• BMB Reports
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• v.37 no.4
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• pp.429-438
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• 2004

Complementary DNAs encoding $\alpha$-amylases (Amyl I, Amyl III) and glucoamylase (GA I) were cloned from Aspergillus awamori KT-11 and their nucleotide sequences were determined. The sequence of Amyl III that was a raw starch digesting $\alpha$-amylase was found to consist of a 1,902 bp open reading frame encoding 634 amino acids. The signal peptide of the enzyme was composed of 21 amino acids. On the other hand, the sequence of Amyl I, which cannot act on raw starch, consisted of a 1,500 bp ORF encoding 499 amino acids. The signal peptide of the enzyme was composed of 21 amino acids. The sequence of GA I consisted of a 1,920 bp ORF that encoded 639 amino acids. The signal peptide was composed of 24 amino acids. The amino acid sequence of Amyl III from the N-terminus to the amino acid number 499 showed 63.3% homology with Amyl I. However, the amino acid sequence from the amino acid number 501 to C-terminus, including the raw-starch-affinity site and the TS region rich in threonine and serine, showed 66.9% homology with GA I.

• Journal of Veterinary Clinics
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• v.21 no.3
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• pp.253-258
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• 2004

DNA double-strand break (DSB) is a serious treat for the cells including mutations, chromosome rearrangements, and even cell death if not repaired or misrepaired. Ku heterodimer regulatory DNA binding subunits (Ku70/Ku80) bound to double strand DNA breaks are able to interact with 470-kDa DNA-dependent protein kinase catalytic subunit (DNA-PKcs), and the interaction is essential for DNA-dependent protein kinase (DNA-PK) activity. The Ku80 mutants were designed to bind Ku70 but not DNA end binding activity and the peptides were treated in breast cancer cells for co-therapy strategy to see whether the targeted inhibition of DNA-dependent protein kinase (DNA-PK) activity sensitized breast cancer cells to ionizing irradiation or chemotherapy drug to develop a treatment of breast tumors by targeting proteins involved in damage-signaling pathway and/or DNA repair. We designed domains of Ku80 mutants, 26 residues of amino acids (HN-26) as a control peptide or 38 (HNI-38) residues of amino acids which contain domains of the membrane-translocation hydrophobic signal sequence and the nuclear localization sequence, but HNI-38 has additional twelve residues of peptide inhibitor region. We observed that the synthesized peptide (HNI-38) prevented DNA-PKcs from binding to Ku70/Ku80, resulting in inactivation of DNA-PK complex activity in breast cancer cells (MDA-465 and MDA-468). Consequently, the peptide treated cells exhibited poor to no DNA repair, and became highly sensitive to irradiation or chemotherapy drugs. The growth of breast cancer cells was also inhibited. These results demonstrate the possibility of synthetic peptide to apply breast cancer therapy to induce apoptosis of cancer cells.

• KSBB Journal
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• v.22 no.4
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• pp.260-264
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• 2007

Peptides are frequently studied as candidates for new drug development. Recently, synthesized peptide library is screened for a certain functionality on a microarray biochip format. In this study, in order to replace the conventional cellulose membrane with glass for a microarray chip substrate for peptide library screening, we modified the glass surface from amines to thiols and covalently immobilized the peptides. Using trypsin-FITC (fluorescein isothiocyanate) conjugate that could specifically bind to a trypsin binding domain consisting of a 7-amino acid peptide, we checked the degree of surface modification. Because of the relatively lower hydrophilicity and reduced surface roughness, the conjugation reaction to the glass required a longer reaction time and a higher temperature. It took approximately 12 hr for the reaction to be completed. From the fluorescence signal intensity, we could differentiate between the target and the control peptides. This difference was confirmed by a separate experiment using QCM. Furthermore, a smaller volume and higher concentration of a spot showed a higher fluorescence intensity. These data would provide the basic conditions for the development of microarray peptide biochips.

• Journal of Life Science
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• v.12 no.4
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• pp.477-482
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• 2002

As a biological model system for the production of an active antibacterial peptide, we have attempted the expression and secretion of insect defensin in Saccharomyces cerevisiae. Nucleotide sequences encoding mature defensin composed of 40 amino acids were fused in frame with promoter and signal sequence of Saccharomyces diastaticus glucoamylase, and mating factor $\alpha$ l[MF $\alpha$1] prosequence. The host strain, S. cerevisiae 2805 was transformed with the resulting plasmid, pSMFll The secretion of functional defensin was confirmed by growth inhibition zone assay using Micrococcus luteus as a test organism. Insect defensin was secreted to the culture supernatant in biologically active form by glucoamylase signal sequence and mating factor $\alpha$1 prosequence. Most of antibacterial activity was detected in the culture supernatant. Defensin was also active against Staphylococcus aureus and Listeria monocytogenes.

