• Journal of Life Science
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• v.26 no.1
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• pp.17-22
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• 2016

Ethanol is a very valuable material, however, it is also a source of stress, as the accumulation of ethanol in a medium inhibits cell viability and decreases productivity of the target product. Therefore, the ethanol tolerance of yeast, which is closely related to ethanol productivity, is an important factor in industrial ethanol production. In this study, the YDJ1 and PEP5 genes were selected as target genes for elucidating ethanol-tolerant mechanisms by analyzing the expression regulation of these genes. The pA-YDJ1 and pA-PEP5 plasmids containing YDJ1 and PEP5 genes under an ADH1 promoter, respectively, were constructed and transformed into BY4742 (host strain), BY4742△ydj1, and BY4742△pep5 strains. The ethanol tolerance in the BY4742△ydj1/ pA-YDJ1 and BY4742△pep5/pA-PEP5 transformants was restored by overexpression of the YDJ1 and PEP5 genes to the host strain level. The YDJ1 and PEP5 genes were also introduced into the double gene disruptant (BY4742△ydj1△pep5) to investigate the expression regulation of the YDJ1 and PEP5 genes. The simultaneous overexpression of the YDJ1 and PEP5 genes restored ethanol tolerance to the 90% level of the BY4742 strain under 8% ethanol stress. The YDJ1 gene induced more overexpression of the PEP5 gene in the BY4742△ydj1 △pep5/pA-YDJ1, pA-PEP5 strain, suggesting that the YDJ1 gene partially regulates the expression of the PEP5 gene as an upstream regulator.

• BMB Reports
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• v.44 no.4
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• pp.256-261
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• 2011

PEP-1 peptide has been used for transduction of native protein into mammalian cells. This work describes the findings that the fusion of PEP-1 to target proteins led to protein truncation likely in a non-protein-specific manner. Approximately 75% of PEP-1-MsrA fusion protein was truncated in the N-terminal region of MsrA between Lys-27 and Val-28 during expression in Escherichia coli and purification. This large protein truncation was also observed in another PEP-1 fused protein, PEP-1-MsrB2, in the N-terminal region of MsrB2. The full-length PEP-1-MsrA protein was rapidly transduced into keratinocyte cells within 15 min. The transduced PEP-1-MsrA was functionally active and could protect skin cells against oxidative stress- and ultraviolet radiation-induced cell death. Collectively, our data demonstrated the protective roles of MsrA in skin cells and, moreover, may raise a concern of protein truncation caused by fusion of PEP-1 about the general use of this peptide for protein transduction.

• Journal of Microbiology and Biotechnology
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• v.33 no.3
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• pp.371-377
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• 2023

In this study, a pepA gene encoding glutamyl (aspartyl)-specific aminopeptidase (PepA; E.C. 3.4.11.7) was cloned from Tetragenococcus halophilus CY54. The translated PepA from T. halophilus CY54 showed very low similarities with PepAs from Lactobacillus and Lactococcus genera. The pepA from T. halophilus CY54 was overexpressed in E. coli BL21(DE3) using pET26b(+). The recombinant PepA was purified by using an Ni- NTA column. The size of the recombinant PepA was 39.13 kDa as determined by SDS-PAGE, while its optimum pH and temperature were pH 5.0 and 60℃, respectively. In addition, the PepA was completely inactivated by 1 mM EDTA, indicating its metallopeptidase nature. The Km and Vmax of the PepA were 0.98 ± 0.006 mM and 0.1 ± 0.002 mM/min, respectively, when Glu-pNA was used as the substrate. This is the first report on PepA from Tetragenococcus species.

• Journal of Periodontal and Implant Science
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• v.50 no.3
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• pp.159-170
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• 2020

