• Microbiology and Biotechnology Letters
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• v.28 no.4
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• pp.195-201
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• 2000

Glucoamylase of Saccharomyces diastaticus is produced as a large precursor composed of signal peptide (21 amino acid residues), Thr and Ser-rich region and functional glucoamylase. To evaluate the utility of the glucoamylase signal peptide (GSP) for the secretion of foreign proteins, four types of GSP mutants (ml : Pro-18 longrightarrowLeu-18, m2 : Tyr-13 longrightarrowLeu, m3 : Ser-9longrightarrowLeu-9, m4 : Asn-5 longrightarrowPro-5) were constructed and secretion efficiency of each mutant was compared with that of native GSP by the expression and secretion of Bacillus subtilis CMCase under the control of GAP in N-terminal domain and hydrophobic domain. n mutant 4, a polar amino acid was replaced by a helix - breaking Pro residue. CMCase activity assay and Western blot analysis revealed that CMCase secretion by GSP mutants replaced by Leu were increased compared with native GSP. In the case of m2 and m3, the substitution of Leu for Tyr-13 and Ser-9 in the hydrophobic region resulted in a twofold increase in the extracellular CMCase activity.

• Journal of Microbiology and Biotechnology
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• v.30 no.9
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• pp.1387-1394
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• 2020

Clam worms (Marphysa sanguinea) are a rich source of bioactive components such as the antibacterial peptide, perinerin. In the present study, we explored the physiological activities of a novel NCWPFQGVPLGFQAPP peptide (NCW peptide), which was purified from clam worm extract through high-performance liquid chromatography. Tandem mass spectrometry (MS/MS) revealed that NCW was a new peptide with a molecular weight of 1757.86 kDa. Moreover, NCW peptide exhibited significant antioxidant effects, causing a 50% inhibition of DPPH radical at a concentration of 20 μM without showing any cytotoxicity. These were associated with a reduction in the activity of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) in LPS-stimulated RAW264. 7 cells. Furthermore, NCW peptide exhibited anti-inflammatory effects in LPS-stimulated RAW264.7 macrophages via inhibition of the abnormal production of pro-inflammatory cytokines including nitric oxide (NO), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2). These anti-inflammatory effects of NCW peptide were associated with the inhibition of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α). Our results therefore suggest that this novel NCW peptide with antioxidant and anti-inflammatory effects could be a good therapeutic agent against inflammation-related diseases.

• BMB Reports
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• v.44 no.10
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• pp.669-673
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• 2011

Human methionine sulfoxide reductase B3A (hMsrB3A) is an endoplasmic reticulum (ER) reductase that catalyzes the stereospecific reduction of methionine-R-sulfoxide to methionine in proteins. In this work, we identified an antimicrobial peptide from hMsrB3A protein. The N-terminal ER-targeting signal peptide (amino acids 1-31) conferred an antimicrobial effect in Escherichia coli cells. Sequence and structural analyses showed that the overall positively charged ER signal peptide had an Argand Pro-rich region and a potential hydrophobic ${\alpha}$-helical segment that contains 4 cysteine residues. The potential ${\alpha}$-helical region was essential for the antimicrobial activity within E. coli cells. A synthetic peptide, comprised of 2-26 amino acids of the signal peptide, was effective at killing Gram-negative E. coli, Klebsiella pneumoniae, and Salmonella paratyphi, but had no bactericidal activity against Gram-positive Staphylococcus aureus.

• Bulletin of the Korean Chemical Society
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• v.31 no.1
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• pp.209-212
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• 2010

• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.409-413
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• 2012

Indolicidin (ID) is a 13-residue Trp-rich antimicrobial peptide (AMP) isolated from bovine neutrophils. In addition to having a high antimicrobial potency, it is also toxic to mammalian cells. To develop novel ID-derived AMPs with shorter lengths and enhanced prokaryotic selectivities (meaning potent antimicrobial activity against bacterial cells without toxicity against mammalian cells) over the parental ID, several ID analogs were designed and synthesized. Finally, 10-residue ID analogs (SI, SI-PA, SI-WF and SI-WL) with much higher prokaryotic selectivity than the parental ID were developed. Our results suggest that the hydrophobic and aromatic amino acids at the central position of the analog SI with the highest prokaryotic selectivity are important for potent antimicrobial activity, but two Pro residues do not affect antimicrobial activity. The order of prokaryotic selectivity for ID and its designed analogs was SI > SI-PA > SI-WF > SI-WL > ID > SI-WA. Taken together, our designed short ID analogs could be developed as therapeutic agents for treating bacterial infections.

• Journal of Microbiology and Biotechnology
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• v.28 no.5
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• pp.707-717
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• 2018

Leukocytes are reportedly the first line of the innate immune defense and essential for the control of common bacterial infections. Therefore, in this work, the antibacterial activity of crocodile leukocyte extract against Propionibacterium acnes was evaluated, and we also characterized the related activity of skin infection. The leukocyte extract showed the minimum inhibitory concentration to be $100{\mu}g/ml$ to P. acnes. SEM imaging demonstrated that the leukocyte extract adversely affected P. acnes cell permeability in a concentration-dependent manner. Furthermore, the crocodile leukocyte extract could significantly reduce proinflammatory markers and decrease inflammatory signs in infected mouse ears. The crude leukocyte extract was further purified using FPLC and RP-HPLC. The resulting fraction F5 was indicated as the anti-acne peptide-containing fraction. The molecular mass of the peptide contained in F5 was calculated to be 4,790.5 Da. N-Terminal sequencing revealed the amino acid sequence as GPEPVPAIYQ, which displays similarities to immunoglobulin A and leucine-rich repeat neuronal protein. This is the first reported amino acid sequence of a crocodile leukocyte extract that possesses anti-acne activity. To attempt to use it in a prototype cosmetic, an anti-acne gel containing crude crocodile leukocyte extract was formulated, resulting in seven gel formulations (G1, G2, G3, G4, G5, G6, and G7). The formulations G5, G6, and G7 exhibited 2-fold higher anti-acne activity than G1-G4. Investigation of accelerating stability studies of anti-acne gel formulations G5, G6, and G7 demonstrated that a low storage temperature ($4^{\circ}C$) is suitable for maintaining the physical properties and biological activity of the anti-acne gel products.

• Korean Journal of Microbiology
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• v.45 no.1
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• pp.54-57
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• 2009

Fermented soybean, Chungkookjang has diverse bioactive compounds including antioxidants and peptides. Ethanol extract from Chungkookjang exhibited absorbance of 0.55 at 285 nm, where amino acids and peptides containing phenol are known to exist. Antioxidant activity of Chungkookjang was determined using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. With increasing concentrations of ethanol extracts, their antioxidant activities increased. Blood pressure was determined every two hours after taking raw Chungkookjang which does not contain salts. In 6 h, systolic blood pressure dropped by 14 mmHg, and diastolic one dropped by 8 mmHg, which was statistically significant. Daidzein, antioxidants, angiotensin I-converting enzyme (ACE) inhibitor such as Lys-Pro which are rich in Chungkookjang might contribute to the reduction of blood pressure.