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N Sone

Publications and source records attributed to N Sone.

At least 19 recordsLinked to original sources
PubMed1991

The cytochrome C oxidase genes in blue-green algae and characteristics of the deduced protein sequence for subunit II of the thermophilic cyanobacterium Synechococcus vulcanus.

Blue-green algae (cyanobacteria) contain both primitive photosynthetic and respiratory systems in their membranes. The controversial genes coding for an alpha alpha 3-type cytochrome oxidase in cyanobacteria were examined. The DNA probe coding for the most conserved part of subunit I hybridized with DNA fragments from four cyanobacterial species. We have cloned the genes coding for subunits I and II from the genomic library of the thermophilic cyanobacterium Synechococcus vulcanus and determined the nucleotide sequence of the subunit II gene. The deduced protein sequence (327 amino acid residues) indicates that there are two hydrophobic segments near the N-terminus and a hydrophilic intermembrane domain containing ligands for CuA (the ESR-active Copper) similar to other subunit IIs. The S. vulcanus subunit II does not contain the cytochrome c moiety that is present in bacilli and thermophiles.

Amino Acid Sequence↗
PubMed1991

Haem O2 can replace haem A in the active site of cytochrome c oxidase from thermophilic bacterium PS3.

Thermophilic bacterium PS3 cultured under slightly air-limited conditions showed a mitochondrion-like cytochrome pattern similar to that in vigorously aerated cells, but an o-type cytochrome replaced cytochrome a3 as the CO-binding centre. Cytochrome cao-type oxidase was purified from the cell membranes by almost the same procedure as used for cytochrome caa3. The turnover number of cytochrome cao was higher than that of cytochrome caa3, but the Km's of the two enzymes for cytochrome c and O2 were almost the same. Gel electrophoresis in the presence of sodium dodecyl sulfate gave bands of four subunits at the identical positions both for cytochrome cao and cytochrome caa3. Cytochrome cao contained a novel kind of haem in addition to haems C and A. This novel haem is likely to be haem O, very recently found as the chromophore of the cytochrome bo complex in Escherichia coli. These data suggest that cytochrome cao is an alternative form of cytochrome c oxidase (cytochrome caa3), in which the cytochrome a3 centre of the enzyme is replaced with cytochrome o.

Binding Sites↗
PubMed1991

Effects of aeration during growth of Bacillus stearothermophilus on proton pumping activity and change of terminal oxidases.

The effects of aeration during bacterial growth on the proton translocating activity of the respiratory chain of B. stearothermophilus ATCC 8005, which is stable enough for measurement of the H+/O ratio by an oxygen pulse method, were examined. For endogenous and ascorbate-N,N,N',N'-tetramethyl p-phenylene diamine (TMPD) respiration, H+/O ratios of around 6 and 2 were obtained using resting cells grown under highly aerated conditions. The values were about 4 and 0 when cells were grown under limited-air conditions. Spectrophotometric and enzyme kinetical analyses revealed that both cytochrome caa3 and pigment-432 (cytochrome cao) were acting as terminal oxidases, while cytochrome b-558 (corresponding to the "cytochrome o-type oxidase" of the thermophilic bacterium PS3 in the previous paper [Sone, N., Kutoh, E., & Sato, K. (1990) J. Biochem. 107, 597-602]) was mainly serving in the cells grown under limited-air conditions. Measurement of the pH change upon ferrocytochrome c pulse with proteoliposomes reconstituted from the membrane extract of vigorously aerated cells and that of limited-air cells suggested that both cytochrome caa3, and pigment-432 (cytochrome cao) pump protons, while cytochrome b-558 does not.

Air↗
PubMed1991

Synergistic action in platelet activation induced by an antiplatelet autoantibody in ITP.

We detected an autoantibody which activated normal platelets in a patient with immune thrombocytopenic purpura and investigated the mechanism by which this autoantibody mediated platelet activation. The patient's IgG induced platelet aggregation and ATP secretion in normal platelet-rich plasma (PRP). IgG-induced aggregation was inhibited by aspirin (ASA), apyrase, a protein kinase C (PKC) inhibitor and two anti-platelet glycoprotein (GP) IIb/IIIa monoclonal antibodies. The increase of aequorin-detected intraplatelet Ca2+ induced by the patient's IgG was extremely slight. Phosphorylation of a 40 kDa protein was induced by the patient's IgG without any obvious phosphorylation of a 20 kDa protein, and was inhibited by a PKC inhibitor but not by ASA. With ASA-treated normal PRP, the patient's IgG failed to induce aggregation itself, but enhanced ADP- or STA2-induced aggregation. Western blotting and immunoprecipitation experiments showed that the patient's IgG reacted to a protein of 36 kDa. These results suggest that the platelet activation induced by this autoantibody depended on both the selective activation of PKC and the slight Ca2+ mobilization induced by thromboxane A2 synthesis, while the aggregation depended on secretion induced by the synergistic action of the above two mechanisms and was mediated through GP IIb/IIIa.

