• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.65.1-65
• /
• 2003

In addition to the five well-characterized genes of Tobacco mosaic virus (TMV), this virus contains a sixth open reading frame (ORF6) that encodes a 4.8 kDa protein. TMV ORF6 overlaps the ORFs encoding the 30 kDa movement protein and the adjacent 17.5 kDa capsid protein. Although the 4.8 kDa protein could not be detected in vivo, alteration of the AUG codons of this ORF resulted in a mutant virus that attenuated the virulence of the mutated TMV in Nicotiana benthamiana, but not N. tabacum (tobacco). These sequence changes did not affect either the replication or movement of the mutated TMV. Expression of TMV ORF6 from the virus expression vector Potato virus X (PVX) intensified the virulence of this virus in N. benthmiana, but not tobacco, while expression of TMV ORF6 from the virus expression vector Tobacco rattle virus enhanced the pathogenicity observed in both N. benthamima and tobacco. Thus, the TMV ORF6 is a host- and virus-specific. virulence factor. However, two separate assays indicated that the TMV 4.8 kDa protein was not a suppression of RNA silencing. A fusion protein formed between the TMV 4.8 kDa protein and the green fluorescent protein was expressed from the PVX vector and localized to plasmodesmata. Possible roles of the 4.8 kDa protein in pathogenicity will be discussed

• The Journal of the Korea Contents Association
• /
• v.8 no.1
• /
• pp.259-271
• /
• 2008

We propose a protein function finding algorithm that is able to predict specific molecular function for unannotated proteins through domain analysis from protein-protein network. To do this, we first construct protein-protein interaction(PPI) network in Saccharomyces cerevisiae from MIPS databases. The PPI network(proteins; 3,637, interactions; 10,391) shows the characteristics of a scale-free network and a hierarchical network that proteins with a number of interactions occur in small and the inherent modularity of protein clusters. Protein-protein interaction databases obtained from a Y2H(Yeast Two Hybrid) screen or a composite data set include random false positives. To filter the database, we reconstruct the PPI networks based on the cellular localization. And then we analyze Hub proteins and the network structure in the reconstructed network and define structural modules from the network. We analyze protein domains from the structural modules and derive functional modules from them. From the derived functional modules with high certainty, we find tentative functions for unannotated proteins.

• The Korean Journal of Physiology and Pharmacology
• /
• v.18 no.2
• /
• pp.155-161
• /
• 2014

Overexpression of amyloid precursor protein with the Swedish mutation causes abnormal hyperphosphorylation of the microtubule-associated protein tau. Hyperphosphorylated isoforms of tau are major components of neurofibrillary tangles, which are histopathological hallmarks of Alzheimer's disease. Protein phosphatase 2A (PP2A), a major tau protein phosphatase, consists of a structural A subunit, catalytic C subunit, and a variety of regulatory B subunits. The B subunits have been reported to modulate function of the PP2A holoenzyme by regulating substrate binding, enzyme activity, and subcellular localization. In the current study, we characterized regulatory B subunit-specific regulation of tau protein phosphorylation. We showed that the PP2A B subunit PPP2R2A mediated dephosphorylation of tau protein at Ser-199, Ser-202/Thr-205, Thr-231, Ser-262, and Ser-422. Down-regulation of PPP2R5D expression decreased tau phosphorylation at Ser-202/Thr-205, Thr-231, and Ser-422, which indicates activation of the tau kinase glycogen synthase kinase 3 beta ($GSK3{\beta}$) by PP2A with PPP2R5D subunit. The level of activating phosphorylation of the $GSK3{\beta}$ kinase Akt at Thr-308 and Ser-473 were both increased by PPP2R5D knockdown. We also characterized B subunit-specific phosphorylation sites in tau using mass spectrometric analysis. Liquid chromatography-mass spectrometry revealed that the phosphorylation status of the tau protein may be affected by PP2A, depending on the specific B subunits. These studies further our understanding of the function of various B subunits in mediating site-specific regulation of tau protein phosphorylation.

