• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.3
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• pp.447-463
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• 2001

Dendroaspis natriuretic peptide (DNP), a fourth member of the natriuretic peptide isolated from the venom of the Dendroaspis angusticeps snake, has been reported to be present in human plasma and atrial myocardium and caused vasorelaxation and diuresis in experimental animals. However, it is uncertain whether they are present in peripheral organs other than the heart and its further physiological roles also remains to be clarified. To assess the possible physiological role of DNP in the salivary glands, I investigated the localization of DNP peptide in the rat salivary glands by immunohistochemistry and the binding sites for radiolabelled DNP in the rat salivary glands and oral mucosa using in vitro autoradiography. DNP immunoreactivity was widely distributed in the submandibular, sublingual and parotid glands, particularly in the ducts such as the intercalated and striated ducts, where atrial natriuretic peptide (ANP) was colocalized in consecutive sections, but not in acini. High density $^{125}I-DNP$ binding sites were localized in the epithelia of the tongue and hard palate, while low density binding sites for $^{125}I-DNP$ were also distributed in the submandibular, sublingual, and parotid glands. In the hard palate and tongue, the precise location of this binding was revealed on the basal and parabasal cells of the epithelia by emulsion microautoradiography. These results suggest that DNP may not only have a role in the salivary glands but also play a role in the regulation of growth in the oral epithelium, particularly in the hard palate and tongue.

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.2
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• pp.82-86
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• 1998

The maltose binding protein (MBP) fusion protein system is a versatile tool to express and isolate recombinant proteins in E. coli. In this system, MBP fusion proteins are efficiently isolated from whole cell lysate using amylose conjugated agarose beads and then eluted by competition with free maltose. Since MBP is a rather large molecule (∼42 kDa), for further experiments, the MBP part is usually proteolytically cleaved from the fusion protein and subsequently removed by ion-exchange chromatography or rebinding to amylose columns after washing out excess and MBP-bound maltose. In the present study, we have developed an improved method for the removal of cleaved MBP, which is advantageous over conventional methods. In this method, factor Xa cleaved MBP fusion proteins were incubated with Sepharose beads conjugated with MBP specific monoclonal antibodies and then precipitated buy centrifugation, resulting in highly purified proteins in the supernatant.

• Molecules and Cells
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• v.19 no.1
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• pp.54-59
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• 2005

Deoxyribonuclease I (DNase I) is a divalent cation dependent endonuclease and thought to be a significant barrier to effective gene delivery. The only known DNase I-specific inhibitor is monomeric actin which acts by forming a 1:1 complex with DNase I. Its use, however, is restricted because of tendency to polymerize under certain conditions. We screened two random phage peptide libraries of complexity $10^8$ and $10^9$ for DNase I binders as candidates for DNase I inhibitors. A number of DNase I-binding peptide sequences were identified. When these peptides were expressed as fusion proteins with Escherichia coli maltose binding protein, they inhibited the actin-DNase I interaction ($IC_{50}=0.1-0.7{\mu}M$) and DNA degradation by DNase I ($IC_{50}=0.8-8{\mu}M$). Plasmid protection activity in the presence of DNase I was also observed with the fusion proteins. These peptides have the potential to be a useful adjuvant for gene therapy using naked DNA.

• International Journal of Industrial Entomology and Biomaterials
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• v.25 no.1
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• pp.115-121
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• 2012

The bumblebee Bombus terrestris is widely used in greenhouses to pollinate crops. Here, we report the molecular cloning and characterization of chymotrypsin inhibitor and chitin-binding protein homologs from B. terrestris. Two cDNAs encoding chymotrypsin inhibitor (Bt-CI) and chitin-binding protein (Bt-CBP) homologs were cloned from B. terrestris. Gene sequence analysis showed that Bt-CI gene consists of three exons encoding 75 amino acids, including a predicted 20-amino acid signal peptide, while Bt-CBP consists of two exons encoding 78 amino acids, including a predicted 26-amino acid signal peptide. The mature Bt-CI and Bt-CBP peptides contain ten and six conserved cysteine residues, respectively. Database searches using the deduced sequences of Bt-CI and Bt-CBP showed similarity to those from B. impatiens (96% peptide sequence identities). Bt-CI and Bt-CBP were expressed in both the venom gland and fat body of B. terrestris worker bees. The recombinant Bt-CI and Bt-CBP peptides were expressed in baculovirus-infected insect cells. Taken together, our findings describe the molecular characterization of Bt-CI and Bt-CBP from B. terrestris.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3601-3606
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• 2012

Structural properties of a small hexapeptide molecule modeled after metal-binding siderochrome immersed in a room-temperature ionic liquid (RTIL) are studied via molecular dynamics simulations. We consider two different RTILs, each of which is made up of the same cationic species, 1-butyl-3-methylimidazolium ($BMI^+$), but different anions, hexafluorophosphate ($PF_6{^-}$) and chloride ($Cl^-$). We investigate how anionic properties such as hydrophobicity/hydrophilicity or hydrogen bonding capability affect the stabilization of the peptide in RTILs. To examine the effect of peptide-RTIL electrostatic interactions on solvation, we also consider a hypothetical solvent $BMI^0Cl^0$, a non-ionic counter-part of $BMI^+Cl^-$. For reference, we investigate solvation structures in common polar solvents, water and dimethylsulfoxide (DMSO). Comparison of $BMI^+Cl^-$ and $BMI^0Cl^0$ shows that electrostatic interactions of the peptide and RTIL play a significant role in the conformational fluctuation of the peptide. For example, strong electrostatic interactions between the two favor an extended conformation of the peptide by reducing its structural fluctuations. The hydrophobicity/hydrophilicity of RTIL anions also exerts a notable influence; specifically, structural fluctuations of the peptide become reduced in more hydrophilic $BMI^+Cl^-$, compared with those in more hydrophobic $BMI^+PF_6{^-}$. This is ascribed to the good hydrogen-bond accepting power of chloride anions, which enables them to bind strongly to hydroxyl groups of the peptide and to stabilize its structure. Transport properties of the peptide are examined briefly. Translations of the peptide significantly slow down in highly viscous RTILs.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.218-223
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• 1998

