• Bulletin of the Korean Chemical Society
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• 제34권2호
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• pp.545-548
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• 2013

It has been shown that calculating atomic charges using quantum mechanical level theory greatly improves the accuracy of docking. A protocol was developed and shown to be effective. That this protocol works is just a manifestation of the fact that electrostatic interactions are important in protein-ligand binding. In order to investigate how the same protocol helps in prediction of binding affinities, we took a series of known cocrystal structures of influenza neuraminidase inhibitors with the receptor and performed docking with Glide SP, Glide XP, and QPLD, the last being a workflow that incorporates QM/MM calculations to replace the fixed atomic charges of force fields with quantum mechanically recalculated ones at a given docking pose, and predicted the binding affinities of each cocrystal. The correlation with experimental binding affinities considerably improved with QPLD compared to Glide SP/XP yielding $r^2$ = 0.83. The results suggest that for binding sites, such as that of neuraminidase, which are laden with hydrophilic residues, protocols such as QPLD which utilizes QM-based atomic charges can better predict the binding affinities.

• 통합자연과학논문집
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• 제4권4호
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• pp.273-277
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• 2011

It's a threat for the public health that H1N1 (Influenza virus A) causes disease and transmits among humans. WHO (world health organization) declared that the infections caused by the new strain had reached pandemic proportions. The approved neuraminidase inhibitors (Zanamivir and Oseltamivir) and related investigative drug (BCX-1812) are potent, specific inhibitors of influenza A and B viruses. These drugs are highly effective to prevent influenza A and B infections. Early therapeutic use reduces illness duration and respiratory complications. Recently, we found one of the potent inhibitor of erystagallin A ($IC_{50}$ of 2.04 ${\mu}M$) for neuraminidase target, this inhibitor shows most similar structure to its natural substrate, sialic acid. Therefore, we chose 1l7f to get the receptor structure for docking study among many crystal structures. A docking study has been performed in Surflex-Dock module in SYBYL 8.1. In the present study, we attempt to compare the docking studies of pterocarpin and erystagallin A with neuraminidase receptor structure. In the previous report, the methoxy group of pterocarpin had H-bonding with Arg residues. The present docking results for erystagallin A showed the backbone of hydroxyl group shows significant H-bonding interactions with Arg152 and Arg292. The results showed that erystagallin A interacts more favorably with distinctive binding site rather than original active site. Therefore, we tried to reveal plausible binding mode and important amino acid for this inhibitor using docking and site id search calculations of Sybyl. The results obtained from this work may be utilized to design novel inhibitors for neuraminidase.

• Mycobiology
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• 제47권2호
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• pp.256-260
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• 2019

Neuraminidase (NA) cleaves the glycosidic bond linkages of sialic acids to release the mature virions from infected cells and has been an attractive therapeutic target for anti-influenza agents. In our ongoing investigation of NA inhibitors in mushroom extracts, we found that the extract the fruiting body of Glaziella splendens potently inhibited neuraminidase. The fruiting bodies of G. splendens were extracted and partitioned successively with hexane, ethyl acetate, and butanol. The ethyl acetate soluble-layer was subjected to silica gel and Sephadex LH-20 column chromatographies, and MPLC to obtain five compounds (1-5). Their structures were determined by spectroscopic methods. NA inhibitory activity of these compounds was evaluated using NAs from recombinant rvH1N1, H3N2, and H5N1 influenza A viruses. One compound (1) was elucidated as a new azaphilone derivative, and four compounds (2-5) were identified as entonaemin A, comazaphilone D, rubiginosin A, and entonaemin B, respectively. Compounds 3 and 4 showed considerable inhibitory activity against three types of neuraminidases with the $IC_{50}$ values of 30.9, 41.8, and $35.7{\mu}M$ for 3 and 46.5, 50.4, and $29.9{\mu}M$ for 4, respectively. This study reveals that the fruiting bodies of G. splendens possess azaphilone derivatives with the NA inhibitory activity. This is the first report on the isolation of neuraminidase inhibitors from the fruiting bodies of G. splendens.

