• Journal of the Korean Magnetic Resonance Society
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• v.24 no.3
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• pp.91-95
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• 2020

Transthyretin (TTR) is an abundant protein in blood plasma and cerebrospinal fluid (CSF), working as a homo-tetrameric complex to transport thyroxine (T₄) and a holo-retinol binding protein. TTR is well-known for its amyloidogenic property; several types of systemic amyloidosis diseases are caused by aggregation of either wild-type TTR or its variants, for which more than 100 mutations were reported to increase the amyloidogenicity of TTR. The rate-limiting step of TTR aggregation is the dissociation of a monomeric subunit from a tetrameric complex. A wide range of biochemical and biophysical techniques have been employed to elucidate the TTR aggregation processes, among which nuclear magnetic resonance (NMR) spectroscopy contributed much to characterize the structural and functional features of TTR during its aggregation processes. The present review focuses on discussing the recent advances of our understanding to the amyloidosis mechanism of TTR and to the structural features of its monomeric aggregation-prone state in solution. We expect that the present review provides novel insights to appreciate the molecular basis of TTR amyloidosis and to develop novel therapeutic strategies to treat diverse TTR-related diseases.

• Journal of the Korean Magnetic Resonance Society
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• v.11 no.2
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• pp.73-84
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• 2007

MTH1821 (UniProtKB/TrEMBL ID O27849) is a 96-residue hypothetical protein from the open reading frame of Methanobacterium thermoautotrophicum H one of the target organisms of structural genomics pilot project. Proteins which contain conserved sequence compared with MTH1821 have not been discovered yet and the functional and structural information for MTH1821 is not available. Here, we present the sequence-specific backbone resonance using multidimensional heteronuc1ear NMR spectroscopy and propose the secondary structure using GetSBY software. The backbone resonances of N, HN, $C_{\alpha}$, $C_{\beta}$, CO and $H_{\alpha}$ which are necessary for a prediction of secondary structure by GetSBY were assigned about 98% (557/568). The secondary structure of MTH1821 confirmed that it is comprised of four strand regions and two helical regions. This report will provide a valuable resource for the calculation solution structure of MTH1821 and for the other hypothetical protein that is targeted for structural-based functional discovery.

• BMB Reports
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• v.37 no.6
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• pp.735-740
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• 2004

Hepatitis C virus (HCV) is a causal agent of the chronic liver infection. To understand HCV morphogenesis, we studied the assembly of HCV structural proteins in insect cells. We constructed recombinant baculovirus expression vectors consisting of either HCV core alone, core-E1, or core-E1-E2. These structural proteins were expressed in insect cells and were examined to assemble into particles. Neither core-E1 nor core-E1-E2 was capable of assembling into virus-like particles (VLPs). It was surprising that the core protein alone was assembled into core-like particles. These particles were released into the culture medium as early as 2 days after infection. In our system, HCV structural proteins including envelope proteins did not assemble into VLPs. Instead, the core protein itself has the intrinsic capacity to assemble into amorphous core-like particles. Furthermore, released core particles were associated with HCV RNA, indicating that core proteins were assembled into nucleocapsids. These results suggest that HCV may utilize a unique core release mechanism to evade the hosts defense mechanism, thus contributing to the persistence of HCV infection.

• Korean Journal of Veterinary Research
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• v.32 no.4
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• pp.555-567
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• 1992

In this study gene encoding structural proteins of a CPV isolate was cloned and sequenced to elucidate the molecular genetical properties of the canine parvoviruses isolated from the field. Six recombinant plasmids of pEP3, p1471, p2070, pEP069, pEP338 and p14711p were constructed from the map positions 22 to 98 of RF DNA to clone the VP1 and VP2 genes of CPV-V20. Sequentialy the gene comprising 3780 nucleotides were sequenced by dideoxy chain termination method. When nucleotide sequence of gene encoding the structural proteins of CPV-V20 was compared with those of other strains, CPV-N, CPV-d and CPV-780929 published previously, DNA, homologies to CPV-V20 were 99.87% with CPV-N, 99.73% with CPV-d, 96.85% with CPV-780929 and 98.4% with FPLV-Carl, respectively. The DNA sequence data of CPV-V20 showed seven point mutations and also deletion of 135 nucleotides from the nucleotide position 4745 to 4879 located in the 3'-noncoding region of CPV-N.

• Molecules and Cells
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• v.25 no.3
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• pp.352-357
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• 2008

Osteoprotegerin (OPG) is a soluble decoy receptor that inhibits osteoclastogenesis and is closely associated with bone resorption processes. We have designed and determined the solution structures of potent OPG analogue peptides, derived from sequences of the cysteine-rich domain of OPG. The inhibitory effects of the peptides on osteoclastogenesis are dose-dependent ($10^{-6}M-10^{-4}M$), and the activity of the linear peptide at $10^{-4}M$ is ten-fold higher than that of the cyclic OPG peptide. Both linear and cyclic peptides have a ${\beta}$-turn-like conformation and the cyclic peptide has a rigid conformation, suggesting that structural flexibility is an important factor for receptor binding. Based on structural and biochemical information about RANKL and the OPG peptides, we suggest that complex formation between the peptide and RANKL is mediated by both hydrophobic and hydrogen bonding interactions. These results provide structural insights that should aid in the design of peptidyl-mimetic inhibitors for treating metabolic bone diseases caused by abnormal osteoclast recruitment.

