• BMB Reports
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• 제43권2호
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• pp.146-149
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• 2010

Exendin-4 (Ex-4), a peptide secreted from the salivary glands of the Gila monster lizard, can increase pancreatic $\beta$-cell growth and insulin secretion by activating glucagon-like peptide-1 receptor. In this study, we expressed a fusion protein consisting of exendin-4 and the human immunoglobulin heavy chain (Ex-4/IgG-Fc) in E. coli and explored its potential therapeutic use for the treatment of insulin-resistant type 2 diabetes. Here, we show that the Ex-4/IgG-Fc fusion protein induces expression of insulin receptor substrate-2 in rat insulinoma INS-1 cells. Our findings therefore suggest that Ex-4/IgG-Fc overexpressed in E. coli could be used as a potential, long-acting glucagon-like peptide-1 mimetic.

• 약학회지
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• 제52권6호
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• pp.466-470
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• 2008

Human cytomegalovirus expresses an unusual protein kinase UL97, a member of ${H_V}{U_L}$ family of protein kinase. UL97 can phosphorylate nucleoside analogs such as ganciclovir as well as protein/peptide. It has previously been reported that UL97 is able to phosphorylate a KESYSVYVYKV peptide and that P+5 position (K) is important. We examined the extent of contribution of other positions (P-4 through P+6) of the peptide to be substrate of UL97 using alanine substituted peptides (Ala scanning) and deleted peptides. The result suggested that the E (P-2) is negative effect and P+5 (K) is still important. The peptide YSVYVYK is the shortest substrate enough to show high activity, which could be a starting point to develop peptidomimetic drug. This study would give important information to deeply understand the substrate specificity of UL97 and develop an antiviral drug using the small peptide identified here.

• Journal of Plant Biology
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• 제36권4호
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• pp.391-398
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• 1993

식물에서도 동물에서와 같이 RGD(Arg-Gly-Asp) sequence를 매개로 원형질막과 extracellular matrix(ECM)가 연결되어 있다는 사실이 알려지고 있으므로 RGD sequence가 식물세포의 생장, 분화 등의 여러 가지 생리적인 현상에 관여하리라는 가능성을 생각할 수 있다. 그래서 RGD sequence가 당근(Daucus carota L.) 배양세포에서 에틸렌 생성에 미치는 영향을 조사하였다. RGD sequence를 포함하는 합성 peptide는 당근 배양세포에서 에틸렌의 생성을 촉진시켰다. RGD peptide는 Indole-3-acetic acid(IAA)와 함께 처리한 경우 에틸렌 생성을 더욱 촉진시켰으며, ACC synthase의 활성도 증가시켰다. RGD sequence가 에틸렌 생성을 촉진시킬 때 어떠한 특이성이 있는가를 확인하기 위해 이와 유사한 RGE(Arg-Gly-Glu) peptide, RGK(Arg-Gly-Lys) peptide를 각각 처리하여 보았다. RGE peptide는 RGD peptide와 마찬가지로 에틸렌 생성을 촉진시켰으나 RGK peptide는 에틸렌 생성에 영향을 미치지 않았다. 따라서 RGD peptide의 에틸렌 생성 촉진작용은 RGD dequence를 포함하는 RGD peptide가 ACC synthase의 활성을 증가시켜서 일어나는 현상이라 생각되며, 또한 특정한 아미노산 서열을 요구하는 특이적 반응이라고 생각된다.

• 한국축산식품학회지
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• 제43권1호
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• pp.184-194
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• 2023

Recently, interest in food-derived bioactive peptides as promising ingredients for the prevention and improvement of hypertension is increasing. The purpose of this study was to determine the structure and antihypertensive effect of an antioxidant peptide purified from velvet antler in a previous study and evaluate its potential as a various bioactive peptide. Molecular weight (MW) and amino acid sequences of the purified peptide were determined by quadrupole time-of-flight electrospray ionization mass spectroscopy. The angiotensin I-converting enzyme (ACE) inhibition activity of the purified peptide was assessed by enzyme reaction methods and in silico molecular docking analysis to determine the interaction between the purified peptide and ACE. Also, antihypertensive effect of the purified peptide in spontaneously hypertensive rats (SHRs) was investigated. The purified antioxidant peptide was identified to be a pentapeptide Asp-Asn-Arg-Tyr-Tyr with a MW of 730.31 Da. This pentapeptide showed potent inhibition activity against ACE (IC₅₀ value, 3.72 μM). Molecular docking studies revealed a good and stable binding affinity between purified peptide and ACE and indicated that the purified peptide could interact with HOH2570, ARG522, ARG124, GLU143, HIS387, TRP357, and GLU403 residues of ACE. Furthermore, oral administration of the pentapeptide significantly reduced blood pressure in SHRs. The pentapeptide derived from enzymatic hydrolysate of velvet antler is an excellent ACE inhibitor. It might be effectively applied as an animal-based functional food ingredient.

• Journal of Dairy Science and Biotechnology
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• 제25권2호
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• pp.17-20
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• 2007

Bovine lactoferricin(LFcin B) is a peptide of 25 amino acids that originated from the N terminus of bovine lactoferrin, and is characterized as having potent antimicrobial activity against bacteria, fungi, protozoa and viruses. But, direct expression of Lfcin B is lethal to Escherichia coli. For the efficient production of Lfcin B in microorganism, we developed an expression system in which the gene for cationic Lfcin B was fused to an anionic peptide gene, and successfully expressed the concatemeric fusion gene in E. coli. The purified recombinant Lfcin B was found to have antimicrobial activity, as chemically synthesized Lfcin B peptide does.