• Journal of Nutrition and Health
• /
• v.24 no.1
• /
• pp.20-29
• /
• 1991

This study was carried out to compare the protein quality of lamb and beef meat. by feeding to growing rats. Sixty weanling rats, 30 males and 30 females, were blocked into 12 groups(6 gruops of males and 6 groups of females). They were fed casein. beef, or lamb as a protein source at two levels, 6 and 15%, for 5 weeks. The amount of food intake. food efficiency ratio, protein efficiency ratio. body weight gain. and the weights of skeletal muscles and liver were measured. Nitrogen retention, protein content in the liver and skeletal muscles, and the levels of protein and cholesterol in the serum were also assayed. Summarzing the results, there were no significant differences between lamb and beef on the growth and nitrogen utilization in the rats fed same percentage of protein diet. However. rats fed 15% protein diet showed significantly higher growth rate than those fed 6%. Therefore, it can be concluded that lamb is as good a protein food as beef in terms of protein quality.

• Journal of Microbiology and Biotechnology
• /
• v.14 no.1
• /
• pp.162-166
• /
• 2004

Phage P22 tailspike is a thermostable homotrimeric protein, and temperature-sensitive folding (tsf) and global suppressor mutations affect its folding yields at elevated temperatures. We earlier suggested that the folding of the tailspike protein in Escherichia coli requires an unidentified molecular chaperone. Accordingly, in the present study, the interactions of purified DnaK, DnaJ, and GrpE heat-shock proteins with the tailspike protein were investigated during the translation and folding of the protein. The cotranslational addition of DnaJ to the tailspike protein resulted in the arrest of folding, when Dnak and GrpE were missing. However, the presence of DnaK, DnaJ, and GrpE had no effect on the folding yield of the tails pike protein, thus, providing evidence for the binding of the nascent tailspike protein with DnaJ protein, a member of DnaK chaperoning cycle.

• Journal of Life Science
• /
• v.8 no.1
• /
• pp.14-26
• /
• 1998

a- and c-raf protein kinase in the brain of rat, the protein pattern of cerebellum during postnatal development of rat by polyacryamide gel electrophoresis, and the existence of c-raf protein kinase by using Western blotting method. The results were as follows: The cytoplasm of Purkinje cells was, in general, strongly labeled with the antibodies of a- and c-raf protein kinases in the cortex regions such as Pyramis cerebelli, Unula, Nodulus, Paraflocculus, and Flocculus. C-raf protein kinase appeared stronger immunoreactivity than a-raf protein kinase. In peripheral of cytoplasm of Nucleus emboliformis, A-raf Protein kinase was labeled markedly. During postnatal development, the protein of 38,000 dalton increased gradually in the cytosolic fraction of cerebellum, and the protein of 260,600 dalton appeared in the membrane fraction of cerebellum. By immunoblotting method, the protein band of 74,000 dalton was detected in crude and cytosolic fractions, but it was not exhibited in membrane fraction, In this fact, it was identified that a - and c-raf proteins were distributed throughout neuronal cells, especially in the Purkinje cells, in normal cerebellum cortex of rat. Also, this phenomenon was assumed that raf protein kinase in cytoplasm of neuronal cell had to do with a certain functional mechanism and signal transduction of neurotransmitter as Protein kinase C.

• Journal of environmental and Sanitary engineering
• /
• v.12 no.2
• /
• pp.59-64
• /
• 1997

For purification of a 70kDa toxic protein of mosquitocidal delta-endotoxin from B. thuringiensis strain H9B, immuno-affinity chromatography was performed. After separation of 70kDa toxic proteins from the delta-endotoxin of the strain H9B on SDS-PAGE, the 70kDa toxic protein was subcutaneously injected into rabbit for making a polyclonal antibody. A anti-70kDa toxic protein was purified by a column chromatography packed with protein A-sepharose 4B gels. The 70kDa toxic protein from delta-endotoxin of the strain H9B was also purified by an immuno-affinity chromatography packed with CNBr-activated sepharose 4B gels conjugated anti-70kDa toxic protein after elution with 1/10M citric acid-1/5M Na$_{2}$HPO$_{4}$ buffer(pH3.2) containing 0.5M NaCl. The 70kDa toxic protein was purified through only one step-separation system, was demonstrated by SDS-PAGE and immunoblot.

