• Bulletin of the Korean Chemical Society
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• v.35 no.4
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• pp.1087-1090
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• 2014

A simple and general method that selectively introduces metal binding sites into a protein can greatly increase the ability to design and biosynthesize artificial metalloproteins. Here, we report the incorporation of a phenanthroline-containing amino acid (Phen-Ala) into proteins in Escherichia coli by using the $tRNA{^{Tyr}}_{CUA}$ and tyrosyl aminoacyl-tRNA synthetase pair (BpyRS) from Methanococcus jannaschii, which was originally developed for a bipyridine-containing amino acid (Bpy-Ala). The incorporation efficiency of BpyRS for Phen-Ala was comparable to that for Bpy-Ala. Because of its high metal-binding ability and characteristic spectral properties, Phen-Ala can be a useful alternative to the existing metal-chelating amino acids for the design and synthesis of artificial metalloproteins.

• Macromolecular Research
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• v.14 no.3
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• pp.324-330
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• 2006

Four different molecularly imprinted polymers (MIPs) were prepared using resveratrol as the template, methacrylic acid (MAA) or acrylamide (AA) as functional monomers, 2,2-azobisisobutyronitrile (AIBN) as the initiator, and thermo- or photo-induced polymerization. The ability of the different polymers to rebind selectively not only the template but also other phenols was evaluated. In parallel, the influence of the different templates and functional monomers used during polymer syntheses on the performance of the obtained MIPs was also studied through different rebinding experiments. The binding ability and selectivity of the polymer were studied by static balance method and Scatchard analysis. It was concluded that AA-based polymer by photo-induced polymerization presents the best properties to be used as a selective absorbent for the extraction of resveratrol.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 1998.07a
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• pp.41-42
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• 1998

The changes in calcium binding protein(CBP) of mouse epididymal sperm during their post-testicular differentiation were analyzed by two-dimensional SDS-PAGE. According to dpididymal maturation, capacitation and acrosome reaction of spermatozoa, both quantitative and qualitative changes of CBPs in the epididymal sperm was detected. It suggested that the development of fertilizing ability of epididymal sperm was closely related to the changes in the CBPs profiles of sperm during epidiyaml transit.

• BMB Reports
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• v.34 no.3
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• pp.194-200
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• 2001

Secreted arginase from Evernia prunastri thallus has been purified 616-fold from the incubation medium. Purified arginase was resolved as only one peak in a capillary electrophoresis with a pI value of 5.35. The protein contained high amounts of acidic amino acids, such as Asx and Glx, and a relatively high quantity of Ser and Gly. The molecular mass of native, purified arginase was estimated as about 26 kDa by SE-HPLC. Substrate saturated kinetic showed a typical Michaelis-Menten relationship with a K_m value of 3.3 mM L-arginine. Atranorin behaved as a mixed activator of the enzyme (apparent $K_m$ = 0.96 mM); whereas evernic and usnic acid were revealed as non competitive inhibitors (apparent $K_m$ values were 3.16 mM and 3.05 mM, respectively). Kinetics of atranorin binding indicated that saturation was reached from 0.18 ${\mu}mol$ of the total atranorin and the occurrence of multiple sites for the ligand. This agrees with a possible aggregation of several enzyme subunits during the interaction process. A value of binding sites of about 12 was obtained. The binding of evernic acid was saturated from 23 nmol of total phenol. The number of binding sites was about 5. The loss of the binding ability of evernic acid could be interpreted as a single negative cooperatively. Usnic acid behaves in a similar way to evernic acid, although the binding saturation occurs at $0.14\;{\mu}moles$ of the ligand. This binding appears to be unspecific, and has 28 usnic acid binding sites to the protein.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.170-180
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• 1997

Cariogenicity of the bacteria is attributed to their binding capacity to the teeth. Bacterial attachment to oral surfaces is an essential step for colonization and subsequently infection. Therefore, it is conceivable that caries prevention can be achieved fundamentally by inhibition of bacterial attachment. The rationale for caries prevention through the use of sugar substitutes or limited use of sugar has been revealed. Among many sugar substitutes, xylitol has been shown to exhibit the most profound cariostatic effect, inhibiting glucose metabolism and possibly binding of mutans streptococci. The purpose of this study was to examine the effect of xylitol on binding of different species of oral bacteria. The effect of xylitol on binding of [$^3H$]-labeled oral bacteria to hydroxyapatite coated with human saliva(SHA) as a model for the pellicle-coated tooth surfaces was investigated. The strains of oral bacteria used in this study were A. viscosus T14V, A. viscosus WVU627, P. gingivaiis 2561, P. gingivalis A7Al-28, S. gordonii G9B, S. gordonii Challis, S. sobrinus 6715, S. mutans UA101, S. mutans KPSK -2, S. mutans T8, and S. mutans UA130. The obtained results were as follows: 1. P. gingivalis A7 Al-28, S. mutans UA130, S. mutans T8 grown with xylitol showed greater binding to SHA than the organism grown without xylitol. Among these, S. mutans T8 showed the greatest rate of increase in its binding to SHA ; 8-fold increase in its binding with xylitol. 2. S. mutans KPSK -2 grown with xylitol showed 2 times lesser binding to SHA than the organism grown without xylitol. 3. Binding ability of the remaining strains grown with xylitol to SHA was almost same as that of the organisms grown without xylitol. The overall results suggest that use of xylitol in the oral cavity may affect the complex oral bacterial ecosystem.

