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K Takiguchi

Publications and source records attributed to K Takiguchi.

34 records · Page 2Linked to original sources
PubMed1995

Diverse incidences of individual oligopeptides (dipeptidic to hexapeptidic) in proteins of human, bakers' yeast, and Escherichia coli origin registered in the Swiss-Prot data base.

Oligopeptidic permutations of the 20 amino acid residues give rise to proteins of diverse functions. Our long-term goal is to produce a lexicon of oligopeptides, classifying them into at least five categories: (i) ubiquitous, (ii) function specific, (iii) group specific, (iv) species specific, and (v) nonexistent. To begin with, we report on the varying frequencies of individual oligopeptides (dipeptidic to hexapeptidic in length) found among 2862 human proteins, 1942 Saccharomyces cerevisiae proteins, and 2672 Escherichia coli proteins registered in the Swiss-Prot data base (version 29.0, released in June 1994). At all lengths (dipeptides to hexapeptides), homooligopeptides were very prominent among the most frequently occurring varieties in proteins of human and bakers' yeast origins. However, this was not the case with E. coli. While all of the expected 20(3) varieties of tripeptides were found among human proteins, three tripeptides (Cys-Cys-Trp, Trp-Trp-Cys, and Trp-Trp-His) were missing from the bakers' yeast proteins. Three tripeptides (Cys-Ile-Trp, Cys-Met-Tyr, and Cys-Trp-Trp) were also absent from E. coli proteins. Inasmuch as the Swiss-Prot data base already contained 67% of the expected total of 4000 E. coli proteins, it is virtually certain that 96,000 varieties of hexapeptides containing at least one or another of the three missing tripeptides noted above shall be nonexistent in E. coli. Furthermore, the observation of missing tripeptides in the bakers' yeast proteins suggests that nonexistent hexapeptides shall be highly phylum specific. Because of the sample size, only a small fraction of the 20(6) varieties of hexapeptides were expected to be encountered in the present survey. Indeed, only 1.2-1.5% of the possible hexapeptides were found, and the average copy number of observed hexapeptides varied between 1.06 and 1.25. Nevertheless, 33 varieties of hexapeptides occurred in 102-169 copies among human proteins. Furthermore, 15 of the 33 varieties contained such rarely used residues as Tyr, His, Cys, and Trp.

Amino Acid Sequence↗
PubMed1995

Characterization of the COOH terminus of non-muscle caldesmon mutants lacking mitosis-specific phosphorylation sites.

Phosphorylation of rat non-muscle caldesmon by cdc2 kinase causes reduction in most of caldesmon's properties, including caldesmon's binding to actin, myosin, and calmodulin, as well as its inhibition of actomyosin ATPase. We have generated and characterized the COOH terminus of caldesmon mutants lacking mitosis-specific phosphorylation sites, because the COOH-terminal half of caldesmon contains all 7 putative Ser or Thr sites for cdc2 kinase. Codons for the 7 putative Ser or Thr residues have been mutated to Ala, and resultant mutants were bacterially expressed. Analyses of the phosphopeptide maps of these mutants have identified 6 sites, including Ser-249, Ser-462, Thr-468, Ser-491, Ser-497, and Ser-527 as the mitosis-specific phosphorylation sites, whereas the phosphorylation of the remaining site, Thr-377, is not detected by this assay method. Actin binding experiments have suggested that 5 sites including Ser-249, Ser-462, Thr-468, Ser-491, and Ser-497 are important for the phosphorylation-dependent reduction in actin binding. Characterization of a mutant lacking all 7 Ser or Thr sites (7-fold mutant) has revealed that 7-fold mutation eliminates all phosphorylation sites by cdc2 kinase. While the in vitro properties of the 7-fold mutant, including actin, myosin, and calmodulin binding and inhibition of actomyosin ATPase, are very similar to those of nonmutated protein, such properties are not affected by the treatment with cdc2 kinase in contrast to nonmutated protein. This mutant should thus be useful to explore the functions of the mitosis-specific phosphorylation of caldesmon.

Amino Acid Sequence↗
PubMed1993

A deductive database system PACADE for analyzing 3-D and secondary structures of protein.

We have developed a deductive database system PACADE for analyzing 3-D and secondary structures of protein. The PACADE system consists of a relational database created from Protein Data Bank and a deductive engine DEE based on logic programming. It has the following features: (1) The system has an inference mechanism. This means by which users can easily write and check biological hypotheses using logical and declarative rules instead of procedural programs. (2) The relational database of the PACADE system stores data on both 3-D and secondary structures of protein. The integration of this two level structure makes feasible an abstract representation of the protein structure. We describe herein the design, functions, and implementation of this PACADE system.