Adenosine Triphosphate↗
PubMed1991

Influences of antiplatelet autoantibodies on platelet function in immune thrombocytopenic purpura.

We investigated the characteristics of the antiplatelet autoantibodies in 60 patients with ITP. Using flow cytometry, the binding of monoclonal antibodies to the platelet glycoprotein (GP) IIb/IIIa complex and to GPIb was examined in these patients. The extent of binding was decreased in 15 patients (anti-GPIIb/IIIa in 12 patients and both anti-GPIIb/IIIa and anti-GPIb in 3 patients). Western blotting revealed that 10 of these 15 patients had either anti-GPIIb or anti-GPIIIa and 2 had anti-GPIb autoantibodies, ADP-induced aggregation of normal platelets was inhibited by autoantibodies in 12 of 60 patients, and 11 of these had anti-GPIIb/IIIa antibodies. Ristocetin-induced aggregation was inhibited in 4 of these patients, and 2 with prominent inhibition had anti-GPIb antibodies. There was a significant relationship between platelet-associated IgG value and ATP secretion. These results suggest that some antiplatelet autoantibodies can affect platelet function and thus have an influence on the pathophysiology of ITP.

Adenosine Diphosphate↗
PubMed1990

Monomer-dimer structure of cytochrome-c oxidase and cytochrome bc1 complex from the thermophilic bacterium PS3.

Molecular weights of three membrane proteins have been measured in the presence of 0.1% octaethylene glycol n-dodecyl ether (C12E8) by the measuring system in which a membrane protein eluted from a gel chromatography column is monitored sequentially for ultraviolet absorption, light scattering and refractive index. The relative molecular mass (Mr) and amount of bound detergent per protein (delta) can be calculated from these data, if instrumental constants are measured using a set of appropriate water-soluble proteins which does not bind nonionic surfactants. The molecular masses of cytochrome c oxidase and cytochrome bc1 complex from the thermophilic bacterium PS3 were determined to be 127 kDa and 185 kDa, respectively, indicating that the oxidase is monomeric, while the bc1 complex dimeric in the presence of C12E8. The larger apparent molecular mass of about 310 kDa of the PS3 oxidase obtained from the retention time of the gel chromatography (Sone, N., Sekimachi, M. and Kutoh, E. (1987) J. Biol. Chem. 262, 15386-15391) turned out to be due to a high binding ability with the detergent (delta = 1.25 g/g) of this very hydrophobic protein. Analyses of bovine heart cytochrome oxidase, on which monomer/dimer properties have been reported, showed that the enzyme is mainly dimeric (Mr = 374,000), while a small portion is monomeric (Mr = 191,000). Mild alkaline treatment of this enzyme caused monomerization of the enzyme with accompanying aggregate formation. These results, thus, show that this method is suitable to analyze monomer/dimer conversion of membrane protein as well as to estimate structure of membrane proteins.

Animals↗
PubMed1990

The alpha 1 beta 1 heterodimer of ATP synthase.

The alpha 3 beta 3 hexamer was reconstituted from the alpha and beta subunits of TF1 portion of ATP synthase of thermophilic bacterium (Kagawa et al. (1989) FEBS Lett. 249, 67). The alpha 1 beta 1 heterodimer of ATP synthase was isolated by high performance liquid chromatography (HPLC) of the alpha 3 beta 3 hexamer in the presence of AT(D)P-Mg. On polyacrylamide gel electrophoresis, both bands corresponding to the dimer and hexamer showed ATPase activity. The alpha 1 beta 1 dimer was dissociated into the equal amounts of the alpha and beta monomers by sodium dodecyl sulfate. The alpha and beta monomers were practically inactive. The alpha 2 and beta 2 homodimers were not detected by electrophoresis and HPLC.

Bacteria↗
PubMed1990

Cytochrome oxidase from thermophilic bacterium PS3 contains a fourth protein subunit.

