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Yoshio Hisaeda

Publications and source records attributed to Yoshio Hisaeda.

At least 19 recordsLinked to original sources
PubMed2006

Crystal structure and peroxidase activity of myoglobin reconstituted with iron porphycene.

The incorporation of an artificially created metal complex into an apomyoglobin is one of the attractive methods in a series of hemoprotein modifications. Single crystals of sperm whale myoglobin reconstituted with 13,16-dicarboxyethyl-2,7-diethyl-3,6,12,17-tetramethylporphycenatoiron(III) were obtained in the imidazole buffer, and the 3D structure with a 2.25-A resolution indicates that the iron porphycene, a structural isomer of hemin, is located in the normal position of the heme pocket. Furthermore, it was found that the reconstituted myoglobin catalyzed the H2O2-dependent oxidations of substrates such as guaiacol, thioanisole, and styrene. At pH 7.0 and 20 degrees C, the initial rate of the guaiacol oxidation is 11-fold faster than that observed for the native myoglobin. Moreover, the stopped-flow analysis of the reaction of the reconstituted protein with H2O2 suggested the formation of two reaction intermediates, compounds II- and III-like species, in the absence of a substrate. It is a rare example that compound III is formed via compound II in myoglobin chemistry. The enhancement of the peroxidase activity and the formation of the stable compound III in myoglobin with iron porphycene mainly arise from the strong coordination of the Fe-His93 bond.

Animals↗
PubMed2006

1,1'-(Ethenylidene)bis(4-chlorobenzene).

The title compound, C14H10Cl2, crystallizes as colourless prisms with two symmetry-independent molecules in the unit cell. Numerous intermolecular C-H...pi interactions dominate in the crystal structure, where C-H...Cl and long Cl...Cl contacts are also observed.

Journal Article↗
PubMed2006

Iron porphyrin-cyclodextrin supramolecular complex as a functional model of myoglobin in aqueous solution.

The 1:1 inclusion complex of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphinato iron(II) (Fe(II)TPPS) and an O-methylated beta-cyclodextrin dimer having a pyridine linker (1) binds dioxygen reversibly in aqueous solution. The O2 adduct was very stable (t(1/2) = 30.1 h) at pH 7.0 and 25 degrees C. ESI-MS and NMR spectroscopic measurements and molecular mechanics (MM) calculations indicated the inclusion of the sulfonatophenyl groups at the 5- and 15-positions of Fe(III)TPPS or Fe(II)TPPS into two cyclodextrin moieties of 1 to form a supramolecular 1:1 complex (hemoCD1 for the Fe(II)TPPS complex), whose iron center is completely covered by two cyclodextrin moieties. Equilibrium measurements and laser flash photolysis provided the affinities ( and ) and rate constants for O2 and CO binding of hemoCD1 (k(O2)(on), k(O2)(off), k(CO)(on), and k(CO)(off)). The CO affinity relative to the O2 affinity of hemoCD1 was abnormally high. Although resonance Raman spectra suggested weak back-bonding of d(pi)(Fe) --> pi(CO) and hence a weak CO-Fe bond, the CO adduct of hemoCD1 was very stable. The hydrophobic CO molecule dissociated from CO-hemoCD1 hardly breaks free from a shallow cleft in hemoCD1 surrounded by an aqueous bulk phase leading to fast rebinding of CO to hemoCD1. Isothermal titration calorimetry furnished the association constant (K(O2)), DeltaH degrees , and DeltaS degrees for O2 association to be (2.71 +/- 0.51) x 10(4) M(-1), -65.2 +/- 4.4 kJ mol(-1), and -133.9 +/- 16.1 J mol(-1) K(-1), respectively. The autoxidation of oxy-hemoCD1 was accelerated by H+ and OH-. The inorganic anions also accelerated the autoxidation of oxy-hemoCD1. The O2-Fe(II) bond is equivalent to the O2.--Fe(III) bond, which is attacked by the inorganic anions or the water molecule to produce met-hemoCD1 and a superoxide anion.