Computer Graphics↗
PubMed1992

Protective effect of serum antibody on respiratory infection of influenza C virus in rats.

The effects of serum antibody on the replication of influenza C virus in the nose and lung were evaluated in rats challenged with the virus by the intranasal and endotracheal routes, respectively. Convalescent rat serum administered intraperitoneally prior to infection suppressed virus replication significantly in both the nasal and pulmonary tissues. Resistance achieved was however much greater in the lung than in the nose. Rats with a serum neutralizing antibody titer of 1:800 showed almost complete resistance to pulmonary virus infection, and virus yield from the lung was reduced 10- to 100-fold in animals with the antibody titer of 1:80-160 or less. In contrast, significant decrease in virus shedding from the nose was observed only in animals with a serum antibody titer of 1:800 or greater. The effect of adoptive transfer of monoclonal antibodies (MAbs) to haemagglutinin-esterase (HE) glycoprotein and matrix (M) protein on pulmonary virus replication was also examined. Anti-HE MAbs with neutralization activity prevented virus shedding from the lung almost completely whereas non-neutralizing anti-HE MAb and anti-M Mab showed no inhibitory effect.

Animals↗
PubMed1991

Heavy meromyosin induces sliding movements between antiparallel actin filaments.

Suzuki et al. [Biochemistry 28, 6513-6518 (1989)] have shown that, when F-actin is mixed with inert high polymer, a large number of actin filaments closely align in parallel with overlaps to form a long and thick bundle. The bundle may be designated non-polar, as the constituent filaments are random in polarity (Suzuki et al. 1989). I prepared non-polar bundles of F-actin using methylcellulose (MC) as the high polymer, exposed them to heavy meromyosin (HMM) in the presence of ATP under a light microscope, and followed their morphological changes in the continuous presence of MC. It was found that bundles several tens of micrometers long contracted to about one-third the initial length, while becoming thicker, in half a minute after exposure to HMM. Subsequently, each bundle was split longitudinally into several bundles in a stepwise manner, while the newly formed ones remained associated together at one of the two ends. The product, an aster-like assembly of actin bundles, was morphologically quiescent; that is, individual bundles never contracted upon second exposure to HMM and ATP, although they were still longer than the F-actin used. Bundles in this state consisted of filaments with parallel polarity as examined by electron microscopy. This implies that non-polar bundles were transformed into assemblies of polar bundles with ATP hydrolysis by HMM. Importantly, myosin subfragment-1 caused neither contraction nor transformation. These results are interpreted as follows. In the presence of ATP, the two-headed HMM molecule was able to cross-bridge antiparallel actin filaments, as well as parallel ones.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗
PubMed1990

Characterization of the cord-like structures emerging from the surface of influenza C virus-infected cells.

When HMV-II cells (a human malignant melanoma cell line) infected with a newly isolated influenza C strain (Yamagata/1/88) were examined by simple light microscopy, it was found that a large number of cord-like structures which had lengths up to about 500 microns or greater were emerging from the cell surface. The existence of viral glycoproteins (hemagglutinin-esterase, HE) on the surface of these huge structures was confirmed by hemadsorption experiments with erythrocytes from a variety of species as well as by immunofluorescent staining with anti-HE monoclonal antibody. Furthermore, electron microscopy revealed that numerous filamentous particles in the process of budding, each covered with a layer of surface projections approximately 13 nm in length, aggregated with their long axes parallel to form a cord-like structure visible under a light microscope. An electron-dense layer, which presumably consists of membrane protein (M), was seen in cross-sections of all filamentous virions whereas internal nucleocapsids were rarely seen. SDS-polyacrylamide gel electrophoresis of the purified cords also showed that they contained HE and M polypeptides but not nucleoprotein, confirming that long filamentous particles are mostly devoid of nucleocapsids. The emergence of cords on the cell surface was observed in various cell cultures infected with C/Yamagata/1/88 though their number and length varied markedly depending on cell type. The production of cord-like structures was also evident in HMV-II cells infected with any of several different influenza C strains, which suggests that the cord formation is a common feature of influenza C virus group.

Adsorption↗
PubMed1990

In vitro motility of skeletal muscle myosin and its proteolytic fragments.

