• 미생물학회지
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• 제45권2호
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• pp.215-221
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• 2009

대장균에서 비천연 아미노산을 단백질 생합성시 특정 위치에 삽입하는 방법의 하나로 amber suppressor tRNA와 여기에 비천연 아미노산을 특이적으로 결합할 수 있는 변형된 aminoacyl-tRNA synthetase 쌍을 이용한다. 이러한 기술의 개발을 위해 필요한 여러 요소 중 하나는 이러한 시스템이 대장균에서 얼마나 잘 작동하는지를 확인할 수 있는 in vivo 보고시스템을 설정하는 것이다. 본 논문에서는 $\beta$-galactosidase 유전자의 N-말단에 amber 코돈을 삽입한 보고유전자를 제작하였으며, 이를 대장균(DH10B)의 chromosomal DNA에 삽입하여 DH10B(Tn:lacZam) 균주를 개발하였다. Genomic PCR과 Southern blot 분석을 통하여 lacZ amber 유전자가 대장균의 염색체에 삽입된 것을 확인하였으며, DH10B(Tn:lacZam)은 amber suppression을 유도할 수 있는 벡터가 형질 전환될 경우만 $\beta$-galactosidase 활성을 나타냈다. DH10B(Tn:lacZam)에 효모균의 amber suppressor $tRNA^{Tyr}$와 Tyrosyl-tRNA synthetase 쌍을 동시에 발현하는 벡터를 형질전환하였을 때, amber suppression에 의해서 $\beta$-galactosidase 활성이 나타났다. 하지만 이 활성은 대장균의 amber suppressor $tRNA^{Gln}$를 발현하는 pSupE2를 형질전환하였을 때와 비교 하여 매우 낮은 $\beta$-galactosidase 활성을 나타냈다. 이러한 결과는 DH10B(Tn:lacZam) 균주가 $\beta$-galactosidase 활성을 통하여 정성 및 정량적으로 in vivo amber suppression 활성을 비교 분석할 수 있는 특성을 가졌음을 나타낸다.

• 한국축산식품학회지
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• 제36권4호
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• pp.487-493
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• 2016

The antimicrobial activity of bovine lactoferrin hydrolysates (bLFH) was measured against Pseudomonas strains (P. syringae and P. fluorescens) in vitro. To compare susceptibility to bLFH, minimal inhibitory concentration (MIC) values were determined using chemiluminescence assays and paper disc plate assays. Antimicrobial effect against P. fluorescens was not observed by either assay, suggesting that bLFH did not exhibit antimicrobial activity against P. fluorescens. However, a significant inhibition of P. syringae growth was observed in the presence of bLFH. The addition of bLFH in liquid or solid medium inhibited growth of P. syringae in a dose-dependent manner. Furthermore, a bLFH peptide with antimicrobial activity toward P. syringae was isolated and identified. The N-terminal amino acid sequences of thus obtained antimicrobial bLFH peptides were analyzed by a protein sequencer and were found to be Leu-Arg-Ile-Pro-Ser-Lys-Val-Asp-Ser-Ala and Phe-Lys-Cys-Arg-Arg-Trp-Gln-Trp-Arg-Met. The latter peptide sequence is known to be characteristic of lactoferricin. Therefore, in the present study, we identified a new antimicrobial peptide against P. syringae, present within the N-terminus and possessing the amino acid sequence of Leu-Arg-Ile-Pro-Ser-Lys-Val-Asp-Ser-Ala.

• Journal of Genetic Medicine
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• 제18권2호
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• pp.147-151
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• 2021

The Say-Barber-Biesecker-Young-Simpson variant of Ohdo syndrome (SBBYSS) (Online Mendelian Inheritance in Man #603736) is a rare autosomal dominant disorder and clinically features blepharophimosis with ptosis, a mask-like facial appearance, cryptorchidism, congenital heart defect, long thumbs/great toes, and thyroid dysfunction. The etiology of SBBYSS has been shown to be due to heterozygous KAT6B gene mutation. Here we report a case of a neonate with SBBYSS identified a novel mutation in KAT6B gene. The patient showed typical dysmorphic facies, cryptorchidism with micropenis, overriding fingers, and long thumbs and toes at birth. He had also hypothyroidism, large atrial septal defect, and sensorineural hearing loss. The next generation sequencing identified a heterozygous novel variant, c.5206C>T (p.Gln1736Ter) in KAT6B gene. At the 9 months of age, he underwent patch closure for atrial septal defect. Until the 12-month follow-up, he was under-developed.