Calorimetry, Differential Scanning↗
PubMed2006

Ligand binding properties of two kinds of reconstituted myoglobins with iron porphycene having propionates: effect of beta-pyrrolic position of two propionate side chains in porphycene framework.

An iron porphycene containing two propionate side chains at the 12th and 17th beta-pyrrolic positions of the porphycene ring was synthesized and incorporated into sperm whale apomyoglobin in order to investigate the O(2) and CO binding properties of the reconstituted ferrous myoglobin. The protein showed a slower O(2) dissociation rate by 1/20, compared to the native myoglobin, whereas the CO dissociation rates were found to be almost the same. This tendency is similar to the result of a previous study on the reconstituted myoglobin with a porphycene having the propionates at the 13th and 16th beta-pyrrolic positions. However, the present myoglobin showed a faster O(2) dissociation than the previously studied myoglobin. This finding suggests that the position of the two propionates as well as the symmetry of the porphycene framework is an important factor for obtaining a stable oxygenated iron porphycene myoglobin.

Circular Dichroism↗
PubMed2005

Preparation and O2 binding study of myoglobin having a cobalt porphycene.

Sperm whale myoglobin, an oxygen-storage hemoprotein, was reconstituted with 2,7-diethyl-3,6,12,17-tetramethyl-13,16-bis(carboxyethyl)porphycenatocobalt(II) in order to investigate the reactivities of a cobalt porphycene in a protein matrix. Similar to the previously reported finding for the myoglobin with the iron porphycene, the reconstituted myoglobin with the cobalt porphycene was also found to have an O2 affinity 2 orders of magnitude greater than that of the myoglobin possessing cobalt protoporphyrin IX. The EPR spectra of the deoxy and oxy myoglobins having the cobalt porphycene at 77 K also have features similar to those of the myoglobin with cobalt protoporphyrin IX. These spectra suggest that the porphycene cobalt in the deoxy form is coordinated by one nitrogenous ligand postulated to be the imidazole ring of His93, and that the bond configuration of CoII-O2 is regarded as the CoIII-Omicron2*- species.

Cobalt↗
PubMed2005

Unusual ligand discrimination by a myoglobin reconstituted with a hydrophobic domain-linked heme.

New, reconstituted horse heart myoglobins possessing a hydrophobic domain at the terminal of the two heme propionate side chains were constructed. The O2 and CO bindings for the reconstituted deoxymyoglobins were examined in detail by laser flash photolysis and stopped-flow rapid mixing techniques. The artificially created domain worked as a barrier against exogenous ligand penetration into the heme pocket, whereas the bound O2 was stabilized in the reconstituted myoglobin as well as in the native one. In contrast, the CO dissociation rate for the reconstituted myoglobin increased by 20-fold compared to the native protein, suggesting that the incorporation of the hydrophobic domain onto the heme pocket perturbs the distal-site structure of the reconstituted myoglobin. As a result, the substantial ligand selectivity for the reconstituted myoglobin significantly increases in favor of O2 over CO with the M' value (= KCO/KO2) of 0.88, whereas, to the best of our knowledge, there is no myoglobin mutant in which the O2 affinity exceeds the CO one. The present work concludes that the O2 selectivity of myoglobin over CO is markedly improved by chemically modifying the heme propionates without any mutation of the amino acid residues in the distal site.

Animals↗
PubMed2005

Gene transfection into HeLa cells by vesicles containing cationic peptide lipid.

Lipid vesicles are potentially useful as microcapsules for drug and/or gene delivery. We developed cationic lipid vesicles consisting mainly of sorbitan monooleate (Span 80) and cationic peptide lipid (CPL), and evaluated the CPL vesicles as gene transfection vectors. The optimum CPL concentration for gene transfection into HeLa cells was found to be 20 wt % of total lipid, and such CPL vesicles did not exhibit significant cytotoxicity. Co-culture of Poly-L-lysine and plasmids prior to making CPL vesicle-plasmid complexes was effective. Lipofection using LipofectAMINE was suppressed in 10% serum-supplemented medium. The transfection efficiency of 20 wt % CPL vesicles, however, was not affected by serum in the medium when plasmids were treated with poly-L-lysine.

