• Journal of Microbiology and Biotechnology
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• v.16 no.11
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• pp.1784-1790
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• 2006

Bacillus anthracis is a causative agent of anthrax. Anthrax toxins are composed of a protective antigen (PA), lethal factor (LF), and edema factor (EF), in which the PA is a central mediator for the delivery of the two enzymatic moieties LF and EF. Therefore, the PA has been an attractive target in the prevention and vaccinization for anthrax toxin. Recently, it has been reported that the molecule consisting of multiple copies of PA-binding peptide, covalently linked to a flexible polymer backbone, blocked intoxification of anthrax toxin in an animal model. In the present study, we have screened novel diverse peptides that bind to PA with a high affinity (picomolar range) from an M13 peptide display library and characterized the binding regions of the peptides. Our works provide a basis to develop novel potent inhibitors or diagnostic probes with a diverse polyvalence.

• BMB Reports
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• v.31 no.5
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• pp.515-518
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• 1998

Adhesive interaction of the platelet glycoprotien IIb-IIIa (GP IIb-IIIa) with a plasma protein, such as fibrinogen, plays an important role in thrombosis and hemostasis. The specific sequence Arg-Gly-Asp (RGD) is critical for the binding of fibrinogen to platelet. To examine and characterize the GP IIb-IIIa antagonist from natural sources, we have developed a simple enzyme-linked immunosorbant assay (ELISA) system. The GP IIb-IIIa complex was purified to homogeneity from platelet Iysates by the combination of two affinity chromatographic methods using the synthetic RGD peptide (GRGDSPK)-immobilized Sepharose and wheat germ lectin-Sepharose. The synthetic peptide GRGDSP inhibits GP IIb-IIIa binding to immobilized fibrinogen with an $IC_{50}$ of $1.5\;{\mu}M$. Venoms of three different snake species and a Korean scolopendra extract have strong antagonistic activities for the binding of human fibrinogen to the platelet GP IIb-IIIa complex. The $IC_{50}$ values of the snake venom s and scolopendra were in the range of $5.5\;{\mu}g$ to $60\;{\mu}g$. These results provide meaningful information for developing antiplatelet agents.

• Applied Biological Chemistry
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• v.50 no.4
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• pp.257-261
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• 2007

Tolaasin, a peptide toxin produced by Pseudomonas tolaasii, causes a serious disease on the cultivated mushrooms, known as brown blotch disease. Hemolysis using red blood cells was designed to measure the cytotoxicity of tolaasin molecules. Since tolaasin has two amine groups near the C-terminus, its membrane binding will be dependent on the ionic states of the amine groups. When the tolaasin peptide was titrated, its titration curve indicated the presence of titratable amine(s) at pH ranges from 7.0 to 9.6. When the pH-dependence of tolaasin-induced hemolysis was measured at various pHs, hemolysis was more efficient at alkaline pHs. In order to measure the membrane binding activity of tolaasin at different pHs, RBCs were incubated with tolaasin molecules for short time periods and washed out with fresh buffer. Because of the tolaasin binding during the preincubation period, fast hemolyses were observed at pH 8 or higher. These results imply that non-charged or less positively charged states of tolaasin molecules easily bind to membrane and show high hemolytic activity.

• BMB Reports
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• v.29 no.6
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• pp.519-524
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• 1996

Peptidylprolyl cis-trans isomerase (PPlase) catalyzes the cis-trans isomerization of prolyl peptide and facilitates the folding of cellular proteins and peptides. PPlase consists of two distinct immunophilins, each specifically binding to the immunosupressive drug cyclosporin A (CsA) or FK506, respectively. A PPlase was isolated and partially purified from porcine spleen. The molecular weight of porcine spleen PPlase was determined to be ~14,000 on the basis of SDS-PAGE. The purified enzyme was strongly inhibited by FK506, but not by CsA. The inhibition constant and the true concentration of enzyme preparations were determined by active site titration using the tight binding inhibitor FK506: $K_{i}=18.7$ nM and $E_{t}=172$ nM. The equilibrium ratio of conformer. [cis]/[trans], of prolyl peptide substrates (N-Suc-Ala-Xaa-Pro-Phe-p-NA) in anhydrous trifluoroethanol/LiCl solvent system varied from 0.24 to 0.85 depending on the nature of Xaa. Overall. in this solvent-salt system, the populations of the cis conformer of substrates in equilibrium are higher than in an aqueous solution so that the substantial error caused by high background absorption can be reduced. The reactivities of porcine spleen PPlase are shown to be highly sensitive to changes in the structure of substrates. Thus, $k_{cat}/K_m$ value for the most reactive substrate (Xaa Leu) is $4.007+10^{6}M^{1}s^{1}$ and, is 2,636 fold higher than that for the least reactive peptide substrate tested, Xaa=Glu.