• 생명과학회지
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• 제20권10호
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• pp.1544-1548
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• 2010

본 연구에서는 QRDRs의 유전자 돌연변이와 목시플로사신의 농도와의 관계를 알아보기 위하여 목시플로사신의 농도를 단계적으로 높여가며 Mycoplasma hominis (M. hominis)에 작용시켜 목시플로사신에 내성을 갖는 균주 6주(M1, M4, M8, M16, M32, M64)를 만들었고, 이 돌연변이주들의 MIC는 각각 0.5, 4, 8, 16, 32, 64 ${\mu}g$/ml이었다. 이 균들의 염기서열을 분석하였더니 모든 돌연변이주들에서 Arg163Thr (GyrA), Pro445Gln (ParE) 아미노산 치환이 관찰 되었고, 목시플로사신의 농도가 높아질수록 Ser153Lys (GyrA, ${\geq}4{\mu}g$/ml), Ser91Ile (ParC, ${\geq}16{\mu}g/ml$), Val450Phe (GyrB, ${\geq}64{\mu}g/ml$) 등과 같은 아미노산의 치환이 추가로 관찰되었다. 이러한 아미노산의 치환이 목시플로사신의 내성과 연관이 있는 것으로 생각되며, 특히 GyrB 단백질의 아미노산 치환은 목시플로사신의 고도 내성과 연관이 있는 것으로 생각된다.

• Journal of Microbiology and Biotechnology
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• 제27권9호
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• pp.1711-1715
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• 2017

In this study, we characterized the $bla_{NDM-5}$-bearing plasmid in a Klebsiella pneumoniae isolate that had lost the plasmid during serial passage. We determined the complete sequences of the plasmid pCC1410-2, which was extracted from a K. pneumoniae ST709 isolate collected at a Korean hospital from which two NDM-5-producing K. pneumoniae isolates were subsequently isolated. As a result, the pCC1410-2 plasmid had a backbone structure that was similar to those of two plasmids previously reported from the same hospital, but lacked some antibiotic resistance genes ($bla_{TEM-1}$, rmtB, mphR(A), mrx(A), and mph(A)). A 9-bp repeating unit encoding three amino acids (Gln-Gln-Pro) was inserted in TraD in pCC1410-2. Thus, the pCC1410-2 plasmid might be transferred from the previously identified carbapenem-resistant K. pneumoniae, but some delections and inversions might have occurred during the process. We compared the transfer frequency and stability of the plasmids. The relative frequency of conjugative transfer and stability in the host were significantly lower in pCC1410-2 than in previously reported $bla_{NDM-5}$-bearing plasmids in Korea. A low transfer frequency and instability in the host may cause underestimation of carbapenemase-producing Enterobacteriaceae in the clinical setting and in surveillance studies.

• 통합자연과학논문집
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• 제10권2호
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• pp.105-109
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• 2017

Urotensin-2 receptor (UTS2R) is the most potent vasoconstrictor and plays a major role in the pathophysiology of various cardiovascular diseases and becomes a potential target for human pharmacotherapy. Hence, we have performed molecular docking of six antagonists with different inhibitory activity against UTS2R into its binding site. The binding mode of these antagonists was obtained using Surflex dock program interfaced in Sybyl-X2.0. The residues such as GLN278, THR304, TYR305, THR300, LEU299, CYS302, ASP47, TYR100 and THR304 are found in interaction between UTS2R and its antagonists. This study could be useful for identifying and analyzing the important residues involved in binding site of UTS2R receptor.

• 대한의생명과학회지
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• 제12권3호
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• pp.225-231
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• 2006

Fibrinolytic enzyme was purified from the fruiting bodies of Lepista nuda, using DEAE-Cellulose chromatography, Phenyl Sepharose chromatography, and Mono-S column chromatography. The substance has a molecular weight of 30006.62 Da as measured by MALD-TOF mass spectrometry. The N-terminal amino acid sequence of the enzyme was Tyr-Pro-Ser-Pro-Ser-His-Gln-Thr-Ala-Val-Asn-Ala-Ile-Ile-X. The activity of the enzyme was inhibited by PMSF, indicating that the enzyme is a serine protease. No inhibition was found with E-64, pepstatin, and EDTA. It has broad substrate specificity for synthetic peptides. The enzyme was stable up to $30^{\circ}C$. The enzyme hydrolyzes both Aa and y chains of human fibrinogen but did not show any reactivity for $B{\beta}$ chain of human fibrinogen.

• 한국미생물·생명공학회지
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• 제40권1호
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• pp.57-65
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• 2012