Monoclonal antibodies prepared against subunits II and IV of beef heart cytochrome oxidase were found to cross-react with thermophilic bacterial PS3 oxidase. Each individual antibody affects the enzymatic activity. "Western" blot analyses showed that subunit II antibodies of beef heart recognized subunit II of PS3 and subunit IV antibody likewise recognized a fourth protein subunit on slab gels. This fourth subunit previously thought to be a contaminant or a degradation product has a molecular weight of about 10,500 on SDS-gels, and appears to exist in stoichiometric amount. We have extracted this subunit from slab gels and compared its amino acid composition with that of subunit III.

Amino Acids↗
PubMed1990

A fourth subunit is present in cytochrome c oxidase from the thermophilic bacterium PS3.

A new putative subunit was found in cytochrome c oxidase (aa3-type) of the thermophilic bacterium PS3. The N-terminal amino acid sequence of this approximately 12 kDa protein coincides with the deduced sequence of an open reading frame found downstream from the gene encoding subunit I of the PS3 cytochrome oxidase [(1988) J. Biochem. 103, 606-610]. This small hydrophobic protein, composed of 109 amino acid residues after the initial methionine residue has been processed, shows homology with the subunit IV (cyoD product) of cytochrome bo-type quinol oxidase of Escherichia coli.

Amino Acid Sequence↗
PubMed1990

A cytochrome o-type oxidase of the thermophilic bacterium PS3 grown under air-limited conditions.

A cytochrome o-type oxidase from the thermophilic bacterium PS3 grown under air-limited conditions was purified by ion-exchange chromatography in the presence of a non-ionic detergent. The enzyme was composed of three subunits (60, 30, and 16 kDa) and seemed to contain two molecules of heme b as prosthetic groups. It contained no detectable copper. The reduced enzyme showed absorption bands at 426 and 558.5 nm, and a characteristic spectral change upon binding CO. It oxidized several cytochromes c and artificial dyes such as N,N,N',N'-tetramethyl-p-phenylenediamine and phenazonium methosulfate at appreciable rates. Its Km for O2 was low (0.09 microM). It was capable of transmembrane electron transfer, because when reconstituted into liposomes, it generated a membrane potential upon oxidation without pumping protons.

Atmosphere Exposure Chambers↗
PubMed1990

Nucleotide sequence of the gene coding for four subunits of cytochrome c oxidase from the thermophilic bacterium PS3.

The gene coding for four subunits of cytochrome aa3-type oxidase was isolated from a genomic DNA library of the thermophilic bacterium PS3 and sequenced. The N-terminus of each subunit was also sequenced to verify the initiation site of the reading frame. The deduced amino acid sequences contained 615 amino acid residues for subunit I (CO1/caaB product), 333 residues for subunit II (CO2/caaA product), 207 residues for subunit III (CO3/caaC product), and 109 residues for subunit IV (CO4/caaD product) after processing. Re-examination of the sequencing of caa revealed a longer open reading frame for CO1, which contains 14 transmembrane segments instead of 12 [Sone et al. (1988) J. Biochem. 103, 606-610], although the main portions of the sequences constituting cytochrome a (FeA), cytochrome a3 (FeB), and CuB are correct. PS3 CO2 has an additional sequence for cytochrome c after the CuA binding protein portion with 2 transmembrane segments, which is homologous to the mitochondrial counterpart. PS3 CO3 has DCCD-binding glutamyl residues but contains only 5 transmembrane segments, unlike the mitochondrial counterpart, which has 7 segments. The subunits of PS3 cytochrome oxidase (aa3-type) show clear similarity in amino acid sequences with those of cytochrome bo-type oxidase from Escherichia coli as well, in spite of the difference of hemes. PS3 CO3 and CO4 are much more similar to E. coli CO3 and CO4 than to mitochondrial CO3 and CO4, respectively.

Amino Acid Sequence↗
PubMed1990

Inhibition of ATP synthesis by 1-methyl-4-phenylpyridinium ion (MPP+) in mouse brain in vitro and in vivo.

The effects of the MPP+ ion on ATP synthesis were studied using mouse brains in vitro and in vivo. Oxidation of glutamate + malate in mitochondria estimated by polarography was significantly inhibited by MPP+, and synthesis of ATP was inhibited to approximately one-third of that of control by 0.05 mM of MPP+. Oxidation of alpha-glycerophosphate and succinate was not inhibited, and ATP was synthesized normally. In cerebral mitochondria of mice treated with 40 mg/kg of MPTP, oxidation of glutamate, pyruvate, and malate was also significantly inhibited, but ATP was synthesized in normal amounts. This inhibition was prevented by pretreatment of mice with pargyline. Our observation would give further support for the mitochondria hypothesis of the mechanism of neuronal degeneration in MPTP-induced parkinsonism.

