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Biomedical subjects

Satoshi Kaneko

Publications and source records attributed to Satoshi Kaneko.

At least 37 records · Page 2Linked to original sources
PubMed2005

Cloning and expression of the gene encoding Streptomyces coelicolor A3(2) alpha-galactosidase belonging to family 36.

The alpha-galactosidase gene of Streptomyces coelicolor A3(2) was cloned, expressed in Escherichia coli and characterized. It consisted of 1497 nucleotides encoding a protein of 499 amino acids with a predicted molecular weight of 57,385. The observed homology between the deduced amino acid sequences of the enzyme and alpha-galactosidase from Thermus thermophilus was over 40%. The alpha-galactosidase gene was assigned to family 36 of the glycosyl hydrolases. The enzyme purified from recombinant E. coli showed optimal activity at 40 degrees C and pH 7. The enzyme hydrolyzed p-nitrophenyl-alpha-D -galactopyroside, raffinose, stachyose but not melibiose and galactomanno-oligosaccharides, indicating that this enzyme recognizes not only the galactose moiety but also other substrates.

Amino Acid Sequence↗
PubMed2005

Trends in lung cancer mortality among young adults in Japan.

BACKGROUND: Trends in lung cancer mortality among young adults, which are important for projecting future trends, have not been explored previously in Japan. METHODS: Using data from the National Vital Statistics between 1958 and 2003, we compiled lung cancer mortality by sex and 5-year birth cohort among young adults aged 20-49. RESULTS: Mortality among those aged 20-29 has consistently decreased regardless of sex. There were birth cohort effects in mortality from lung cancer, although these were less evident among women than among men. Both men and women born in the 1930s had lower mortality rates, while those born after 1940 had higher lung cancer mortality rates. Mortality rates appear to be declining for male birth cohorts born after 1950 and female birth cohorts after 1960, although these trends may not be stable due to the small number of deaths in these cohorts. CONCLUSION: Lung cancer mortality trends appear to be decreasing among young adults. This might be associated with the lower mortality of birth cohorts after 1950 for men and the 1960s birth cohorts for women. Careful monitoring is needed to confirm continuation of these declining trends.

Adult↗
PubMed2005

Characterization of carbohydrate-binding cytochrome b562 from the white-rot fungus Phanerochaete chrysosporium.

cDNA encoding a hemoprotein similar to the cytochrome domain of extracellular flavocytochrome cellobiose dehydrogenase (CDH) was cloned from the white-rot fungus Phanerochaete chrysosporium. The deduced amino acid sequence implies that there is a two-domain structure consisting of an N-terminal cytochrome domain and a C-terminal family 1 carbohydrate-binding module (CBM1) but that the flavin-containing domain of CDH is not present. The gene transcripts were observed in cultures in cellulose medium but not in cultures in glucose medium, suggesting that there is regulation by carbon catabolite repression. The gene was successfully overexpressed in Pichia pastoris, and the recombinant protein was designated carbohydrate-binding cytochrome b562 (CBCyt. b562). The resonance Raman spectrum suggested that the heme of CBCyt. b562 is 6-coordinated in both the ferric and ferrous states. Moreover, the redox potential measured by cyclic voltammetry was similar to that of the cytochrome domain of CDH. These results suggest that the redox characteristics may be similar to those of the cytochrome domain of CDH, and so CBCyt. b562 may have an electron transfer function. In a binding study with various carbohydrates, CBCyt. b562 was adsorbed with high affinity on both cellulose and chitin. As far as we know, this is the first example of a CBM1 connected to a domain without apparent catalytic activity for carbohydrate; this CBM1 may play a role in localization of the redox protein on the surface of cellulose or on the fungal sheath in vivo.

Amino Acid Sequence↗
PubMed2005

A single amino acid substitution enhances the catalytic activity of family 11 xylanase at alkaline pH.