B. polyfermenticus CJ6가 생산하는 항진균 물질을 분리 정제하기 위하여 SPE, preparative HPLC, reverse phase-HPLC를 통한 정제를 시행하였다. Preparative HPLC로부터8, B, C의 3개의 항진균 활성 분획을 분리하였으며, LC/MS분석 결과 B. polyfermenticus CJ6는 2종의 iturin A($C_{14}$, $C_{15}$), 3종의 surfactin($C_{13}$, $C_{14}$, $C_{15}$), 4종의 fengycin A($C_{14}$, $C_{15}$, $C_{16}$, $C_{17}$)와 2종의 fengycin B($C_{16}$, $C_{17}$)를 생산하는 것으로 추정되었다. 분리된 항진균 활성 분획의 안정성 실험을 결과 iturin을 함유한 8번 분획은 pH, 열, 효소처리에 안정하였으나 50-$70^{\circ}C$에서 24시간 처리 시에는 항진균 활성이 다소 감소되었다. Surfactins과 fengycins을 포함하는 것으로 추정되는 B 분획은 온도에는 매우 안정하나 pH 3.0과 protease(type I) 및 ${\alpha}$-chymotrypsin 처리에 의하여 항진균활성이 감소되었다. Fengycins 만을 함유한 C 분획은 열과 pH 처리에서 모두 안정하였으나 protease(type I) 처리에 의하여 활성이 감소되었다. 항진균 활성 8번 분획은 reversephase-HPLC를 통하여 2개의 단일 피크가 분리되었으며, 아미노산 조성 분석 결과 Asx, Tyr, Gln, Pro, Ser의 분자비가 3:1:1:1:1으로서 iturin A의 아미노산 서열과 일치하는 것으로 확인되었다. 본 연구를 통하여 B. polyfermenticus CJ6는다양한 항진균 활성 lipopeptides를 생산하는 것을 알 수 있으며, 항진균 활성이 우수한 B. polyfermenticus CJ6 균주의 생물방제 및 생물보존제로서의 활용이 기대된다.

• 한국자기공명학회논문지
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• 제24권4호
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• pp.136-142
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• 2020

Apolipoprotein B-100 (apo B-100), the main protein component that makes up LDL (Low density lipoprotein), consists of 4,536 amino acids and serves to combine with the LDL receptor. The oxidized LDL peptides by malondialdehyde (MDA) or acetylation in vivo were act as immunoglobulin (Ig) antigens and peptide groups were classified into 7 peptide groups with subsequent 20 amino acids (P1-P302). The biomimetic peptide P99 (KGTYG LSCQR DPNTG RLNGE) out of B-group peptides carrying the highest value of IgM antigens were selected for structural studies that may provide antigen specificity. Circular Dichroism (CD) spectra were measured for peptide secondary structure in the range of 190-260 nm. Experimental results show that P99 has pseudo α-helice and random coil structure. Homonuclear (COSY, TOCSY, NOESY) 2D-NMR experiments were carried out for NMR signal assignments and structure determination for P99. On the basis of these completely assigned NMR spectra and proton distance information, distance geometry (DG) and molecular dynamic (MD) were carried out to determine the structures of P99. The proposed structure was selected by comparisons between experimental NOE spectra and back-calculated 2D NOE results from determined structure showing acceptable agreement. The total Root-Mean-Square-Deviation (RMSD) value of P99 obtained upon superposition of all atoms were in the set range. The solution state P99 has mixed structure of pseudo α-helix and β-turn(Gln[9] to Thr[13]). These NMR results are well consistent with secondary structure from experimental results of circular dichroism. Structural studies based on NMR may contribute to the prevent oxidation studies of atherosclerosis and observed conformational characteristics of apo B-100 in LDL using monoclonal antibodies.

• Tuberculosis and Respiratory Diseases
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• 제59권3호
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• pp.257-265
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• 2005

연구 배경 : 리팜핀 내성 균주에서 리파부틴 약제의 교차 내성정도와 리팜핀 내성-리파부틴 감수성 결핵균의 rpoB 유전자 돌연변이의 특성을 알아보고자 연구를 실시하였다. 연구 방법 : 감수성검사에서 리팜핀에 내성인 균주를 선정하여 리파부틴 농도 $0-80{\mu}g/ml$ 농도로 재접종하여 감수성 여부를 확인하였다. 리팜핀-내성균주 모두 염기서열 분석을 통하여 리파부틴 감수성과의 관계를 조사하였다. 역교잡 방법으로 리파부틴 감수성균을 구별하였다. 연구 결과 : 우리나라에서 분리된 리팜핀 내성인 201균주 중에서 41균주(20.4%)는 리파부틴에 감수성을 보였다. 리파부틴 감수성을 보이는 rpoB 유전자 돌연변이는 Leu511Pro, Ser512Arg, Gln513Glu, Asp516Ala, Asp516Gly, Asp516Val, Asp516Tyr, Ser522Leu, His526Asn, His526Leu, His526Cys, Arg529Pro, Leu533Pro 등 이었다. 역교잡 방법을 이용하였을 경우 rpoB 돌연변이를 가진 균주 중에서 리파부틴 감수성균의 민감도는 92.5%이었고, 특이도는 96.1%이었다. 결 론 : 리팜핀 내성균이라도 약 20.4% (95% 신뢰구간: 14.8% to 26.0%)가 리파부틴 약제에 감수성이므로, 우리나라의 다제내성 결핵환자의 치료에서도 리파부틴이 중요한 약제로서 역할을 할 수 있음이 밝혀졌다. 향후 다제내성 결핵 환자에서의 리파부틴의 치료 효과에 대한 임상적 연구가 필요하다.