Blood↗
PubMed2004

Ligand binding properties of myoglobin reconstituted with iron porphycene: unusual O2 binding selectivity against CO binding.

Sperm whale myoglobin, an oxygen storage hemoprotein, was successfully reconstituted with the iron porphycene having two propionates, 2,7-diethyl-3,6,12,17-tetramethyl-13,16-bis(carboxyethyl)porphycenatoiron. The physicochemical properties and ligand bindings of the reconstituted myoglobin were investigated. The ferric reconstituted myoglobin shows the remarkable stability against acid denaturation and only a low-spin characteristic in its EPR spectrum. The Fe(III)/Fe(II) redox potential (-190 mV vs NHE) determined by the spectroelectrochemical measurements was much lower than that of the wild-type. These results can be attributed to the strong coordination of His93 to the porphycene iron, which is induced by the nature of the porphycene ring symmetry. The O2 affinity of the ferrous reconstituted myoglobin is 2600-fold higher than that of the wild-type, mainly due to the decrease in the O2 dissociation rate, whereas the CO affinity is not so significantly enhanced. As a result, the O2 affinity of the reconstituted myoglobin exceeds its CO affinity (M' = K(CO)/K(O2) < 1). The ligand binding studies on H64A mutants support the fact that the slow O2 dissociation of the reconstituted myoglobin is primarily caused by the stabilization of the Fe-O2 sigma-bonding. The IR spectra for the carbon monoxide (CO) complex of the reconstituted myoglobin suggest several structural and/or electrostatic conformations of the Fe-C-O bond, but this is not directly correlated with the CO dissociation rate. The high O2 affinity and the unique characteristics of the myoglobin with the iron porphycene indicate that reconstitution with a synthesized heme is a useful method not only to understand the physiological function of myoglobin but also to create a tailor-made function on the protein.

Animals↗
PubMed2004

Photochemical dechlorination of DDT catalyzed by a hydrophobic vitamin B12 and a photosensitizer under irradiation with visible light.

Dechlorination of 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) was catalyzed by a hydrophobic vitamin B(12), heptamethyl cobyrinate perchlorate, with a visible light irradiation system containing a [Ru(ii)(bpy)(3)]Cl(2) photosensitizer, and the hydrophobic vitamin B(12) showed high catalytic efficiency and stability during the reaction.

Catalysis↗
PubMed2004

Hydrophobic vitamin B12. Part 19: electroorganic reaction of DDT mediated by hydrophobic vitamin B12.

The controlled-potential electrolysis of 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) was carried out at -1.4 V vs. Ag-AgCl in the presence of a hydrophobic vitamin B12, heptamethyl cobyrinate perchlorate. DDT was dechlorinated to form 1,1-bis(4-chlorophenyl)-2,2-dichloroethane (DDD), 1,1-bis(4-chlorophenyl)-2,2-dichloroethylene (DDE), 1-chloro-2,2-bis(4-chlorophenyl)ethylene (DDMU) and 1,1,4,4-tetrakis(4-chlorophenyl)-2,3-dichloro-2-butene (TTDB)(E/Z), and quantitative recovery of the catalyst after the electrolysis was confirmed by electronic spectroscopy. A photo-sensitive intermediate having a cobalt-carbon bond formed during the electrolysis was characterized by electronic spectroscopy. A mechanism for the formation of various dechlorinated products was investigated by using deuterium solvents and various spectroscopic measurements such as UV-VIS and the EPR spin-trapping technique.

Catalysis↗
PubMed2004

Hybridization of modified-heme reconstitution and distal histidine mutation to functionalize sperm whale myoglobin.

