cpd II models depends on the electron-richness porphyrin ligand; with an electron-deficient ligand is difficult to disproportionate, whereas electron-rich readily disproportionates form I as a true oxidant.
The peroxidase activity of cytochrome (cyt) c increases when Met80 dissociates from the heme iron, which is related to initial cyt membrane permeation step apoptosis. Met80-dissociated can form an oxygenated species. Herein, resonance Raman spectra Met80-depleted horse (M80A c) were analyzed elucidate ligand properties c. Fe–His stretching (νFe–His) mode ferrous M80A was observed at 236 cm–1, and this frequency decreased by 1.5 cm–1 for 15N-labeled protein. higher νFe–His than other...
The Met16Phe mutant of the type 1 copper protein pseudoazurin (PACu), in which a phenyl ring is introduced close to imidazole moiety His81 ligand, has been characterized. NMR studies indicate that parallel group His81. mutation subtle effect on position two S(Cys)-->Cu(II) ligand-to-metal charge transfer bands visible spectrum PACu(II) and more significant influence their intensities resulting A(459)/A(598) ratio 0.31 for as compared A(453)/A(594) 0.43 wild-type at pH 8. electron...
Resonance Raman (RR) spectra of the oxygenated and FeIVO reaction intermediates indoleamine 2,3-dioxygenase (IDO) are reported. Absorption RR reveal that electronic geometric structures two respective species at pH 6.5 8.0 same, although enzymatic activity is 6 times higher than 8.0. The results thus further support our current understanding heme active in IDO cycle, its presence was unexpected. Fe–O2 O–O stretching frequencies IDO-Trp-O2 ternary complex Trp concentrations 50 μM 8 mM...