• Bulletin of the Korean Chemical Society
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• 제25권10호
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• pp.1575-1577
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• 2004

• 한국동물학회지
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• 제29권3호
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• pp.171-180
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• 1986

단백질 분해효소, neuraminidase 및 EDTA가 아메바의 배양기표면 흡착, 세포표면의 미세구조 및 생화학적 조성에 미치는 영향을 concanavalin A(con A) cytochemistry 및 SDS PAGE에 의해 조사하였다. Con A cytochemistry에 의해 세포표면 바깥쪽의 filamentous(F)층과 안쪽의 amorphous(A)층이 쉽게 구분되었다. Neuraminidase로 처리한 아메바는 대조군에 비해 용기표면 흡착성과 펴짐이 증가하였으며 A층과 F층에 더 많은 con A결합부위가 노출되었다. Trypsin 및 proteinase K로 처리한 아메바는 각각 12시간, 48시간동안 용기표면에 부착하지 못하였으며, proteinase K의 처리는 A층의 con A결합부위 및 모든 glycoprotein을 제거시키는 효과를 낳았으며, trypsin은 세포막의 PAS염색물질에는 아무런 변화를 초래하지 않았으나 A층과 F층의 con A결합부위를 제거하였다. 이들 효소 및 EDTA처리에 의해 세포 표면의 mucopolysaccharide 일부가 분리되었다. 아메바를 monovalent con A로 처리하였을 때도 아메바는 용기표면에 부착하지 못하고 cytolysis되었다. 이상의 결과로 아메바의 용기표면 흡착에는 세포막의 glycoprotein과 A층의 mucopolysaccharide간의 상호작용에 의해서 이루어지는 것으로 보인다.

• Mycobiology
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• 제44권2호
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• pp.117-120
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• 2016

During our ongoing investigation of neuraminidase inhibitors from medicinal fungi, we found that the fruiting bodies of Phellinus igniarius exhibited significant inhibitory activity against neuraminidase from recombinant H3N2 influenza viruses. Two active compounds were isolated from the methanolic extract of P. igniarius through solvent partitioning and Sephadex LH-20 column chromatography. The active compounds were identified as phelligridins E and G on proton nuclear magnetic resonance ($^1H$ NMR) and electrospray ionization mass measurements. These compounds inhibited neuraminidases from recombinant rvH1N1, H3N2, and H5N1 influenza viruses, with $IC_{50}$ values in the range of $0.7{\sim}8.1{\mu}M$.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2016년도 춘계학술대회 및 임시총회
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• pp.41-41
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• 2016

Influenza viruses are RNA viruses that belong to the Orthomyxoviridae family, and those can be divided into three types; A, B, and C, which based on the differences of the inner nucleoproteins and genomic structures. All three genera differ in their genomic structure and nucleoprotein content, they are further classified into various serotypes based on the two surface glycoproteins, hemagglutinin (HA) and neuraminidase (NA). These glycoproteins play crucial roles in viral infection and replication. Hemagglutinin mediates binding of virions to sialic acid receptors on the surfaces of target cells at the initial stage of infection. Neuraminidase cleaves the glycosidic bonds of sialic acids from the viral and cell surfaces to release the mature virions from infected cells, after viral replication. Because NA plays an important role in the viral life cycle, it is considered an attractive therapeutic target for the treatment of influenza. The methanolic extracts of Phellinus baumii and Phellinus igniarius exhibited significant activity in the neuraminidase inhibition assay. Polyphenolic compounds were isolated from the methanolic extracts. The structures of these compounds were determined to be hispidin, hypholomine B, inoscavin A, davallialactone, phelligridin D, phelligridin E, and phelligridin G by spectroscopic methods. Compounds inhibited the H1N1 neuraminidase activity in a dose-dependent manner with $IC_{50}$ values of 50.9, 22.9, 20.0, 14.2, 8.8, 8.1 and $8.0{\mu}M$, respectively. Moreover, these compounds showed anti-influenza activity in the viral cytopathic effect (CPE) reduction assay using MDCK cells. These results suggests that the polyphenols from P. baumii and P. igniarius are promising candidates for prevention and therapeutic strategies against viral infection.