• Journal of Microbiology and Biotechnology
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• v.18 no.7
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• pp.1245-1251
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• 2008

Oxalate decarboxylases (OXDCs) (E.C. 4.1.1.2) are enzymes catalyzing the conversion of oxalate to formate and $CO_2$. The OXDCs found in fungi and bacteria belong to a functionally diverse protein superfamily known as the cupins. Fungi-originated OXDCs are secretory enzymes. However, most bacterial OXDCs are localized in the cytosol, and may be involved in energy metabolism. In Agrobacterium tumefaciens C58, a locus for a putative oxalate decarboxylase is present. In the study reported here, an enzyme was overexpressed in Escherichia coli and showed oxalate decarboxylase activity. Computational analysis revealed the A. tumefaciens C58 OXDC contains a signal peptide mediating translocation of the enzyme into the periplasm that was supported by expression of signal-peptideless and full-length versions of the enzyme in A. tumefaciens C58. Further site-directed mutagenesis experiment demonstrated that the A. tumefaciens C58 OXDC is most likely translocated by a twin-arginine translocation (TAT) system.

• BMB Reports
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• v.39 no.3
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• pp.278-283
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• 2006

Defensins are small cysteine rich peptides with a molecular mass of 5-10 kDa and some of them exhibit potent antifungal activity. We have cloned the coding region of a cDNA of 225 bp cysteine rich defensin, named as Tfgd1, from the legume Trigonella foenum-graecum. The amino acid sequence deduced from the coding region comprised 74 amino acids, of which the N-terminal 27 amino acids constituted the signal peptide and the mature peptide comprised 47 amino acids. The protein is characterized by the presence of eight cysteine resisdues, conserved in the various plant defensins forming four disulphide bridges, which stabilize the mature peptide. The recombinant protein expressed in E coli exhibited antifungal activity against the broad host range fungus, Rhizoctonia solani and the peanut leaf spot fungus, Phaeoisariopsis personata.

• BMB Reports
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• v.31 no.5
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• pp.427-431
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• 1998

In the previous report (Choi et al., 1997), the angiogenin binding peptides identified from a phage-peptide library were analyzed by using the fusion proteins composed of the Escherichia coli maltose binding protein and its corresponding peptides. However, it was difficult to obtain a sufficient amount of the fusion proteins required for further analysis because of the low expression level. We now report a high level expression of the fusion protein and analysis of its anti-angiogenin activity. The use of strong T7 promoter and removal of signal sequence allowed about a 20-fold increase in the expression efficiency of the fusion protein. We were able to obtain about 10 mg of purified fusion protein from one liter of culture. The purified fusion protein showed angiogenin-specific affinity and inhibited the binding of biotinylated actin to human angiogenin at $IC_{50}$ of 0.6 mM. Its anti-angiogenin activity was also revealed by the chorioallantoic membrane assay.

• Journal of Microbiology and Biotechnology
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• v.22 no.11
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• pp.1588-1590
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• 2012

We compared the mRNA expression profile of the Harmonia axyridis larvae that were either untreated or treated with LPS. The extracted mRNAs were subjected to ACP RT-PCR analysis using a combination of arbitrary primers and oligo (dT) primer. Among the 47 DEGs differentially expressed, we identified a cDNA showing homology with defensin-like antibacterial peptide. The cDNA showed a putative 32-residue signal sequence and a 50-residue mature peptide named harmoniasin. We also investigated the antibacterial activity of the harmoniasin analog, which exhibited potent antibacterial activities against Gramnegative and -positive bacteria strains and it also evidenced no hemolytic activity.

• The Korean Journal of Physiology
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• v.24 no.1
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• pp.131-144
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• 1990

It is well known that the atrial natriuretic peptide (ANP) has a prepro-hormone of 151 amino-acids which loses their hydrophobic signal peptide to form 126 amino acid prohormone. The whole prohormone is released and then cleaved by proteases into more than one circulating forms. Recently, Winters et al. (1988a, b) reported that high concentrations of N-terminal fragments of prepro-ANP $(26{\sim}55),\;(56{\sim}92)\;and\;(104{\sim}123)$ were detected in human plasma. However, their physiological roles have not been established. The present study was conducted to determine whether the N-terminal fragments of pro-ANP have any effect on the renal function and to compare the effect with those of G-terminal fragments of pro-ANP The results indicate that intrarenal arterial infusions of prepro-ANP $(26{\sim}41),\;(26{\sim}55),\;(56{\sim}92)\;and\;(104{\sim}123)$ induced no significant changes in renal function. Whereas ${\alpha}-human$ ANP $(prepro-ANP,\;124{\sim}151)$ and pro-ANP caused a significant increase in urine volume, renal plasma flow, glomerular filtration rate, urinary excretions of sodium, chloride and potassium, and fractional excretion of sodium. These results suggest that the N-terminal fragments of pro-ANP are ineffective, while the C-terminal fragments retain the natriuretic and diuretic activities.

• Korean Journal of Microbiology
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• v.24 no.3
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• pp.236-242
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• 1986

The nucleotide sequence of the genetic control site of Bacillus subtilis gene for $(1-4)-{\beta}-D-glucan$ endoglucanase (cellulase) was determined according to the procedures of the dideoxy chain termination method(Sanger et. al., 1977). The deduced amino acid sequence of this enzyme has a hydrophobic signal peptide at the $NH_2$ terminus similar to those found in fifteen other extracellualr enzymes from Bacillus species. This is followed by a sequence resembling the Bacillus ribosome binding site 14 nucleotide before the first codon of the gene. The presumptive promoter sequence was located 92 base pairs upstream fromthe initiation codon. The homology region in signal sequences was striking when comparing all the signal sequences of sixteen extracellular enzymes from Bacillus species so far compiled.