Random mutagenesis of the gene encoding family 11 xylanase was used to obtain alkalophilic mutants. The catalytic domain of the chimeric enzyme Stx15, which was constructed from Streptomyces lividans xylanase B and Thermobifida fusca xylanase A, was mutated using error-prone PCR and screened for halo formation on dye-linked xylan plates and activity toward soluble xylan. A positive mutant, M1011, was isolated, and it was found that mutation A49V was responsible for the alkalophilicity of the mutant. Mutation A49V increased the specific activity at pH 9.1 and the stability of mutant A49V was not significantly different from that of Stx15 at 60 degrees C. Both enzymes retained more than 90% of their relative activity from pH 4.7 to 9.1 after 1 h of incubation at 60 degrees C. Analysis of the kinetic parameters at various pH values showed that the A49V mutation reduced the Km in the alkaline pH range, resulting in the higher specific activity of the A49V mutant enzyme.

Amino Acid Sequence↗
PubMed2005

A framework for cancer surveillance in Japan.

The World Health Organization (WHO) has recommended that countries develop national cancer control programs in order to reduce the number of deaths due to preventable cancers. The national cancer control program should be comprehensive and systematic with evidence-based priority-setting and the efficient use of limited resources. In order to provide evidence-based information, cancer surveillance systems must be established with registration as a focus. Cancer registration monitors the incidence, mortality, survival, and prevalence of cancers. In Japan, however, cancer registration systems have not been either well developed or standardized until recently. In 2003, the Ministry of Health, Labour and Welfare of Japan launched the Third Term Comprehensive 10-Year Strategy Program for Cancer Control, which gave grants to several projects to enhance the dissemination and standardization of cancer registries. However, the establishment of a cancer registration system is merely the first step in the process to provide a comprehensive surveillance system that leads to a national cancer control program, as proposed by the WHO. To provide the best cancer care services equitably in Japan, cancer surveillance systems should be established without delay.

Humans↗
PubMed2004

Aurora-A abrogation of p53 DNA binding and transactivation activity by phosphorylation of serine 215.

The tumor suppressor p53 is important in the decision to either arrest cell cycle progression or induce apoptosis in response to a variety of stimuli. p53 posttranslational modifications and association with other proteins have been implicated in the regulation of its stability and transactivation activity. Here we show that p53 is phosphorylated by the mitotic kinase Aurora-A at serine 215. Unlike most identified phosphorylation sites of p53 that positively associate with p53 function (Brooks, C. L., and Gu, W. (2003) Curr. Opin. Cell Biol. 15, 164-171), the phosphorylation of p53 by Aurora-A at Ser-215 abrogates p53 DNA binding and transactivation activity. Downstream target genes of p53, such as p21Cip/WAF1 and PTEN, were inhibited by Aurora-A in a Ser-215 phosphorylation-dependent manner (i.e. phosphomimic p53-S215D lost and non-phosphorylatable p53-S215A retained normal p53 function). As a result, Aurora-A overrides the apoptosis and cell cycle arrest induced by cisplatin and gamma-irradiation, respectively. However, the effect of Aurora-A on p53 DNA binding and transactivation activity was not affected by phosphorylation of Ser-315, a recently identified Aurora-A phosphorylation site of p53 (Katayama, H., Sasai, K., Kawai, H., Yuan, Z. M., Bondaruk, J., Suzuki, F., Fujii, S., Arlinghaus, R. B., Czerniak, B. A., and Sen, S. (2004) Nat. Genet. 36, 55-62). Our data indicate that phosphorylation of p53 at Ser-215 by Aurora-A is a major mechanism to inactivate p53 and can provide a molecular insight for Aurora-A function.

Amino Acid Sequence↗
PubMed2004

Crystal structure of aspartic proteinase from Irpex lacteus in complex with inhibitor pepstatin.

The crystal structure of Irpex lacteus aspartic proteinase (ILAP) in complex with pepstatin (a six amino acid residue peptide-like inhibitor) was determined at 1.3A resolution. ILAP is a pepsin-like enzyme, widely distributed in nature, with high milk-clotting activity relative to proteolytic activity. The overall structure was in good topological agreement with pepsin and other aspartic proteases. The structure and interaction pattern around the catalytic site were conserved, in agreement with the other aspartic proteinase/inhibitor complex structures reported previously. The high-resolution data also supported the transition state model, as proposed previously for the catalytic mechanism of aspartic proteinase. Unlike the other aspartic proteinases, ILAP was found to require hydrophobic residues either in the P(1) or P(1') site, and also in the P(4) and/or P(3) site(s) for secondary interactions. The inhibitor complex structure also revealed the substrate binding mechanism of ILAP at the P(3) and P(4) site of the substrate, where the inserted loop built up the unique hydrophobic pocket at the P(4) site.