• Journal of Radiation Industry
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• v.7 no.2_3
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• pp.191-200
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• 2013

In this study, a novel bombesin (BBN) analogues, DOTA-Ala($SO_3H$)-4 aminobenzoyl-Gln-Trp-Ala-Val-Gly-His-Leu-Met-$NH_2$ (DOTA-sBBN) and DOTA-Lys(glucose)-4 aminobenzoyl-Gln-Trp-Ala-Val-Gly-His-Leu-Met-$NH_2$ (DOTA-gluBBN), were synthesized and radiolabeled, and their binding affinities were evaluated. Peptides were prepared by a solid phase synthesis method and their purities were over 98%. DOTA is the chelating agent for $^{177}Lu$-labeling, and the DOTA-conjugated peptides were radiolabeled with $^{177}Lu$ by a high radiolabeling yield (>98%). The Log P values of DOTA-sBBN and DOTA-gluBBN were -2.20 and -2.79, respectively. 50.41% of $^{177}Lu$-DOTA-sBBN and 72.97% of $^{177}Lu$-DOTA-gluBBN were left undegraded by the serum incubation at $37^{\circ}C$ for 48 hr. A competitive displacement of $^{125}I-[Tyr^4]$-BBN on the PC-3 human prostate carcinoma cells revealed that 50% inhibitory concentration ($IC_{50}$) were 1.46 nM of DOTA-sBBN and 4.67 nM of DOTA-gluBBN indicating a highly nanomolar binding affinity for GRPR. Therefore, it is concluded that $^{177}Lu$-DOTA-sBBN and $^{177}Lu$-DOTA-gluBBN can be potential candidates as a targeting modality for the Gastrin-releasing peptide receptor (GRPR)-over-expressing tumors, and further studies to evaluate their biological and pharmacological characteristics are needed.

• The Korean Journal of Zoology
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• v.38 no.4
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• pp.523-530
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• 1995

Specific affinity binding sites for atrial natriuretic peptide (ANP) were Investigated in the pig ovarian tissues by in vitro autoradiographic techniques. In the pig ovary, the highest binding sites for 12514abeiled rANP(l~28) were localized in the granulosa cell layer of the forncles. The binding sies on theca layer of the ovarian follicles were mainly localized in the external layer, but none was observed In the Internal layer. In the corpus luteum, the binding site was not observed. The specific bindings of 200 pM of l2Sl4abelled rANP(l~28) to granulosa and theca externa layers were reversed completely by excess concentration (1 ~4) of unlabelled rANP(l~28) but not by 10 ~ of unrelated peptides, human angiotensin II and arginine vasopressin. The binding was also displaced by 1 ~ of desiGIn18, Ser19, Gly2O, leu21, Gly22I ANP(4~2g) (C- ANF) as a spedfic ligand of the ANP clearance receptor. Therefore these results indicate ~hat the biological and the clearance ANP receptors exist in the theca externa and granulosa layer of the pig ovary, and suggest that the ANP receptors may be related with the regulatory lundion of the ovarian follicular development including oocyte maturation.

• Journal of the East Asian Society of Dietary Life
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• v.20 no.5
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• pp.680-686
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• 2010