Casein was hydrolyzed by alcalase to produce iron binding peptide (IBP). IBP was effectively separated from casein hydrolysates by immobilized $Fe^{3+}$ affinity chromatography and further purified by reverse phase chromatography. $25,\;50\;and\;100\;{\mu}g/mL$ of IBP solubilized $4.2,\;5.7\;and\;7.1\;{\mu}g$ of ferric at duodenum condition $(pH\;6,\;37^{\circ}C)$, respectively. According to the result of MALDI analysis, molecular weight of IBP was determined to 2,175 dalton. IBP was mainly composed of proline (24.5 mol%), lysine (15.7 mol%), and glutamine or glutamic acid (14.9 mol%) and its N-terminal sequence was Met-Ala-Pro-Lys-His. According to the information obtained from molecular weight, amino acids composition and N-terminal sequence of IBP, it was evident that IBP was from f102-119 of ${\beta}-casein$.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.1052-1056
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• 1997

When casein was hydrolyzed by trypsin, alcalase, neutrase, protamax, and S. aureus type V8, peptides $(100\;{\mu}g/mL)$ which were produced by trypsin and alcalase solubilized $6.42\;and\;2.37\;{\mu}g/mL)$ of added irons at pH 6, respectively, while peptides which were produced by other proteases solubilized less than $1\;{\mu}g/mL$. Peptides produced by trypsin and alcalase were fractionated to 10 fractions on a reverse phase column and each fraction was tested for its iron solubilizing ability at pH 6. Among peptides produced by trypsin, fraction 5 showed the highest iron solubilizing ability $(2.33\;{\mu}g/mL)$. In the case of alcalase, fraction 7 showed the highest iron solubilizing ability $(1.56\;{\mu}g/mL)$. To isolate iron binding peptides from peptides produced by trypsin and alcalase, immobilized iron affinity chromatography which irons were chelated to imino diacetic acids in chelating sepharose fast flow were utilized. Our results showed that immobilized iron affinity chromatography was an effective method to isolate iron binding peptides produced by either trypsin or alcalase from milk casein.

• Molecules and Cells
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• v.20 no.1
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• pp.83-89
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• 2005

HtrA2/Omi is a mammalian mitochondrial serine protease homologous to the E. coli HtrA/DegP gene products. Recently, HtrA2/Omi was found to have a dual role in mammalian cells, acting as an apoptosis-inducing protein and being involved in maintenance of mitochondrial homeostasis. By screening a human brain cDNA library with $A{\beta}$ peptide as bait in a yeast two-hybrid system, we identified HtrA2/Omi as a binding partner of $A{\beta}$ peptide. The interaction between $A{\beta}$ peptide and HtrA2/Omi was confirmed by an immunoblot binding assay. The possible involvement of HtrA2/Omi in $A{\beta}$ peptide metabolism was investigated. In vitro peptide cleavage assays showed that HtrA2/Omi did not directly promote the production of $A{\beta}$ peptide at the ${\beta}/{\gamma}$-secretase level, or the degradation of $A{\beta}$ peptide. However, overexpression of HtrA2/Omi in K269 cells decreased the production of $A{\beta}40$ and $A{\beta}42$ by up to 30%. These results rule out the involvement of HtrA2/Omi in the etiology of Alzheimer's disease. However, the fact that overexpression of HtrA2/Omi reduces the generation of $A{\beta}40$ and $A{\beta}42$ suggests that it may play some positive role in mammalian cells.

• Journal of Microbiology and Biotechnology
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• v.20 no.4
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• pp.821-827
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• 2010

Gene delivery that provides targeted delivery of therapeutic genes to the cells of a lesion enhances therapeutic efficacy and reduces toxic side effects. This process is especially important in cancer therapy when it is advantageous to avoid unwanted damage to healthy normal cells. Incorporating cancer-specific ligands that recognize receptors overexpressed on cancer cells can increase selective binding and uptake and, as a result, increase targeted transgene expression. In this study, we investigated whether a peptide capable of homing to hepatocellular carcinoma (HCC) could facilitate targeted gene delivery by cationic liposomes. This homing peptide (HBP) exhibited selective binding to a human hepatocarcinoma cell line, HepG2, at a concentration ranging from 5 to 5,000 nM. When conjugated to a cationic liposome, HBP substantially increased cellular internalization of plasmid DNA to increase the transgene expression in HepG2 cells. In addition, there was no significant enhancement in gene transfer detected for other human cell lines tested, including THLE-3, AD293, and MCF-7 cells. Therefore, we demonstrate that HBP provides targeted gene delivery to HCC by cationic liposomes.

• Interdisciplinary Bio Central
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• v.4 no.2
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• pp.5.1-5.9
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• 2012

Small peptide tags such as c-myc, HA, or FLAG tag have facilitated efficient Western-blotting of proteins of interest especially when specific antibodies for the proteins are not available. However, the conventional Western-blotting requires the multi-steps process taking at least several hours up to two days. With examples of various applications, here we show a convenient and time-saving method for protein detection which employs a fluorescent chemical BDED and its binding peptide RC-tag. And we propose "Estern staining", as a standard term for protein detection method using fluorescent chemicals and their binding small peptide tags. Eastern staining may substitutes for the time-consuming "immuno-staining" in many versatile applications.