Amino Acid Sequence↗
PubMed2004

UDP-sugar pyrophosphorylase with broad substrate specificity toward various monosaccharide 1-phosphates from pea sprouts.

UDP-sugars, activated forms of monosaccharides, are synthesized through de novo and salvage pathways and serve as substrates for the synthesis of polysaccharides, glycolipids, and glycoproteins in higher plants. A UDP-sugar pyrophosphorylase, designated PsUSP, was purified about 1,200-fold from pea (Pisum sativum L.) sprouts by conventional chromatography. The apparent molecular mass of the purified PsUSP was 67,000 Da. The enzyme catalyzed the formation of UDP-Glc, UDP-Gal, UDP-glucuronic acid, UDP-l-arabinose, and UDP-xylose from respective monosaccharide 1-phosphates in the presence of UTP as a co-substrate, indicating that the enzyme has broad substrate specificity toward monosaccharide 1-phosphates. Maximum activity of the enzyme occurred at pH 6.5-7.5, and at 45 degrees C in the presence of 2 mm Mg(2+). The apparent K(m) values for Glc 1-phosphate and l-arabinose 1-phosphate were 0.34 and 0.96 mm, respectively. PsUSP cDNA was cloned by reverse transcriptase-PCR. PsUSP appears to encode a protein with a molecular mass of 66,040 Da (600 amino acids) and possesses a uridine-binding site, which has also been found in a human UDP-N-acetylhexosamine pyrophosphorylase. Phylogenetic analysis revealed that PsUSP can be categorized in a group together with homologues from Arabidopsis and rice, which is distinct from the UDP-Glc and UDP-N-acetylhexosamine pyrophosphorylase groups. Recombinant PsUSP expressed in Escherichia coli catalyzed the formation of UDP-sugars from monosaccharide 1-phosphates and UTP with efficiency similar to that of the native enzyme. These results indicate that the enzyme is a novel type of UDP-sugar pyrophosphorylase, which catalyzes the formation of various UDP-sugars at the end of salvage pathways in higher plants.

Amino Acid Sequence↗
PubMed2004

Rational affinity purification of native Streptomyces family 10 xylanase.

Xylanase SoXyn10A from Streptomyces olivaceoviridis E-86 comprises a family 10 catalytic module linked to a family 13 carbohydrate-binding module (SoCBM13). The SoCBM13 has a beta-trefoil structure, with binding sites in each subdomain (alpha, beta and gamma). Subdomain alpha, but not subdomains beta and gamma, binds tightly to lactose. It was, therefore, thought that immobilized lactose could be used for the affinity purification of SoXyn10A. Lactosyl-Sepharose was prepared and tested as an affinity matrix. SoXyn10A produced from the cloned xyn10A gene by Escherichia coli, and native SoXyn10A in culture supernatants from S. olivaceoviridis, were purified to homogeneity in a single step by affinity chromatography using this matrix. This simple purification of SoXyn10A makes the enzyme an attractive candidate for applications requiring xylanase. The CBM also has the potential for use as an affinity tag for the purification of other proteins.

Blotting, Western↗
PubMed2004

Structure and function of a family 10 beta-xylanase chimera of Streptomyces olivaceoviridis E-86 FXYN and Cellulomonas fimi Cex.

