• Mass Spectrometry Letters
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• v.6 no.3
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• pp.80-84
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• 2015

Here, we demonstrate the use of MALDI-TOF as a fast and simple analytical approach to evaluate the DNA-binding capability of various peptides. Specifically, by varying the amino acid sequence of the peptides consisting of lysine (K) and tryptophan (W), we identified peptides with strong DNA-binding capabilities using MALDI-TOF. Mass spectrometric analysis reveals an interesting novel finding that lysine residues show sequence selective preference, which used to be considered as mediator of electrostatic interactions with DNA phosphate backbones. Moreover, tryptophan residues show higher affinity to DNA than lysine residues. Since there are numerous possible combinations to make peptide oligomers, it is valuable to introduce a simple and reliable analytical approach in order to quickly identify DNA-binding peptides.

• BMB Reports
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• v.29 no.6
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• pp.545-548
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• 1996

CA(1-8)ME(1-12), the CA-ME hybrid peptide of the amino terminal segments of cecropin A (CA) and melittin (ME), has been reported to have a broad spectrum and improved potency without a hemolytic property. In order to obtain new synthetic peptides with powerful antibacterial activity without hemolytic activity, several hybrid peptides were designed from the sequences of CA, ME, magainin 2, bombinin and lactoferricin. All hybrid peptides were constructed to form an amphipathically basic-flexible-hydrophobic structure and synthesized by the solid phase method. Their hemolytic activities against human red blood cells and antibacterial activities against both Gram-positive and Gram-negative bacteria were detennined. CA(1-8)MA(1-12), CA(1-8)BO(1-12), MA(10-17)ME(1-12) and LF(20-29)ME(1-12) showed comparable activities with broad spectra against both Gram-positive and Gram-negative bacteria relative to CA(1-8)ME(1-12) but without hemolytic properties. These hybrid peptides, therefore, could be useful as model peptides to design a novel peptide with improved antibacterial activity and study on structure-activity relationships of antimicrobial peptides.

• Korean Journal of Plant Resources
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• v.20 no.6
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• pp.518-523
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• 2007

Lunasin is small subunit peptide of coded from Gm2S-1 gene in soybean. It has been previously demonstrated that lunasin is a novel and promising cancer preventive peptide. Lunasin peptide is found only in the seed and not other tissues. And lunasin peptide starts to appear at 5 weeks after flowering and remains in the mature seed. We report here firstly lunasin peptide identified from soybean callus induced by the tissue culture and demonstrate its anticancer properties. The lunasin was identified and purified from soybean callus aged for 6 months. The callus lunasin($1{\mu}M$) inhibited the acetylation of histone H3 and H4 by 58.8% and 56.5%, respectively. And it fully inhibited foci formation compared to the values of the positive control(no lunasin) and negative control(no MCA). Purified lunasin was able to internalize into the cell and localized in the nucleus.

• Journal of Microbiology and Biotechnology
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• v.14 no.6
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• pp.1318-1323
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• 2004

This study describes the purification and characterization of a novel antihypertensive angiotensin 1­converting enzyme (ACE) inhibitory peptide from Saccharomyces cerevisiae. Maximal production of the ACE inhibitor from Saccharomyces cerevisiae was obtained from 24 h of cultivation at $30^{\circ}C$ and its ACE inhibitory activity was increased by about 1.5 times after treatment of the cell-free extract with pepsin. After the purification of ACE inhibitory peptides with ultrafiltration, Sephadex G-25 column chromatography, and reverse-phase HPLC, an active fraction with an $IC_{50}$ of 0.07 mg and $3.5\%$ yield was obtained. The purified peptide was a novel decapeptide, showing very low similarity to other ACE inhibitory peptide sequences, and its amino acid sequence was Tyr-Asp-Gly-Gly-Val-Phe-Arg-Val-Tyr-Thr. The purified inhibitor competitively inhibited ACE and also showed a clear antihypertensive effect in spontaneously hypertensive rats (SHR) at a dosage of 1 mg/kg body weight.

