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Ziwei Chang,박장수,Ming Lu,Sung-Min Park,Hyun-Kyung Park,강호성,박영상 한국분자세포생물학회 2012 Molecules and cells Vol.33 No.5
The present study highlighted the aromatic-participant interactions in in vivo trimerization of HSF1 and got an insight into the process of HSF1 protecting against apoptosis. In mouse embryonic fibroblasts (MEFs), mutations of mouse HSF1 (W37A, Y60A and F104A) resulted in a loss of trimerization activity, impaired binding of the heat shock element (HSE) and lack of heat shock protein 70 (HSP70) expression after a heat shock. Under UV irradiation, wild-type mouse HSF1 protected the MEFs from UV-induced apoptosis, but none of the mutants offered protection. We found that normal expression of HSF1 was essential to the cell arrest in G2 phase, assisting with the cell cycle checkpoint. The cells that lack normal HSF1 failed to arrest in the G2 phase, resulting in the process of cell apoptosis. We conclude that the treatment with UV or heat shock stre-sses appears to induce the approach of HSF1 monomers directly via aromatic-participant interactions, followed by the formation of a HSF1 trimer. HSF1 protects the MEFs from the stresses through the expression of HSPs and a G2 cell cycle arrest.
Lu, Ming,Chang, Ziwei,Park, Jang-Su Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.11
The activation of heat shock factor 1 (HSF1) can be induced by the changes in environmental pH, but the mechanism of HSF1 activation by acidification is not completely understood. This paper reports that a low pH (pH~6.0) can trigger human HSF1 activation. Considering the involvement of the imidazole group of histidine residues under acid pH stress, an in vitro EMSA experiment, Trp-fluorescence spectroscopy, and protein structural analysis showed that the residue, His83, is the essential for pH-dependent human HSF1-activation. To determine the roles of His83 in the HSF1-mediated stress response affecting the cellular acid resistance, mouse embryo fibroblasts with normal wild-type or mutant mouse HSF1 expression were preconditioned by heating or pH stress. The results suggest that His83 is essential for HSF1 activation or the HSF1-mediated transcription of heat shock proteins, in protecting cells from acid pH stress.
Ming Lu,Ziwei Chang,박장수 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.11
The activation of heat shock factor 1 (HSF1) can be induced by the changes in environmental pH, but the mechanism of HSF1 activation by acidification is not completely understood. This paper reports that a low pH (pH~6.0) can trigger human HSF1 activation. Considering the involvement of the imidazole group of histidine residues under acid pH stress, an in vitro EMSA experiment, Trp-fluorescence spectroscopy, and protein structural analysis showed that the residue, His83, is the essential for pH-dependent human HSF1-activation. To determine the roles of His83 in the HSF1-mediated stress response affecting the cellular acid resistance, mouse embryo fibroblasts with normal wild-type or mutant mouse HSF1 expression were preconditioned by heating or pH stress. The results suggest that His83 is essential for HSF1 activation or the HSF1-mediated transcription of heat shock proteins, in protecting cells from acid pH stress.