The catalytic domain of xylanases belonging to glycoside hydrolase family 10 (GH10) can be divided into 22 modules (M1 to M22; Sato, Y., Niimura, Y., Yura, K., and Go, M. (1999) Gene (Amst.) 238, 93-101). Inspection of the crystal structure of a GH10 xylanase from Streptomyces olivaceoviridis E-86 (SoXyn10A) revealed that the catalytic domain of GH10 xylanases can be dissected into two parts, an N-terminal larger region and C-terminal smaller region, by the substrate binding cleft, corresponding to the module border between M14 and M15. It has been suggested that the topology of the substrate binding clefts of GH10 xylanases are not conserved (Charnock, S. J., Spurway, T. D., Xie, H., Beylot, M. H., Virden, R., Warren, R. A. J., Hazlewood, G. P., and Gilbert, H. J. (1998) J. Biol. Chem. 273, 32187-32199). To facilitate a greater understanding of the structure-function relationship of the substrate binding cleft of GH10 xylanases, a chimeric xylanase between SoXyn10A and Xyn10A from Cellulomonas fimi (CfXyn10A) was constructed, and the topology of the hybrid substrate binding cleft established. At the three-dimensional level, SoXyn10A and CfXyn10A appear to possess 5 subsites, with the amino acid residues comprising subsites -3 to +1 being well conserved, although the +2 subsites are quite different. Biochemical analyses of the chimeric enzyme along with SoXyn10A and CfXyn10A indicated that differences in the structure of subsite +2 influence bond cleavage frequencies and the catalytic efficiency of xylooligosaccharide hydrolysis. The hybrid enzyme constructed in this study displays fascinating biochemistry, with an interesting combination of properties from the parent enzymes, resulting in a low production of xylose.

Catalytic Domain↗
PubMed2004

Trends in reported incidences of gastric cancer by tumour location, from 1975 to 1989 in Japan.

BACKGROUND: This study was performed to estimate the incidence of gastric cancer by tumour location and to clarify whether the relative and absolute rates of gastric cancer in Japan changed between 1975 and 1989. METHODS: The stomach was anatomically divided into the upper, middle, and lower thirds. Age- and sex-specific incidences by tumour location were estimated by multiplying the age- and sex-specific national incidences of gastric cancer by the corresponding proportions of tumour location. We studied 171 721 cases of gastric cancer from the Gastric Cancer Registry of Japan. RESULTS: Over 15 years, the proportion of tumours in the upper third of the stomach increased in men but did not change much in women. The proportion of tumours in the middle third of the stomach increased among both men and women while the proportion of tumours in the lower third of the stomach decreased among both men and women. The incidence of tumours in the upper third of the stomach showed an increasing trend among elderly men and women but not among young ones. The incidence of tumours in the lower third of the stomach decreased significantly among men and women of most age groups. CONCLUSIONS: The present study added evidence of disparate trends in the incidence of gastric cancer by tumour location. The separate epidemiological features may indicate different aetiologies as well as changes in the degree of influence of these aetiologies.

Adenocarcinoma↗
PubMed2004

Molecular cloning and expression in Escherichia coli of a Trichoderma viride endo-beta-(1-->6)-galactanase gene.

The nucleotide sequence depicted in Figure 1 has been submitted to the DDBJ nucleotide sequence database under the accession no. AB104898. A gene encoding endo-beta-(1-->6)-galactanase from Trichoderma viride was cloned by reverse transcriptase-PCR and expressed in Escherichia coli. The gene contained an open reading frame consisting of 1437 bp (479 amino acids). The deduced amino acid sequence of the protein showed little similarity with other known glycoside hydrolases. A signal sequence (20 amino acids) was found at the N-terminal region of the protein and the molecular mass of the mature form was calculated to be 50.488 kDa. The gene product expressed in E. coli as a recombinant protein fused with thioredoxin and His(6) tags had almost the same substrate specificity and mode of action as native enzyme purified from a commercial cellulase preparation of T. viride, i.e. recombinant enzyme endo-hydrolysed beta-(1-->6)-galacto-oligomers with a DP (degree of polymerization) higher than 3, and it could also hydrolyse alpha-L-arabinofuranosidase-treated arabinogalactan protein from radish. It produced beta-(1-->6)-galacto-oligomers ranging from DP 2 to at least 8 at the initial hydrolysis stage and galactose and beta-(1-->6)-galactobiose as the major products at the final reaction stage. These results indicate that the cloned gene encodes an endo-beta-(1-->6)-galactanase. As far as we know, this is the first time an endo-beta-(1-->6)-galactanase has been cloned.

Amino Acid Sequence↗
PubMed2004

Module shuffling.

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Amino Acid Sequence↗