1-Methyl-4-phenylpyridinium↗
PubMed1990

[Analysis of adhesive proteins on the surface membrane of platelet in malignant neoplasm].

Flow cytometry was used to detect fibrinogen (platelet associated fibrinogen: PAFbg) and fibronectin (PAFn) on the surface membrane of platelets in leukemia (9 cases), lung cancer (15 cases) and hepatoma (8 cases) patients (by one color analysis method), and simultaneously to investigate the binding of monoclonal anti-glycoprotein (GP) IIb/IIIa and anti-GP Ib antibodies (by two color analysis). All patient groups showed higher Fbg values than the normal control group, but no differences were found between patient groups. The values of Fbg and Fn showed a correlation, but the pattern of binding did not show a regular tendency in any patient group. There also was no significant correlation between Fbg values and the positive percentage of monoclonal anti-GPIIb/IIIa and anti-GPIb antibodies, and the binding of Fbg did not inhibit that of monoclonal antibody. The results suggest the following. 1. There are no differences in platelet activation in leukemia, lung cancer and hepatoma patients, and the degree of platelet activation is decided by the degree and the kind of stimulation. 2. The increase of both PAFbg and PAFn prove to the existence of activated platelet.

Blood Platelets↗
PubMed1989

A novel a-type terminal oxidase from Sulfolobus acidocaldarius with cytochrome c oxidase activity.

Cytochrome C oxidase was solubilized with a nonionic detergent n-decanoyl-N-methyl glucamide from the membranes of Sulfolobus acidocaldarius, a thermoacidophilic archaebacterium, and was purified. The enzyme oxidized horse heart cytochrome C with a Vmax of 63 mumols/min/mg at 50 degrees C. The activity was sensitive to cyanide. The enzyme also catalyzed oxygen uptake detergent on N, N, N', N'-tetramethyl p-phenylene diamine. An apparent molecular mass was estimated to be 150 kDa. The enzyme is composed of three subunits of 37, 23 and 14 kDa. Spectral characteristics were similar to typical bacterial aa3 except for the presence of a novel 583 nm peak observed in reduced minus oxidized difference spectrum.

Archaea↗
PubMed1989

Cytochrome c-551 from the thermophilic bacterium PS3 grown under air-limited conditions.

A small-sized c-type cytochrome, designated cytochrome c-551, was prepared from membrane fraction of the thermophilic bacterium PS3 grown under air-limited conditions by extraction with cholate, precipitation with polyethylene glycol, and successive chromatographies with DEAE-cellulose and Sephacryl S-200 in the presence of a detergent. The purified sample contained approximately 1 mol of heme c per 10,000 g protein; it showed absorption bands at 551, 522 and 416 nm upon reduction, and a Soret peak at 409 nm upon oxidation. This cytochrome showed a single band of 10 kDa on polyacrylamide gel electrophoresis with sodium dodecyl sulfate. The isoelectric point of this cytochrome c-551 was pH 4.0. Cytochrome c-551 was suggested to play an important role in the respiratory chain with a terminal oxidase cytochrome o, which is produced under air-limited conditions, since cytochrome c-551 could mediate electron transfer between cytochrome bc1(b6f) complex and cytochrome o, showing quinol oxidase activity.

Bacterial Proteins↗
PubMed1989

[Analysis of platelet surface conformation in thrombin-induced aggregation].

We used flow cytometry to investigate the change of platelet membrane glycoproteins (GPIb and GP IIb/IIIa) and the distributions of fibrinogen (Fbg), thrombospondin (TSP) and fibronectin (Fn) on the surface of thrombin-stimulated platelets. The binding of a monoclonal antibody directed at the von Willebrand factor binding site on GPIb decreased in thrombin-stimulated platelets. This antibody caused a reactive delay in thrombin-induced aggregation, but had little influence on aggregability. Slight thrombin-induced aggregation was observed even after blocking the binding of Fbg to GP II b/IIIa. The new expression of GP II b/IIIa was detected on the surface of thrombin-stimulated platelets, whereas there was little increase of Fbg dependent on this GP II b/IIIa. An increase of TSP after thrombin stimulation was observed on the surface of platelets of healthy controls and patients with Glanzmann's thrombasthenia (Type I). The level of on platelet surface was slightly increased by thrombin stimulation. The mechanism involved in thrombin-induced aggregation appears to differ from that in ADP-induced aggregation.

Adult↗