Chang, Ziwei,Lu, Ming,Ma, Yunqi,Kwag, Dong-Geon,Kim, Seo-Hyun,Park, Ji-Min,Nam, Bo-Hye,Kim, Young-Ok,An, Cheul-Min,Li, Huayue,Jung, Jee H,Park, Jang-Su Springer-Verlag ; Springer 2015 Amino acids Vol.47 No.3
<P>Recombinant expression in Escherichia coli allows the simple, economical, and effective production of bioactive peptides. On the other hand, the production of native peptides, particularly those rich in disulfide bonds, is a major problem. Previous studies have reported that the use of carrier proteins for fusion expression can result in good peptide yields, but few are folded correctly. In this study, two transmembrane small proteins in E. coli, YoaJ and YkgR, which both orientate with their N-termini in cytoplasm and their C-termini in periplasm, were used for fusion expression. The recombinant production of two peptides, asteropsin A (ASPA) and 관-defensin (BD), was induced in the periplasm of E. coli using a selected carrier protein. Both peptides were expressed at high levels, at yields of approximately 5-10 mg/L of culture. Mass spectrometry showed that the resulting peptide had the same molecular weight as their natural forms. After purification, single peaks were observed by reversed phase high-performance liquid chromatography (RP-HPLC), demonstrating the absence of isoforms. Furthermore, cytoplasmically expressed fusion proteins with a carrier at their C-termini did not contain disulfide bonds. This study provides new carrier proteins for fusion expression of disulfide bond-rich peptides in E. coli.</P>
Xu, Ziwei,Qiu, Lu,Ding, Feng Royal Society of Chemistry 2018 Chemical Science Vol.9 No.11
<▼1><P>The routes towards carbon nanotube's chirality control during growth was revealed by kinetic modelling.</P></▼1><▼2><P>Depending on its specific structure, or so-called chirality, a single-walled carbon nanotube (SWCNT) can be either a conductor or a semiconductor. This feature ensures great potential for building ∼1 nm sized electronics if chirality-selected SWCNTs could be achieved. However, due to the limited understanding of the growth mechanism of SWCNTs, reliable methods for chirality-selected SWCNTs are still pending. Here we present a theoretical model on the chirality assignment and control of SWCNTs during the catalytic growth. This study reveals that the chirality of a SWCNT is determined by the kinetic incorporation of pentagons, especially the last (6<SUP>th</SUP>) one, during the nucleation stage. Our analysis showed that the chirality of a SWCNT is randomly assigned on a liquid or liquid-like catalyst surface, and two routes of synthesizing chirality-selected SWCNTs, which are verified by recent experimental achievements, are demonstrated. They are (i) by using high melting point crystalline catalysts, such as Ta, W, Re, Os, or their alloys, and (ii) by frequently changing the chirality of SWCNTs during their growth. This study paves the way for achieving chirality-selective SWCNT growth for high performance SWCNT based electronics.</P></▼2>
A Differential Privacy Approach to Preserve GWAS Data Sharing based on A Game Theoretic Perspective
Jun Yan,Ziwei Han,Yihui Zhou,Laifeng Lu 한국인터넷정보학회 2022 KSII Transactions on Internet and Information Syst Vol.16 No.3
Genome-wide association studies (GWAS) aim to find the significant genetic variants for common complex disease. However, genotype data has privacy information such as disease status and identity, which make data sharing and research difficult. Differential privacy is widely used in the privacy protection of data sharing. The current differential privacy approach in GWAS pays no attention to raw data but to statistical data, and doesn’t achieve equilibrium between utility and privacy, so that data sharing is hindered and it hampers the development of genomics. To share data more securely, we propose a differential privacy preserving approach of data sharing for GWAS, and achieve the equilibrium between privacy and data utility. Firstly, a reasonable disturbance interval for the genotype is calculated based on the expected utility. Secondly, based on the interval, we get the Nash equilibrium point between utility and privacy. Finally, based on the equilibrium point, the original genotype matrix is perturbed with differential privacy, and the corresponding random genotype matrix is obtained. We theoretically and experimentally show that the method satisfies expected privacy protection and utility. This method provides engineering guidance for protecting GWAS data privacy.
Guangshuo Wang,Fei Zhou,Ziwei Lu,Yingying Ma,Xiaoguang Li,Yu Tong,Xufeng Dong 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.70 No.-
In this study, we reported novel nanocomposites containing cobalt ferrite (CoFe2O4) nanoparticles andmolybdenum disulfide (MoS2) nanosheets (CoFe2O4/MoS2). The obtained CoFe2O4/MoS2 as dispersedphase was used to prepare magnetorheological (MR)fluid and the rheological properties wereinvestigated in detail. The results of transmission electron microscopy showed that the CoFe2O4nanoparticles were homogeneoused decorated on the surface of MoS2 nanosheets. The successfulpreparation of CoFe2O4/MoS2 was further confirmed by X-ray diffraction, X-ray photoelectronspectroscopy, Raman spectroscopy and vibrating sample magnetometer. The CoFe2O4/MoS2 based MRfluid exhibited typical MR effect with increasing viscosity, shear stress, yield stress and dynamic shearmoduli depending on external magneticfields. More importantly, the preparedfluid showed excellentsedimentation stability due to unique two-dimensional structure and reducedfluid-particle densitymismatch.