• The Korean Journal of Pain
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• 제19권2호
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• pp.168-174
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• 2006

Background: Several biochemical mediators, such as substance P, calcitonin gene-related peptide (CGRP) and prostaglandin $E_2$, have been demonstrated to be involved in herniated or degenerated disc-induced radiculopathy. The authors tested the hypothesis that these mediators would existed in the epidural space of humans. Methods: Thirty nine patients were divided into two groups; 27 patients, who were diagnosed with spinal stenosis (stenosis group), and 12 scheduled for epidural anesthesia, without a history of back pain (control group). Under fluoroscopic guidance, an epidural catheter was introduced through the caudal space and placed into the anterior and posterior spaces, up to and around the epidural adhesive area, in the stenosis group. In the control group, the catheter was placed into the posterior epidural space through the L3⁣-4 or L4⁣-5 intervertebral space. Epidural irrigation was performed with 10 ml of saline, via an epidural catheter. Aspirated lavage fluid was collected, and the concentrations of biochemical mediators (substance P, CGRP and prostaglandin $E_2$) measured using an enzyme immunoassay kit. Results: Substance P, CGRP and prostaglandin $E_2$ were detected in all the epidural lavage fluids from both groups. The concentrations of substance P and prostaglandin $E_2$ in the stenosis group were higher than those of the control (P < 0.05). However, there was no difference in the CGRP levels between the two groups. In the stenosis group, the concentrations of these three mediators in the anterior epidural space were no different to those in the posterior space. Conclusions: These results suggest that biochemical mediators, such as substance P and prostaglandin $E_2$, in the epidural space might be partly involved in pain mechanism associated with spinal stenosis.

• 한국미생물·생명공학회지
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• 제32권3호
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• pp.212-217
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• 2004

Glycosyl hydrolase family 26에 속하는 Bacillus subtilis WL-7 mannanase를 코드하는 유전자를 대장균에서 과잉 발현하였다. 아미노 말단의 signal peptide를 포함하거나 포함하지 않은 mannanase 유전자를 각각 pET24a(＋)에 도입하여 재조합 플라스미드 pETMAN과 pENS7를 제조하였다. 이들 플라스미드를 함유하는 Escherichia coli BL21(DE3)에서 mannanase를 발현시킨 결과 signal peptide가 제거된 mannanase유전자의 발현량이 매우 높았다. 그러나 배양온도 $37^{\circ}C$에서 pENS7를 함유한 재조합 대장균에서 과잉 발현된 mannanase는 대부분이 불활성 형태로 존재하였으며, 배양온도를 $31^{\circ}C$이하로 하였을 때 수용화 형태의 효소량이 증가하면서 효소활성이 높아졌다. IPTG에 의해 발현된 재조합 대장균의 균체파쇄 상등액 중에 존재하는 mannanase 활성은 배양온도 $25^{\circ}C$～28$^{\circ}C$에서 가장 높았으며, 전체 단백질량을 기준으로 볼 때는 배양온도 $31^{\circ}C$에서 비활성이 가장 높은 것으로 확인되었다.

• Fisheries and Aquatic Sciences
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• 제15권1호
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• pp.15-19
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• 2012

A new cyclic peptide (six-membered amino acid), gamakamide-E (L-Leu-L-Met (SO)-L-Me-Phe-L-Leu-D-Lys-L-Phe), was isolated as a strongly bitter tasting compound from cultured oysters, Crassostrea gigas. The molecular formula of $C_{43}H_{61}N_7O_8S$ was deduced from high resolution fast atom bombardment mass spectrometry (HR FAB-MS) ($[M+H]^+$ m/z 836.4356 ${\Delta}$= -2.4 mmu). Its unique structure including a hydantoin structure was firstly elucidated by nuclear magnetic resonance (NMR) analysis. Stereochemistries of constituent amino acids were determined by chiral high performanced liquid chromatography analysis of natural and synthesized peptides.

• Journal of Microbiology and Biotechnology
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• 제8권1호
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• pp.34-41
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• 1998

A method was developed for the controlled expression of an antimicrobial peptide magainin in Escherichia coli. A series of concatemeric magainin genes was constructed with a gene amplification vector, and fused to the 3'end of malE gene encoding the affinity ligand, E. coli maltose-binding protein (MBP). The construct directed the synthesis of the fusion protein with the magainin polypeptide fused to the C-terminus of MBP. The fusion protein was expressed in a tightly regulatable expression system which was under the control of an invertible promoter. The MBP-fused magainin monomer was expressed efficiently. However, the expression level of the MBP-fused magainin in E. coli decreased with the increasing size of multimers possibly because of the transcription and translation inhibition by the multimeric peptides. After purification using an amylose affinity column, the fusion protein was digested by factor Xa at a specific cleavage site between the monomers. The recombinant magainin had an antimicrobial activity identical to that of synthetic magainin. This experiment shows that a biologically active, antimicrobial peptide magainin can be produced by fusing to MBP, along with a promoter inversion vector system.

• Journal of Microbiology and Biotechnology
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• 제25권10호
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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.