• Journal of Microbiology and Biotechnology
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• v.29 no.8
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• pp.1184-1192
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• 2019

The influenza A virus is a highly infectious respiratory pathogen that sickens many people with respiratory disease annually. To prevent outbreaks of this viral infection, an understanding of the characteristics of virus-host interaction and development of an anti-viral agent is urgently needed. The influenza A virus can infect mammalian species including humans, pigs, horses and seals. Furthermore, this virus can switch hosts and form a novel lineage. This so-called zoonotic infection provides an opportunity for virus adaptation to the new host and leads to pandemics. Most influenza A viruses express proteins that antagonize the antiviral defense of the host cell. The non-structural protein 1 (NS1) of the influenza A virus is the most important viral regulatory factor controlling cellular processes to modulate host cell gene expression and double-stranded RNA (dsRNA)-mediated antiviral response. This review focuses on the influenza A virus NS1 protein and outlines current issues including the life cycle of the influenza A virus, structural characterization of the influenza A virus NS1, interaction between NS1 and host immune response factor, and design of inhibitors resistant to the influenza A virus.

• Korean Journal of Veterinary Service
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• v.45 no.2
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• pp.125-131
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• 2022

The purpose of this study was to examine antibody titers to structural protein (SP) of the foot-and-mouth disease (FMD) virus after vaccination in animals of the Seoul zoo. After the initial inoculation of FMD vaccine to the susceptible animals of the zoo, a total of 235 blood samples were collected from 42 species of zoo animals during treatment or necropsy. All samples were tested by using enzyme-linked immunosorbent assay (ELISA). The overall positive rate of SP antibodies against FMD virus was 94.0% (221/235). However, the positive rates varied according to animal species. The results of positive rates in 30 species were 100% but in 12 species were 50-94.7%. We showed that most animals that have received FMD vaccine in Seoul zoo have been reached to the level of herd immunity against FMD virus after the vaccination. To the best of our knowledge, this study would be the first report for monitoring the vaccine-induced SP antibody titers against FMD virus after vaccination in various zoo animal species in Korea.

• IMMUNE NETWORK
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• v.16 no.4
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• pp.249-255
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• 2016

Exogenous nucleic acids induce an innate immune response in mammalian host cells through activation of the retinoic acid-inducible gene I (RIG-I). We evaluated RIG-I protein for RNA binding and ATPase stimulation with RNA ligands to investigate the correlation with the extent of immune response through RIG-I activation in cells. RIG-I protein favored blunt-ended, double-stranded RNA (dsRNA) ligands over sticky-ended dsRNA. Moreover, the presence of the 5'-triphosphate (5'-ppp) moiety in dsRNA further enhanced binding affinity to RIG-I. Two structural motifs in RNA, blunt ends in dsRNA and 5'-ppp, stimulated the ATP hydrolysis activity of RIG-I. These structural motifs also strongly induced IFN expression as an innate immune response in cells. Therefore, we suggest that IFN induction through RIG-I activation is mainly determined by structural motifs in dsRNA that increase its affinity for RIG-I protein and stimulate ATPase activity in RIG-I.

• Journal of the Korean Magnetic Resonance Society
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• v.24 no.2
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• pp.38-42
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• 2020

WW domains are small protein modules consisting of three-stranded antiparallel β-sheet, and involved in the protein-protein interaction for various biological systems. We overexpressed and purified WW2 domain from human AIP4/Itch (a member of Nedd4 family) using a pH/temperature dependent cleavage system. The backbone assignments of WW2 domain were completed, and secondary structure was predicted. Furthermore, backbone flexibility of WW2 domain was determined by ¹H-¹⁵N heteronuclear NOE and amide hydrogen exchange experiments. The structural information would contribute to the structural determination of WW2 domain as well as the interaction study of WW2 domain with various binding partners.

• Mass Spectrometry Letters
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• v.11 no.4
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• pp.65-70
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• 2020

Despite its great success in the field of proteomics, mass spectrometry has limited use for determining structural details of peptides, proteins, and their assemblies. Emerging ion mobility spectrometry-mass spectrometry has enabled us to explore the conformational space of protein ions in the gas phase, and further combinations with the gas-phase ion spectroscopy and the collision-induced unfolding have extended its abilities to elucidating the secondary structure and local details of conformational transitions. This review will provide a brief introduction to the combined approaches of IMS-MS with gas-phase ion infrared spectroscopy or collision-induced unfolding and their most recent results that successfully revealed higher-order structural details.