Silk sericin protein was hydrolyzed by seven proteolytic enzymes in order to examine the effectiveness of the hydrolysates in binding calcium. The amino acid nitrogen content of hydrolysates from Flavourzyme was higher than that for other enzymes, and its calcium binding capacity showed a dose-dependent increase. We examined the effects of calcium binding peptide from sericin hydolysates on the bioavailability of Ca-deficient rats. Three-week-old male rats were fed an Ca-deficient diet for three weeks. Rats were divided into four groups (DD: non-treated group on calcium deficient diet; DD+MC: milk-calcium treated group; DD+OC: organic calcium made using sericin hydolysates; and DD+IC: inorganic calcium ($CaCl_2$). After oral administration of calcium supplements for one week, the calcium content of the serum and liver were significantly higher in DD+OC ($101.7{\mu}g$/mL and $49.3{\mu}g$/mL) and DD+MC ($83.6{\mu}g$/mL and $42.8{\mu}g$/mL) than DD ($86.3{\mu}g$/mL and $43.4{\mu}g$/mL). The alkaline phosphatase (ALP) content in the treated groups was significantly lower than DD, but no significant difference among groups was shown. Aspartate aminotransferase (AST) levels did not show any significant difference between groups. Alanine aminotransferase (ALT) levels were significantly reduced compared to the DD group. In conclusion, binding calcium to peptides from sericin hydrolysates seems to improve its bioavailability, and to hasten the cure of calcium deficiency in experimental rats.

• Korean Journal of Plant Tissue Culture
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• v.28 no.4
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• pp.201-204
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• 2001

Acyl-CoA binding proteins (ACBP) are small highly-conserved cytosolic proteins that bind long-chain acyl-CoAs. A cDNA encoding ACBP was identified from cDNA library constructed from hairy root poly $A^{＋}$ RNA in expressed sequence tags (EST) analysis. The cDNA clone was 453 bp long and carried an open reading frame of 264 bp (10 kDa). The ginseng ACBP amino acid sequence was compared with other reported plant ACBPs using the CLUSTALW. Ginseng ACBP is 89%, 81%, 80%, and 73% identical with ACBP from castor bean, lilly, Digitalis and Arabidopsis, respectively. However, ginseng ACBP is 5 amino acids smaller than Arabidopsis and rape seed ACBPs. Also there is no any known signal peptide sequence in ginseng ACBP.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.10
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• pp.1459-1464
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• 2004

The purpose of this research was to investigate the potential use of cheese whey protein (CWP), a cheese by-product. The physiological activity of calcium-binding peptides in CWP may be used as a food additive that prevents bone disorders. This research also examined the characteristics of calcium-binding peptides. After the CWP was heat treated, it was hydrolyzed by trypsin. Then calcium-binding peptides were separated and purified by ion-exchange chromatography and reverse phase HPLC, respectively. To examine the characteristics of the purified calcium-binding peptides, amino acid composition and amino acid sequence were analyzed. Calcium-binding peptides with a small molecular weight of about 1.4 to 3.4 kDa were identified in the fraction that was flowed out from 0.25 M NaCl step gradient by ion-exchange chromatography of tryptic hydrolysates. The results of the amino acid analysis revealed that glutamic acid in a calcium-binding site took up most part of the amino acids including a quantity of proline, leucine and lysine. The amino acid sequence of calcium-binding peptides showed Phe-Leu-Asp-Asp-Asp-Leu-Thr-Asp and Ile-Leu-Asp-Lys from $\alpha$-LA and Ile-Pro-Ala-Val-Phe-Lys and Val-Tyr-Val-Glu-Glu-Leu-Lys from ${\beta}$-LG.

• Journal of Microbiology and Biotechnology
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• v.28 no.5
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• pp.671-678
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• 2018

Papiliocin, isolated from the swallowtail butterfly (Papilio xuthus), is an antimicrobial peptide with high selectivity against gram-negative bacteria. We previously showed that the N-terminal helix of papiliocin (PapN) plays a key role in the antibacterial and anti-inflammatory activity of papiliocin. In this study, we measured the selectivity of PapN against multidrug-resistant gram-negative bacteria, as well as its anti-inflammatory activity. Interactions between Trp2 of PapN and lipopolysaccharide (LPS), which is a major component of the outer membrane of gram-negative bacteria, were studied using the Trp fluorescence blue shift and quenching in LPS micelles. Furthermore, using circular dichroism, we investigated the interactions between PapN and LPS, showing that LPS plays critical roles in peptide folding. Our results demonstrated that Trp2 in PapN was buried deep in the negatively charged LPS, and Trp2 induced the ${\alpha}$-helical structure of PapN. Importantly, docking studies determined that predominant electrostatic interactions of positively charged arginine residues in PapN with phosphate head groups of LPS were key factors for binding. Similarly, hydrophobic interactions by aromatic residues of PapN with fatty acid chains in LPS were also significant for binding. These results may facilitate the development of peptide antibiotics with anti-inflammatory activity.