• Journal of Microbiology and Biotechnology
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• v.19 no.8
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• pp.792-802
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• 2009

Antimicrobial peptides (AMPs) are considered to be a promising alternative to conventional antibiotics for future generations. We identified four novel hexapeptides with antimicrobial activity: KCM11 (TWWRWW-$NH_2$), KCM12 (KWRWlW-$NH_2$), KCM21 (KWWWRW-$NH_2$), and KRS22 (WRWFIH-$NH_2$), through positional scanning of a synthetic peptide combinatorial library (PS-SCL). The ability of these peptides to inhibit the growth of a variety of bacteria and unicellular fungi was evaluated. KCM11 and KRS22 preferentially inhibited the normal growth of fungal strains, whereas KCM12 and KCM21 were more active against bacterial strains. Bactericidal activity was addressed in a clear zone assay against phytopathogenic bacteria, including Pectobacterium spp., Xanthomonas spp., Pseudomonas spp., etc. KCM21 showed the highest activity and was effective against a wide range of target organisms. Application of KCM21 with inoculation of Pectobacterium carotovorum subsp. carotovorum on detached cabbage leaves resulted in an immune phenotype or a significant reduction in symptom development, depending on the peptide concentration. Cytotoxicity of the four hexapeptides was evaluated in mouse and human epithelial cell lines using an MTT test. The results revealed a lack of cytotoxic effects.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.557-557
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• 2012

Silicatein-${\alpha}$, the enzyme extracted from silica spicules in glass sponges, has been studied extensively in the way of chemistry from 1999, in which the pioneering work by Morse, D. E. - the discovery of the enzymatic hydrolysis in Silicatein-${\alpha}$ - was published. Since its reaction conditions are physiologically favored, synthesis of various materials, such as gallium oxide, zirconium oxide, and silicon oxide, was achieved without any hazardous wastes. Although some groups synthesized oxide films and particles, they have not achieved yet controlled morphogenesis in the reaction conditions mentioned above. With the knowledge of catalytic triad involved in hydrolysis of silicone alkoxide and oligomerization of silicic acid, we designed the novel peptide amphiphiles to not only form self-assembled structure, but also display similar activities to silicatein-${\alpha}$. Designed templates were able to self-assemble into left-handed helices for the peptide amphiphiles with L-form amino acid, catalyzing polycondensation of silicic acids onto the surface of them. It led to the formation of silica helices with 30-50 nm diameters. These results were characterized by various techniques, including SEM, TEM, and STEM. Given the situation that nano-bio-technology, the bio-applicable technology in nanometer scale, has been attracting considerable attention; this result could be applied to the latest applications in biotechnology, such as biosensors, lab-on-a-chip, biocompatible nanodevices.

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3760-3764
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• 2010

We screened 10,000 heterocyclic small molecules and identified a novel hit core skeleton of 3-(8-chloro-6-(trifluoromethyl) imidazo[1,2-a]pyridine-2-yl)phenyl acetate derivatives. It has been selected as a potential glucagon-like peptide 1 receptor (GLP-1R) activator and demonstrated its effects in increasing GLP-1 secretion, and thereby increasing the glucose responsiveness in both in vitro and pharmacology analyses. Further studies are currently underway to optimize the potency and selectivity of 3-(8-chloro-6-(trifluoromethyl)imidazo[1,2-a]pyridine-2-yl)phenyl acetate derivatives (hit compounds 2 and 8), and address their in vivo efficacy and therapeutic potential. These molecules may serve as useful evidence showing that compounds with a 3-(8-chloro-6-(trifluoromethyl)imidazo[1,2-a]pyridine-2-yl)phenyl acetate moiety are selective GLP-1R agonists, and have potential as anti-diabetic treatment agents.

• Bulletin of the Korean Chemical Society
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• v.29 no.2
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• pp.323-327
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• 2008

A focused library of pyrazole-based compounds was constructed towards novel transcription factor inhibitors. Complementary hydrogen bonding interaction with b-sheet peptide structures was the basis for the design of 5-amino-3-pyrazole carboxamide scaffold. From the preliminary inhibition assay against several transcription factors, compounds 7e and 8g were identified as novel lead compounds against HIF-1a and NF-AT transcription factors, respectively.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.175.2-175.2
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• 2003

Inhibition of the protein-modifying enzyme farnesyltransferase is considered as a major emerging strategy in cancer therapy because of the involvement of farnesylated proteins in oncogensis. We studied the structure-activity relationship of a novel class of CAAX-peptidomimetic farnesyltransferase inhibitors based on the benzophenone scaffold. FlexX docking of inhibitors confirmed reasonable fit of the molecule into the peptide binding site of farnesyltransferase. We also performed a virtual screening with LeadQuest chemical library databases to idenfity novel inhibitors of farnesyltransferase. (omitted)

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.232.1-232.1
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• 2003

Bradykinin is an autocoid related to acute and chronic pain and inflammation. The non-peptide bradykinin antagonists are of interest as novel anti-inflammatory therapeutics and some active compounds such as FR 173657, LF 16-0687, and bradyzide were reported very recently. In our search for the new bradykinin antagonists, we designed to synthesize the analogues of FR173657 with two to three amide bonds and lipophilic ring system in each molecule. (omitted)