• BMB Reports
• /
• 제39권3호
• /
• pp.319-328
• /
• 2006

SecA protein, a cytoplasmic ATPase, plays a central role in the secretion of signal peptide-containing proteins. Here, we examined effects of signal peptide and ATP on the oligomerization, conformational change, and membrane binding of SecA. The wild-type (WT) signal peptide from the ribose-binding protein inhibited ATP binding to soluble SecA and stimulated release of ATP already bound to the protein. The signal peptide enhanced the oligomerization of soluble SecA, while ATP induced dissociation of SecA oligomer. Analysis of SecA unfolding with urea or heat revealed that the WT signal peptide induces an open conformation of soluble SecA, while ATP increased the compactness of SecA. We further obtained evidences that the signal peptide-induced oligomerization and the formation of open structure enhance the membrane binding of SecA, whereas ATP inhibits the interaction of soluble SecA with membranes. On the other hand, the complex of membrane-bound SecA and signal peptide was shown to resume nucleotide-binding activity. From these results, we propose that the translocation components affect the degree of oligomerization of soluble SecA, thereby modulating the membrane binding of SecA in early translocation pathway. A possible sequential interaction of SecA with signal peptide, ATP, and cytoplasmic membrane is discussed.

• Preventive Nutrition and Food Science
• /
• 제15권4호
• /
• pp.282-286
• /
• 2010

To isolate a calcium-binding peptide from chlorella protein hydrolysates, chlorella protein was extracted and hydrolyzed using Flavourzyme, a commercial protease. The degree of hydrolysis and calcium-binding capacity were determined using trinitrobenzenesulfonic acid and orthophenanthroline methods, respectively. The enzymatic hydrolysis of chlorella protein for 6 hr was sufficient for the preparation of chlorella protein hydrolysates. The hydrolysates of chlorella protein were then ultra-filtered under 5 kDa as molecular weight. The membrane-filtered solution was fractionated using ion exchange, reverse phase, normal phase chromatography, and fast protein liquid chromatography to identify a calcium-binding peptide. The purified calcium-binding peptide had a calcium binding activity of 0.166 mM and was determined to be 700.48 Da as molecular weight, and partially identified as a peptide containing Asn-Ser-Gly-Cys based on liquid chromatography/electrospray ionization tandem mass spectrum.

• 한국미생물·생명공학회지
• /
• 제33권4호
• /
• pp.319-321
• /
• 2005

본 연구진은 phage display peptide library로부터 $TiO_{2}$ nanoparticle에 binding 하는 peptide를 선별하여 보고한바 있다. 이 중의 하나인 PEP9을 선택하여 alanine scanning mutagenesis를 통하여 mutant peptide를 display하는 phage를 제작하여 $TiO_{2}$에의 binding을 조사하였다. 그 결과, 4번 위치의 proline이 alanine으로 치환된 peptide의 경우 binding activity가 $10\%$로 감소하였고, 2번 valine, 3번 serine, 5번 isoleucine의 치환 peptide는 binding이 $40\%$로 감소하였다. 이러한 사실로 미루어볼 때, PEP9과 $TiO_{2}$ nanoparticle의 결합에는 2, 3, 4, 5번의 아미노산이 만들어내는 3차원적 구조가 중요한 역할을 하는 것으로 결론 내릴 수 있었다.

• 한국미생물·생명공학회지
• /
• 제51권3호
• /
• pp.243-249
• /
• 2023

We recently found that the insect-derived antimicrobial peptide CopA3 (LLCIALRKK) directly binds to and inhibits the proteolytic activation of caspases, which play essential roles in apoptotic processes. However, the mechanism of CopA3 binding to caspases remained unknown. Here, using recombinant GST-caspase-3 and -6 proteins, we investigated the mechanism by which CopA3 binds to caspases. We showed that replacement of cysteine in CopA3 with alanine caused a marked loss in its binding activity towards caspase-3 and -6. Exposure to DTT, a reducing agent, also diminished their interaction, suggesting that this cysteine plays an essential role in caspase binding. Experiments using deletion mutants of CopA3 showed that the last N-terminal leucine residue of CopA3 peptide is required for binding of CopA3 to caspases, and that C-terminal lysine and arginine residues also contribute to their interaction. These conclusions are supported by binding experiments employing direct addition of CopA3 deletion mutants to human colonocyte (HT29) extracts containing endogenous caspase-3 and -6 proteins. In summary, binding of CopA3 to caspases is dependent on a cysteine in the intermediate region of the CopA3 peptide and a leucine in the N-terminal region, but that both an arginine and two adjacent lysines in the C-terminal region of CopA3 also contribute. Collectively, these results provide insight into the interaction mechanism and the high selectivity of CopA3 for caspases.

