• Molecules and Cells
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• 제19권3호
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• pp.328-333
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• 2005

Small heat shock proteins (sHSPs) are widely distributed, and their function and diversity of structure have been much studied in the field of molecular chaperones. In plants, which frequently have to cope with hostile environments, sHSPs are much more abundant and diverse than in other forms of life. In response to high temperature stress, sHSPs of more than twenty kinds can make up more than 1% of soluble plant proteins. We isolated a genomic clone, NtHSP18.3, from Nicotiana tabacum that encodes the complete open reading frame of a cytosolic class I small heat shock protein. To investigate the function of NtHSP18.3 in vitro, it was overproduced in Escherichia coli and purified. The purified NtHSP18.3 had typical molecular chaperone activity as it protected citrate synthase and luciferase from high temperature-induced aggregation. When E. coli celluar proteins were incubated with NtHSP18.3, a large proportion of the proteins remained soluble at temperatures as high as $70^{\circ}C$. Native gel analysis suggested that NtHSP18.3 is a dodecameric oligomer as the form present and showing molecular chaperone activity at the condition tested. Binding of bis-ANS to the oligomers of NtHSP18.3 indicated that exposure of their hydrophobic surfaces increased as the temperature was raised. Taken together, our data suggested that NtHSP18.3 is a molecular chaperone that functions as a dodecameric complex and possibly in a temperature-induced manner.

• 한국산학기술학회논문지
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• 제16권11호
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• pp.7582-7588
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• 2015

광대역 통신을 위한 대표적인 비동기 전송방식인 TR 방식은 동기식 레이크 수신기에 비하여 하드웨어 복잡도가 낮아서 주목을 받아왔다. 최근에는 TR 방식보다 효과적인 데이터 전송을 할 수 있는 BCM 방식이 효율적인 비동기 방식으로 인정받고 있다. BCM 방식의 수신기로는 CMSA 방식이 널리 사용되고 우수한 성능을 가진 것으로 알려져 있다. 본 논문에서는 프레임간 혹은 심볼간 간섭이 존재하는 환경에서, BCM으로 송신된 신호에 대하여 CMSA 방식보다 성능이 우수한 수신기를 제안한다. 제안하는 방식은 TR 방식에서와 같이 상관기를 이용한다. TR방식에서는 하나의 기준신호에 근거한 상관기를 사용하는 반면, 제안하는 방식은 BCM으로 전송된 신호를 복조하기 위하여 블록 코드를 이용한 블록 코드 상관기를 사용한다. 모의실험을 통하여, 제안하는 방식은 CMSA 방식보다 비트오율 측면에서 더 우수한 성능을 나타낸다. 특히, 채널모델 CM4 에서 BER = $10^{-3}$ 일 때, SNR 측면에서 5 dB 이득을 얻을 수 있었다.

• BMB Reports
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• 제39권3호
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• pp.253-262
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• 2006

Parkinson's disease (PD) is a common neurodegenerative disorder and is characterized by the progressive loss of dopaminergic neurons in the substantia nigra. Although many studies showed that the aggregation of $\alpha$-synuclein might be involved in the pathogenesis of PD, its protective properties against oxidative stress remain to be elucidated. In this study, human wild type and mutant $\alpha$-synuclein genes were fused with a gene fragment encoding the nine amino acid trans activator of transcription (Tat) protein transduction domain of HIV-l in a bacterial expression vector to produce a genetic in-frame WT Tat-$\alpha$-synuclein (wild type) and mutant Tat-a-synucleins (mutants; A30P and A53T), respectively, and we investigated the protective effects of wild type and mutant Tat-$\alpha$-synucleins in vitro and in vivo. WT Tat-$\alpha$-synuclein rapidly transduced into an astrocyte cells and protected the cells against paraquat induced cell death. However, mutant Tat-$\alpha$-synucleins did not protect at all. In the mice models exposed to the herbicide paraquat, the WT Tat-$\alpha$-synuclein completely protected against dopaminergic neuronal cell death, whereas mutants failed in protecting against oxidative stress. We found that these protective effects were characterized by increasing the expression level of heat shock protein 70 (HSP70) in the neuronal cells and this expression level was dependent on the concentration of transduced WT Tat-$\alpha$-synuclein. These results suggest that transduced Tat-$\alpha$-synuclein might protect cell death from oxidative stress by increasing the expression level of HSP70 in vitro and in vivo and this may be of potential therapeutic benefit in the pathogenesis of PD.

• BMB Reports
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• 제42권3호
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• pp.136-141
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• 2009

Familial Amyotrophic lateral sclerosis (FALS) is a progressive neurodegenetative disorder induced by mutations of the SOD1 gene. Heat shock protein 27 (HSP27) is well-defined as a stress-inducible protein, however the its role in ALS protection has not yet been established. To investigate the role HSP27 may have in SOD1 mutant-mediated apoptosis, human SOD1 or HSP27 genes were fused with a PEP-1 peptide in a bacterial expression vector to produce a genetic in-frame fusion protein, which was then transduced into cells. We found the purified PEP-1-HSP27 fusion proteins can be transduced efficiently into neuronal cells and protect against cell death by enhancing mutant SOD1 activity. Moreover, transduced PEP-1-HSP27 efficiently prevents protein aggregation produced by oxidative stress. These results suggest that transduced HSP27 fusion protein may be explored as a potential therapeutic agent for FALS patients.