We have compared actin-activated myosin ATPase activity, myosin binding to actin, and the velocity of myosin-induced actin sliding in order to understand the mechanism of myosin motility. In our in vitro assay, F-actin slides at a constant velocity, regardless of length. The F-actin could slide over myosin heads at KCl concentrations below a critical value (60 mM with myosin and HMM, 100 mM with S-1), and the sliding velocities were quite similar below the critical KCl concentration. However, at KCl concentrations close to the critical value, the sliding F-actin is attached to only one or a few particular points on the surface, each of which perhaps consists of a single head of myosin. The KATPase values for actin-activated ATPase were approximately 300 microM for S-1 and approximately 200 microM with HMM below the critical KCl concentration, and approximately 5,000 microM above the critical KCl concentration. This increase in KATPase is due to a drastic reduction in the binding affinity of myosin heads to F-actin, as determined by a proteolytic digestion method and direct observation by fluorescence microscopy. We also show that the Vmax of actin-activated myosin ATPase activity decreases steadily with increasing KCl concentration, even though the velocity of F-actin sliding remains unchanged. This result provides evidence that the ATPase activity is not necessarily linked to motility. We discuss possible models that do not require a tight coupling between myosin ATPase and motility.

Actin Cytoskeleton↗
PubMed1990

Influenza C virus infection in rats.

Four-week-old rats (WKA/Hkm strain) were infected intranasally with the Ann Arbor/1/50 strain of influenza C virus and examined for clinical symptoms, virus replication, and serum antibody response. Although the animals showed no definite signs of illness, the virus replicated in the nose, and the hemagglutination-inhibiting (HI) and neutralizing antibodies were produced in their sera. When the inoculum sizes of 10(6.2) and 10(3.2) PFU were used, virus was recovered from nasal homogenates between days 1 and 10, and serum HI antibody became detectable by 10 days after infection. The rats infected with 10(1.2) PFU of the virus continued to shed virus until as late as day 20 without producing serum HI antibody. The amount of virus recovered from the nose was not affected significantly by either sex, age, or strain of the rat except that a slower virus growth was seen in the LE strain. It was also observed that the rats, previously inoculated with 10(3.2) PFU of the virus, showed no virus shedding when reinfected 7 weeks later but produced virus though in low titers when reinfected 50 to 55 weeks later. Virus was also recovered from rats once inoculated with 10(1.2) PFU of the virus when challenged 7 weeks later. Thus repeated infections characteristic of human influenza C can be produced in rats under the restricted conditions.

Animals↗
PubMed1989

Measurement of ATPase activity of immobilized myosin heads.

Myosin, heavy meromyosin, and myosin subfragment-1 (S-1) were immobilized on the inner surfaces of glass capillary tubes, the inside walls of which had been coated with nitrocellulose. The ATPase activities of the immobilized proteins were measured using radiolabeled ATP and electrophoretic separation of the reaction products. The activity was proportional to the amount of immobilized protein. Activation by actin of the ATPase was also observed.

Actins↗
PubMed1987

Stability properties of oxymyoglobin from chicken gizzard smooth muscle.

1. Oxymyoglobin (MbO2) was isolated directly from the smooth muscle of chicken gizzard and was examined for its spectral and stability properties. 2. When compared with sperm whale MbO2 as a reference, chicken gizzard MbO2 was found to be much more susceptible to autoxidation. Its pH-dependence was therefore analyzed in terms of an "acid-catalyzed three-state model". 3. The complete amino acid sequence of the myoglobin was also determined. Its hydropathy profile revealed that the region corresponding to the distal side of the heme iron appears to be less hydrophobic.

Amino Acid Sequence↗
PubMed1986

Dissociation between plasma and atrial content of atrial natriuretic polypeptide (ANP) following sodium load in rats.

To investigate the time course effect of sodium intake on release and synthesis of atrial natriuretic polypeptide (ANP), plasma and atrial content of ANP were measured in rats which had been fed either a high or a low salt diet for 1, 3, 7, 14 and 35 days. Plasma ANP in rats fed the high salt diet for one day was significantly higher than in those fed the low salt diet. However, there were no significant differences between the groups fed either the high or the low salt diet for 3 days or more. In contrast to the direction of change in plasma ANP, atrial content of ANP in rats fed the high salt diet for one day tended to be lower and was significantly lower in those fed for 3 and 7 days than in the low salt diet group, while there were no significant differences between both groups that were fed for 14 and 35 days. These results suggest that ANP is rapidly released into the circulation when sodium is loaded, however, the atrial storage of ANP remains depleted for about one week.

Animals↗
PubMed1986

[Hygienic effect of periodical draining from auto-watering piping for laboratory animal breeding].

To prevent the bacterial contamination of the drinking water, we developed a periodical draining machine system which were composed of the electromagnetic valve and the time switch. The machine system is able to replace standing water with fresh water on optional volumes and intervals. The total bacterial numbers of standing water were counted as an indicator of the bacterial contamination. The number of total bacteria were reduced to less than 5 per ml by working the machine system on 6-hour-interval with replacing twice as much as standing water, although more than 10(3) per ml of the bacteria were found when the system was not operated. It was demonstrated that the periodical draining of the machine prevented the drinking water in auto-watering piping from bacterial contamination.

Animal Husbandry↗