Purpose: Immunization with Porphyromonas gingivalis heat shock protein 60 (PgHSP60) may have an immunoregulatory effect on atherogenesis. The aim of this study was to determine whether nasal immunization with a PgHSP60 peptide could reduce atherosclerotic plaque formation in apolipoprotein E knockout (ApoE KO) mice. Methods: Seven-week-old male ApoE KO mice were assigned to receive a normal diet, a Western diet, a Western diet and challenge with PgHSP60-derived peptide 14 (Pep14) or peptide 19 (Pep19), or a Western diet and immunization with Pep14 or Pep19 before challenge with Pep14 or Pep19. Results: Atherosclerotic plaques were significantly smaller in mice that received a Western diet with Pep14 nasal immunization than in mice that received a Western diet and no Pep14 immunization with or without Pep14 challenge. An immunoblot profile failed to detect serum reactivity to Pep14 in any of the study groups. Stimulation by either Pep14 or Pep19 strongly promoted the induction of CD4⁺CD25⁺ forkhead box P3 (FoxP3)⁺ human regulatory T cells (Tregs) in vitro. However, the expression of mouse splenic CD4⁺CD25⁺FoxP3⁺ Tregs was lower in the Pep14-immunized mice than in the Pep14-challenged or Pep19-immunized mice. Levels of serum interferon gamma (IFN-γ) and transforming growth factor beta were higher and levels of interleukin (IL) 10 were lower in the Pep14-immunized mice than in the other groups. Induction of CD25^- IL-17⁺ T helper 17 (Th17) cells was attenuated in the Pep14-immunized mice. Conclusions: Nasal immunization with Pep14 may be a mechanism for attenuating atherogenesis by promoting the secretion of IFN-γ and/or suppressing Th17-mediated immunity.

• Journal of Microbiology and Biotechnology
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• v.25 no.10
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• pp.1629-1633
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• 2015

Peptide assimilation in Helicobacter pylori necessitates a coordinated working of the peptide transport systems (PepTs) and aminopeptidase (PepA). We found that H. pylori hydrolyzes two detector peptides, _L-phenylalanyl- _L-3-thiaphenylalanine (PSP) and _L-phenylalanyl- _L-2-sulfanilylglycine (PSG), primarily before intake and excludes their antibacterial effects, whereas Escherichia coli readily transports them with resultant growth inhibition. PSP assimilation by H. pylori was inhibited by aminopeptidase inhibitor bestatin, but not by dialanine or cyanide-m-chlorophenylhydrazone, contrary to that of E. coli. RT- and qRT-PCR analyses showed that H. pylori may express first the PepTs (e.g., DppA and DppB) and then PepA. In addition, western blot analysis of PepA suggested that the bacterium secretes PepA in response to specific inducers.

• Journal of Applied Biological Chemistry
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• v.49 no.3
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• pp.110-113
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• 2006

Prolyl endopeptidase (PEP, EC 3.4.21.26, also referred to as prolyl oligopeptidase) degrades proline containing, biologically active neuropeptides such as vasopressin, substance P and thyrotropin-releasing hormone by cleaving peptide bonds on carboxyl side of prolyl residue within neuropeptides of less than 30 amino acids. Evaluation of PEP levels in postmortem brains of Alzheimer's disease patients revealed significant increases in PEP activity. Therefore, a specific PEP inhibitor can be a good candidate of drug against memory loss. Upon our examination for PEP inhibitory activity from micronutrients, ascorbic acid (vitamin C) showed small but significant PEP inhibition (13% PEP inhibition at $8{\mu}g{\cdot}ml^{-1}$). Palmitic acid showed almost no PEP inhibition. However, 6-O-palmitoyl ascorbic acid ($\underline{1}$) showed 70% PEP inhibition at $8{\mu}g{\cdot}ml^{-1}$ indicating that hydrophobic portion of the compound $\underline{1}$ may facilitate the inhibitory effect. $IC_{50}$ value of compound $\underline{1}$ was $12.6{\pm}0.2{\mu}M$. The primary and secondary Lineweaver Burk and Dixon plots for compound $\underline{1}$ indicated that it is a non-competitive inhibitor with inhibition constant (Ki) value of $23.7{\mu}M$.

• Journal of Microbiology and Biotechnology
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• v.22 no.4
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• pp.494-500
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• 2012