• The Korean Journal of Ecology
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• v.19 no.6
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• pp.519-527
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• 1996

To examine the possibility of biomonitoring of heavy metal removal ability and soil, a study was performed to investigate the heavy metal removal ability and metal-binding protein (MBP) as detoxification process using Oenanthe stolonifera. After O. stolonifera was exposed to individuals (cadmium, zinc) and mixture (cadmium+zinc)for 4 days, removal rate of heavy metal and pH in the treatment medium was measured. MBP was assayed by means of ion exchange column chromatography. The exposure to mixture (Cd:76.8%, Zn:75%) rather than individuals (Cd:82.9%, Zn:90.4%) showed a synergism raising the toxic effect. Initial removal rate was different for each heavy metal : in case of exposure to cadmium it was over 60% on day 1, while for zinc it was 75~90% on day 4. Throughout the experimental period, pH value of treatment medium continuously decreased, since cortex in the roots may secret organic acid to adjust and prevent toxicity of metals. The existence or MBP in the 70~80 fraction and the presence of Zn-enzyme pool was ascertained with the column chromatography. This study demonstrated a possibility that heavy utilized as a biomarker of heavy metal pollution.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.11
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• pp.1622-1629
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• 2013

The objective of this study was to develop a new method to separate phosvitin from egg yolk without using organic solvents. Phosvitin was extracted from yolk granules using 10% NaCl or 10% $(NH_4)_2SO_4$ (final concentration) and then treated with heat to precipitate the lipoproteins from the extracted solution. The optimal pH for the phosvitin extraction from yolk granules was determined, and the iron-binding ability of the extracted phosvitin (final product) was tested. Adding 10% $(NH_4)_2SO_4$ disrupted the granules, and the subsequent thermal treatment at $90^{\circ}C$ for 1 h precipitated low density and high density lipoproteins, which enabled separation of phosvitin by centrifugation. The phosvitin concentration in the extract was significantly higher when the pH of the solution was adjusted to pH ${\geq}9$. The purity and recovery rate of phosvitin at the end of the separation process were approximately 78% and 56%, respectively. The separated phosvitin was confirmed to have ferrous and ferric iron binding ability. The advantages of this new method compared with the traditional methods include no organic solvents and high-priced equipment are needed for the separation. Also, this method is more environment and consumer friendly than that of the traditional methods.

• Journal of Microbiology
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• v.44 no.3
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• pp.293-300
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• 2006

The Escherichia coli heat-labile enterotoxin B subunit (HLT-B) is one of the most powerful mucosal immunogens and known mucosal adjuvants. However, the induction of high levels of HLT-B expression in E. coli has proven a difficult proposition. Therefore, in this study, the HLT-B gene was cloned from pathogenic E. coli and expressed as a fusion protein with GST (glutathion S-transferase) in E. coli BL2l (DE3), in an attempt to harvest a large quantity of soluble HLT-B. The culture conditions, including the culture media used, temperature, pH and the presence of lactose as an inducer, were all optimized in order to obtain an increase in the expression of soluble GST-rHLT-B. The biological activity of the purified rHLT-B was assayed in a series of GMI-ELISA experiments. The findings of these trials indicated that the yield of soluble recombinant GST-rHLT-B could be increased by up to 3-fold, as compared with that seen prior to the optimization, and that lactose was a more efficient alternative inducer than IPTG. The production of rHLT-B, at 92 % purity, reached an optimal level of 96 mg/l in a 3.7 L fermentor. The specific GM1 binding ability of the purified rHLT-B was determined to be almost identical to that of standard CTB.

• Journal of Internet Computing and Services
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• v.8 no.6
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• pp.21-28
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• 2007

Hierarchical Mobile IPv6 improves performance of Mobile IPv6 by managing Binding Update in terms of location, With improved handover delay, realization of delay-sensitive services (e,g, VoIP or video streaming) has become more persuadable, Comparing with Mobile IPv6, however, Hierarchical Mobile IPv6 brings security threats related to Local Binding Update to mobile network, In the RFC 4140, specific methods to authenticate Local Binding Update message are not explicitly presented. It is essential that design secure architecture to address problems related to authenticating Local Binding Update, Many secure suggestions for Local Binding Update, however, concentrate on infrastructure-based solutions such as AAA PKI. These approaches may cause scalability problem when the suggested solutions are applied to real network. Therefore we suggest authentication method that doesn't require infrastructure, In addition to authentication of Local Binding Update, our method also provides mobile node with power saving ability.

• BMB Reports
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• v.40 no.1
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• pp.44-52
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• 2007

Kinesins, as a kind of microtubule-based motor proteins, have a conserved microtubule-binding site in their motor domain. Here we report that two homologous kinesins in Arabidopsis thaliana, KatB and KatC, contain a second microtubule-binding site in their tail domains. The prokaryotic-expressed N-terminal tail domain of the KatC heavy chain can bind to microtubules in an ATP-insensitive manner. To identify the precise region responsible for the binding, a serious of truncated KatC cDNAs encoding KatC N-terminal regions in different lengths, KatC1-128, KatC1-86, KatC1-73 and KatC1-63, fused to Histidine-tags, were expressed in E. coli and affinity-purified. Microtubule cosedimentation assays show that the site at amino acid residues 74-86 in KatC is important for microtubule-binding. By similarity, we obtained three different lengths of KatB N-terminal regions, KatB1-384, KatB1-77, and KatB1-63, and analyzed their microtubule-binding ability. Cosedimentation assays indicate that the KatB tail domain can also bind to microtubules at the same site as and in a similar manner to KatC. Fluorescence microscopic observations show that the microtubule-binding site at the tail domain of KatB or KatC can induce microtubules bundling only when the stalk domain is present. Through pull-down assays, we show that KatB1-385 and KatC1-394 are able to interact specifically with themselves and with each other in vitro. These findings are significant for identifying a previously uncharacterized microtubule-binding site in the two kinesin proteins, KatB and KatC, and the functional relations between them.