• Preventive Nutrition and Food Science
• /
• v.15 no.4
• /
• pp.282-286
• /
• 2010

To isolate a calcium-binding peptide from chlorella protein hydrolysates, chlorella protein was extracted and hydrolyzed using Flavourzyme, a commercial protease. The degree of hydrolysis and calcium-binding capacity were determined using trinitrobenzenesulfonic acid and orthophenanthroline methods, respectively. The enzymatic hydrolysis of chlorella protein for 6 hr was sufficient for the preparation of chlorella protein hydrolysates. The hydrolysates of chlorella protein were then ultra-filtered under 5 kDa as molecular weight. The membrane-filtered solution was fractionated using ion exchange, reverse phase, normal phase chromatography, and fast protein liquid chromatography to identify a calcium-binding peptide. The purified calcium-binding peptide had a calcium binding activity of 0.166 mM and was determined to be 700.48 Da as molecular weight, and partially identified as a peptide containing Asn-Ser-Gly-Cys based on liquid chromatography/electrospray ionization tandem mass spectrum.

• The Korean Journal of Zoology
• /
• v.32 no.2
• /
• pp.153-162
• /
• 1989

Expedments were perfonned to examine the role of cAMP-dependent protein kinase (PK-A) and diacylglycerol-dependent protein kinase (PK-C) during the meiodc resumption and the first mitotic cell cycle of mouse embryogenesis. Mejoric GV oocytes and one-cell embryos derived from in vitro fertilization were cultured in vitro, and morphological changes in response to activators of PK-A and PK-C were examined. Treatments with a membrane-permeable cAMP analog, dbcAMP (0.1 mg/mi), phosphodiesterase inhibitor, IBMX (0.1 mM), biologically active phorbol ester, WA (10 nglmi), or a synthetic diacylglycerol, sn-diC8 inhibited resumption of melosis. Combination of PK-A and PK-C activator brought about furiher inhibition. On the contrary, dbcAMP (0.1 mg/mi), IBMX (0.2 mM), WA (10 nglml), and sn-diC8 (0.5 mM) did not inhibit pronucleus membrane breakdown (PNBD) when added S or G2 phase of cell cycle. However, activators of PK-C inhibited cleavage of one-cefl embryos. This result indicates that the action mechanism of PK-A and PK-C on dissolution of nuclear membrane in primary meiotic arrest oocytes may be different from that of mitotic one-cell embryos.

• Nutrition Research and Practice
• /
• v.4 no.5
• /
• pp.375-382
• /
• 2010

The precise effects of protein intake on fractional synthesis rate (FSR) of muscle protein are still under debate. The sample size of these studies was small and the conclusions in young and elderly subjects were inconsistent. To assess the effect of dietary protein intake on the FSR level, we conducted a meta-analysis of controlled protein intake trials. Random-effects models were used to calculate the weighted mean differences (WMDs). Ten studies were included and effects of short-term protein intake were evaluated. In an overall pooled estimate, protein intake significantly increased the FSR (20 trials, 368 participants; WMD: 0.025%/h; 95%CI: 0.019-0.031; P < 0.0001). Meta-regression analysis suggested that the protein dose was positively related to the effect size (regression coefficient = 0.108%/h; 95%CI: 0.035, 0.182; P = 0.009). A subgroup analysis indicated that protein intake significantly increased FSR when the protein dose was ${\leq}$ 0.80 g/kg BW (16 trials, 308 participants; WMD: 0.027%/h; 95%CI: 0.019-0.031; P < 0.0001), but did not affect FSR when the protein dose was > 0.80 g/kg BW (4 trials, 60 participants; WMD: 0.016%/h; 95%CI: 0.004-0.029; P = 0.98). In conclusion, this study is the first integrated results showing that a short-term protein intake is effective at improving the FSR of muscle protein in the healthy elderly as well as young subjects. This beneficial effect seems to be dose-dependent when the dose levels of protein range from 0.08 to 0.80 g/kg BW.