To modulate the physiological function of a hemoprotein, most approaches have been demonstrated by site-directed mutagenesis. Replacement of the native heme with an artificial prosthetic group is another way to modify a hemoprotein. However, an alternate method, mutation or heme reconstitution, does not always demonstrate sufficient improvement compared with the native heme enzyme. In the present study, to convert a simple oxygen storage hemoprotein, myoglobin, into an active peroxidase, we applied both methods at the same time. The native heme of myoglobin was replaced with a chemically modified heme 2 having two aromatic rings at the heme-propionate termini. The constructed myoglobins were examined for 2-methoxyphenol (guaiacol) oxidation in the presence of H2O2. Compared with native myoglobin, rMb(H64D.2) showed a 430-fold higher kcat/Km value, which is significantly higher than that of cytochrome c peroxidase and only 3-fold less than that of horseradish peroxidase. In addition, myoglobin-catalyzed degradation of bisphenol A was examined by HPLC analysis. The rMb(H64D.2) showed drastic acceleration (>35-fold) of bisphenol A degradation compared with the native myoglobin. In this system, a highly oxidized heme reactive species is smoothly generated and a substrate is effectively bound in the heme pocket, while native myoglobin only reversibly binds dioxygen. The present results indicate that the combination of a modified-heme reconstitution and an amino acid mutation should offer interesting perspectives toward developing a useful biomolecule catalyst from a hemoprotein.

Animals↗
PubMed2003

Synthesis, characterization, and autoreduction of a highly electron-deficient porphycenatoiron(III) with trifluoromethyl substituents.

The synthesis of the first fluorine-containing iron porphycenes, 2,7,12,17-tetraethyl-3,6,13,16-tetrakis(trifluoromethyl)porphycenatoiron(III) chloride [FePc(EtioCF(3))]Cl and its micro-oxo dimer [FePc(EtioCF(3))](2)O and their characterizations are reported. The crystal structure of [FePc(EtioCF(3))](2)O displays a severe saddled distortion of the porphycene framework due to the steric and electronic effects of the CF(3) substituents. The oxidation and reduction potentials for the micro-oxo dimer are significantly more positive compared to those observed for the reference micro-oxo dimer of the iron porphycenes and porphyrins having no electron-withdrawing substituent. Moreover, the (1)H and (19)F NMR spectra of [FePc(EtioCF(3))](2)O demonstrated that the micro-oxo dimer is readily converted into the monomeric ferrous complex in pyridine-d(5) through autoreduction for 1 day, although the reduction of the reference iron porphycenes and porphyrins are not observed in pyridine. These results indicate that the trifluoromethylated iron porphycene is a highly electron-deficient complex with a pyrrolic macrocycle ligand.

Journal Article↗
PubMed2003

Synthesis, structure, and chemical property of the first fluorine-containing porphycene.

[structure: see text] A pyrrolic macrocycle, beta-tetrakis(trifluoromethyl)porphycene, is the first example of a fluorine-containing porphycene. Four electron-withdrawing CF(3) substituents provide a highly distorted structure and an attractive electron-deficient nature for the porphycene framework. From the electrochemical study, it is found that the LUMO energy level for the beta-trifluoromethylporphycene is 1.24 V more stabilized compared to that for etioporphyrin. Moreover, the deprotonation of the inner N[bond]H proton in the porphycene was observed upon the addition of DBU.

Journal Article↗
PubMed2003

N-confused porphyrin-bearing meso-perfluorophenyl groups: a potential agent that forms stable square-planar complexes with Cu(II) and Ag(III).

[reaction: see text] N-Confused porphyrin (NCP) bearing pentafluorophenyl groups at meso-positions, which were obtained from N-confused dipyrromethane in ca. 20% yield, can form Cu(II) complex as well as Ag(III), Ni(II), and Pd(II) complexes. The square-planar structures of all these metal complexes were elucidated by X-ray single-crystal analyses.