Silk fibroin (SF) peptide has been traditionally used as a treatment for flatulence, spasms, and phlegm. In this study, we examined whether SF peptide enhanced the anti-inflammatory effect of PEP-1-FK506 binding protein (PEP-1-FK506BP) through comparing the anti-inflammatory activities of SF peptide and/or PEP-1-FK506BP. In the presence or absence of SF peptide, transduction levels of PEP-1-FK506BP into HaCaT cells and mice skin and anti-inflammatory activities of PEP-1-FK506BP were identified by Western blot and histological analyses. SF peptide alone effectively reduced both mice ear edema and the elevated levels of cyclooxygenase-2, interleukin-6 and $-1{\beta}$, and tumor necrosis factor-${\alpha}$, showing similar anti-inflammatory effect to that of PEP-1-FK506BP. Furthermore, co-treatment with SF peptide and PEP-1-FK506BP exhibited more enhanced anti-inflammatory effects than the samples treated with SF peptides or PEP-1-FK506BP alone, suggesting the possibility that SF peptide and PEP-1-FK506BP might interact with each other. Moreover, the transduction data demonstrated that SF peptide did not affect the transduction of PEP-1-FK506BP into HaCaT cells and mice skin, indicating that the improvement of anti-inflammatory effect of PEP-1-FK506BP was not caused by enhanced transduction of PEP-1-FK506BP. Thus, these results suggest the possibility that co-treatment with SF peptide and PEP-1-FK506BP may be exploited as a useful therapy for various inflammation-related diseases.

• Molecules and Cells
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• v.44 no.11
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• pp.830-842
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• 2021

When perceiving microbe-associated molecular patterns (MAMPs) or plant-derived damage-associated molecular patterns (DAMPs), plants alter their root growth and development by displaying a reduction in the root length and the formation of root hairs and lateral roots. The exogenous application of a MAMP peptide, flg22, was shown to affect root growth by suppressing meristem activity. In addition to MAMPs, the DAMP peptide PEP1 suppresses root growth while also promoting root hair formation. However, the question of whether and how these elicitor peptides affect the development of the vascular system in the root has not been explored. The cellular receptors of PEP1, PEPR1 and PEPR2 are highly expressed in the root vascular system, while the receptors of flg22 (FLS2) and elf18 (EFR) are not. Consistent with the expression patterns of PEP1 receptors, we found that exogenously applied PEP1 has a strong impact on the division of stele cells, leading to a reduction of these cells. We also observed the alteration in the number and organization of cells that differentiate into xylem vessels. These PEP1-mediated developmental changes appear to be linked to the blockage of symplastic connections triggered by PEP1. PEP1 dramatically disrupts the symplastic movement of free green fluorescence protein (GFP) from phloem sieve elements to neighboring cells in the root meristem, leading to the deposition of a high level of callose between cells. Taken together, our first survey of PEP1-mediated vascular tissue development provides new insights into the PEP1 function as a regulator of cellular reprogramming in the Arabidopsis root vascular system.

• Electronics and Telecommunications Trends
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• v.30 no.3
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• pp.64-73
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• 2015

최근 위성통신은 물리계층의 고속 모뎀, 링크 계층에서의 고효율 패킷처리 기술 등의 발달로 양방향 광대역 멀티미디어 통신 서비스를 제공할 수 있는 기반을 마련하였다. 그러나 긴 전송 지연시간과 유선망에 비해 여전히 높은 패킷 손실률을 갖는 위성링크 고유의 특징은 현재 통신을 위해 가장 많이 사용하는 전송계층 프로토콜인 TCP(Transmission Control Protocol)를 여전히 위성망에서 제대로 동작시키기 어렵게 만들고 있다. 이에 본고에서는 위성망에서 TCP가 갖는 문제점을 해결하기 위해 도입된 PEP(Performance Enhancing Proxy) 기술에 대해서 관련 표준문서에서부터, 다양한 PEP 구성형태, 그리고 응용계층, 전송계층, 네트워크 계층에 따라 각각 적용된 PEP 주요 기술들을 살펴보고, 더불어 해외의 주요 PEP 제품들의 특징들을 분석함으로써 PEP 관련 전반적인 기술동향을 살펴보고자 한다.

• Information and Communications Magazine
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• v.32 no.10
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• pp.11-17
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• 2015

네트워크 중심전에서 위성통신체계에 대한 중요성은 증가하고 있고, 차기 위성 통신 체계의 요구사항들을 만족하기 위해서는 PEP (Performance Enhancing Proxy) 기술의 적용이 필수적이다. 본 고에서는 차기 군 위성 통신 체계에서 적용 가능한 PEP 주요기술들과 상용 제품들의 특성을 알아보고, cross-layer 기반 PEP기술과 SOTM (Satellite communication On-The-Move) 단말을 위한 PEP 기술 동향에 대해서 살펴본다.