• 한국식품영양과학회지
• /
• 제33권7호
• /
• pp.1206-1211
• /
• 2004

본 연구는 selenium binding yeast peptide의 식이내 첨가가 돼지의 생산성, 조직내 Se, 혈청내 GSH-Px의 활성 및 돈육의 품질에 미치는 영향을 확인하고자 실시하였다. 3원 교잡종(Duroc ${\times}$ Yorkshire ${\times}$ Landrace) 비육돈 80두를 공시하였으며 시험개시 시의 체중은82.88$\pm$1.23kg이었다. 시험설계는 옥수수-대두박 위주의 식이로서 처리한 대조구(CON：기초식이), 대조구 식이 내 selenium binding yeast peptide 물질을 0.05%(SY1. 대조구＋0.05% selenium binding yeast feptide), 0.1%(SY2： 대조구＋0.1% selenium binding yeast 울ptide) 및 0.2% 첨가한 구(SY3： 대조구＋0.2% selenium binding yeast peptide)로 4개 처리를 하여 처리 당 5반복, 반복 당4두씩 임의 배치하였다. 사양기간 동안의 성장률에 누는 selenium binding yeast peptide를 급여한 처리구가 대조구에 비하여 다소 높은 경향을 보였지만, 유의적인 차이는 보이지 않았다(p＞0.05). 명도를 나타내는 L＊-값은 SY2가 대조구와 SY1에 비하여 유의적인 차이를 보였다(p＜0.05). 적색도를 나타내는 a＊-값은 대조구가 다른 처리구와 비교하여 낮은 수치를 나타내었다(p＜0.05). 혈청 내 Se의 함량은 대조구가 516 mg/mL로 selenium binding yeast peptide를 급여한 처리구에 비하여 낮게 나타났지만 유의 적인 차이는 보이지 않았다(p＞0,05). 등심의 Se 함량은 대조구(0.008 $\mu$g/g)에 비해 SY2(0.021 $\mu$g/g) 및 SY3(0.031 $\mu$g/g)에서 유의적인 차이를 나타냈다(p＜0.05). 신장의 Se함량에서는 SY2와 SY3가 대조구 및 SY1과 비교하여 유의적으로 높게 나타났다(p＜0.05). 간에서는SY1이 대조구에 비하여 높게 나타났다(p＜0.05). 위의 결과를 종합하여 볼 때 비육돈 식이내 selenium binding yeast peptide의 첨가는 등심, 신장 및 간에서 많이 축적되는 것으로 보이며, 육색에도 영향을 미치는 것으로 보인다.

• Journal of Applied Biological Chemistry
• /
• 제53권3호
• /
• pp.174-178
• /
• 2010

탈지 미강으로부터 미강단백질을 추출하고 상업용 단백분해 효소로 가수분해하고 한외여과하여 얻어진 미강단백질 가수분해물을 Sephadex G-15로 분리하여 얻어진 peptide fraction에 칼슘, 철분을 binding하여 칼슘, 철분 함유 peptide를 제조하였다. 추출된 탈지 미강 단백질의 분자량은 10~66 kDa에 분포하고 있었다. 추출된 단백질을 Flavourzyme으로 가수분해 시, 최적 가수분해 시간은 6시간이었으며, 5kDa 이하로 한외여과 하여 얻어진 peptide를 Sephadex G-15로 분획한 결과 4개의 major peak를 얻었는데, 각 fraction의 칼슘, 철분을 binding한 결과 Ca/peptide는 FI에서, Fe/peptide는 F2에서 가장 많은 함량을 나타내었다. 본 연구 결과 얻어진 칼슘, 철분 binding peptide는 biomineral 기능성 식품의 소재로써 식품산업에 활용될 수 있다고 판단된다.

• Mass Spectrometry Letters
• /
• 제6권3호
• /
• pp.80-84
• /
• 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.

• Bulletin of the Korean Chemical Society
• /
• 제31권1호
• /
• pp.202-204
• /
• 2010

• 한국미생물학회:학술대회논문집
• /
• 한국미생물학회 2005년도 International Meeting of the Microbiological Society of Korea
• /
• pp.132-134
• /
• 2005

The CC chemokine, monocyte chemoattractant protein-1 (MCP-1), plays a crucial role in the initiation of atherosclerosis and has direct effects that promote angiogenesis. To develop a specific inhibitor for MCP-1-induced angiogenesis, we performed in vitro selection employing phage display random peptide libraries. Most of the selected peptides were found to be homologous to the second extracellular loops of CCR2 and CCR3. We synthesized the peptide encoding the homologous sequences of the receptors and tested its effect on the MCP-1 induced angiogenesis. Surface Plasmon Resonance measurements demonstrated specific binding of the peptide to MCP-1 but not to the other homologous protein, MCP-3. Flow cytometry revealed that the peptide inhibited the MCP-1 binding to THP-1 monocytes. Moreover, CAM and rat aortic ring assays showed that the peptide inhibited MCP-1 induced angiogenesis. Our observations indicate that the MCP-1-binding peptide exerts its anti-angiogenic effect by interfering with the interaction between MCP-1 and its receptor.

• Bulletin of the Korean Chemical Society
• /
• 제23권10호
• /
• pp.1483-1486
• /
• 2002