Journal Article↗
PubMed2003

Iron twin-coronet porphyrins as models of myoglobin and hemoglobin: amphibious electrostatic effects of overhanging hydroxyl groups for successful CO/O2 discrimination.

Inspired by the observation of polar interactions between CO and O(2) ligands and the peptide residues at the active site of hemoglobin and myoglobin, we synthesized two kinds of superstructured porphyrins: TCP-IM, which contains a linked imidazole ligand, and TCP-PY, which contains a linked pyridine ligand, and examined the thermodynamic, kinetic, and spectroscopic (UV/Vis, IR, NMR, and resonance Raman) properties of their CO and O(2) complexes. On both sides of each porphyrin plane, bulky binaphthyl bridges form hydrophobic cavities that are suitable for the binding of small molecules. In the proximal site, an imidazole or pyridine residue is covalently fixed and coordinates axially to the central iron atom. In the distal site, two naphtholic hydroxyl groups overhang toward the center above the heme. The CO affinities of TCPs are significantly lower than those of other heme models. In contrast, TCPs have moderate O(2) binding ability. Compared with reported model hemes, the binding selectivity of O(2) over CO in TCP-IM and TCP-PY complexes is greatly improved. The high O(2) selectivity of the TCPs is mainly attributable to a low CO affinity. The comparison of k(on)(CO) values of TCPs with those of unhindered hemes indicates the absence of steric hindrance to the intrinsically linear CO coordination to Fe(II) in TCP-IM and TCP-PY. The abnormally large k(off)(CO) values are responsible for the low CO affinities. In contrast, k(off)(O(2)) of TCP-PY is smaller than those of other pyridine-coordinated model hemes. For the CO adducts of TCPs, unusually low nu(Fe-CO) and unusually high nu(C-O) frequencies are observed. These results can be ascribed to decreased back-bonding from the iron atom to the bound CO. The lone pairs of the oxygen atoms of the hydroxyl groups prevent back-bonding by exertion of a strong negative electrostatic interaction. On the other hand, high nu(Fe-O(2)) frequencies are observed for the O(2) adducts of TCPs. In the resonance Raman (RR) spectrum of oxy-TCP-IM, we observed simultaneous enhancement of the Fe-O(2) and O-O stretching modes. Furthermore, direct evidence for hydrogen bonding between the hydroxyl groups and bound dioxygen was obtained by RR and IR spectroscopy. These spectroscopic data strongly suggest that O(2) and CO binding to TCPs is controlled mainly by the two different electrostatic effects exerted by the overhanging OH groups: destabilization of CO binding by decreasing back-bonding and stabilization of O(2) binding by hydrogen bonding.

Algorithms↗
PubMed2002

Polysaccharide-polynucleotide complexes VIII. Cation-induced complex formation between polyuridylic acid and schizophyllan.

Schizophyllan belongs to the beta-1,3-D-glucan family, and dissolves as a single chain in dimethyl sulfoxide (DMSO) and as a triple helix in water, respectively. It is already known that when we prepare a mixture of poly(C) and schizophyllan in DMSO and subsequently exchange the solvent to water, poly(C) and schizophyllan can form a complex. When we applied this procedure to the poly(U) system, we could not induce the complex formation between poly(U) and schizophyllan at all. However, we found that addition of some alkaline cations is necessary to induce the complexation between poly(U) and schizophyllan. The complex stability strongly depends on both the cation species and the salt concentration. The complexation is sensitively reflected in the CD spectrum. The magnitude of the spectral change is followed by the order; Rb(+) >> K(+) > Na(+) ? Cs(+). This cation order in the stability is confirmed by the fluorescence polarization measurements. (23)Na-NMR spectroscopy reveals that the product system is stabilized by addition of the cations, suggesting that the OH group in schizophyllan and the phosphate anion in poly(U) synergistically form a specific ligand system for the cations. To the best of our knowledge, such a cation-induced specific interaction between saccharides and polynucleotides has not been reported, and may provide a new clue to understand the biological role of beta-1,3-D-glucans.

Circular Dichroism↗