• 대한유전성대사질환학회지
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• 제6권1호
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• pp.32-39
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• 2006

저자들은 출생 후 정상적인 발달을 보이다가 생후 6개월부터 의식과 운동 발달의 퇴행을 보이던 13개월 환아에서 효소 검사를 시행하여 ${\beta}$-galactosidase의 결핍을 확인하고 $GM_1$-gangliosidosis type 1으로 진단하였지만, 후에 추가적으로 시행한 효소 검사에서 ${\alpha}$-neuraminidase의 결핍도 발견되어 galactosialidosis로 진단한 증례를 경험하였기에 문헌 고찰과 함께 보고하고자 한다.

• Journal of Applied Biological Chemistry
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• 제66권
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• pp.1-6
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• 2023

Dendranthema zawadskii is a one of the popular plants as native in South Korea. In this study, linarin was isolated and purified using silica-gel, Diaion, and Sephadex LH-20 from the aerial parts of D. zawadskii. The chemical structure was completely identified through spectroscopic data including 1D, 2D nucleic magnetic resonance, and HRFABMS. Furthermore, linarin inhibited the bacterial neuraminidase (BNA) activity with 13.5 μM of IC₅₀ dose-dependently. Through the enzyme kinetic experiments, linarin as BNA inhibitor exhibited a typical noncompetitive inhibition mode which K_m was contestant and V_max decreased as the concentration of the inhibitor increased. It was further identified that the inhibition constant was 16.0 μM. Linarin was the most abundance metabolite in the aerial part of D. zawadskii extract by UHPLC-TOF/MS analysis. Therefore, D. zawadskii and its main component are expected that it can be effectively used for the infection and inflammation caused by bacteria.

• 한국미생물·생명공학회지
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• 제48권3호
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• pp.303-309
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• 2020

대표적인 한방 보약 처방인 원방공진단을 재해석한 침향공진단 (당귀, 녹용, 산수유, 및 침향의 혼합추출물)을 유산균으로 발효하고, 침향공진단 성분 중 발효를 통해 증가하는 성분을 분리, 정제하고 nodakenetin임을 동정하였다. 발효 전 침향공진단(침향공진단 농축액 1% 함유 MRS 배지, unfermented Gongjin-dan, GD) 및 발효후 침향공진단(침향공진단 발효액, fermented Gongjin-dan, FGD)에서의 nodakenetin 함량 분석 결과, 각각 6 ㎍/ml과 70 ㎍/ml으로 발효를 통해 nodakenetin이 약 10배 이상 증가하였다. 한편, 고서에 전해지는 공진단의 면역력 강화 효능에 근거하여, GD 및 FGD의 인플루엔자 바이러스 증식 억제 효능을 확인하고자 Neuraminidase (NA) 활성 평가법(NA activity assay)을 실시하였다. 실험 결과, GD는 NA 활성을 억제하지 못하였으나, FGD는 농도의존적으로 NA 활성을 억제하였으며 500 ㎍/ml에서 대조군 대비 약 92%의 억제율을 보였다. 또한, 발효를 통해 증가한 침향공진단의 성분인 nodakenetin과 그 배당체인 nodakenin에 대한 NA 활성 평가 결과, nodakenin은 NA 활성을 거의 억제하지 못하였으나, nodakenetin은 농도의존적으로 NA 활성을 억제하였으며 250 ㎍/ml에서 대조군 대비 약 68%의 억제율을 보였다. 이상의 결과들을 종합하여, 유산균 발효를 통해 침향공진단 내에 미량 존재하던 nodakenetin이 nodakenin의 가수분해로 인해 증가하였으며, NA 활성 억제 성분인 nodakenetin이 증가함으로 인해 FGD도 높은 NA 활성 억제 효능을 보였다고 판단할 수 있었다.