• Environmental Analysis Health and Toxicology
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• 제29권
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• pp.7.1-7.8
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• 2014

Objectives The present study was designed to systematically characterize the denaturation and the renaturation of double stranded DNA (dsDNA), which is suitable for DNA hybridization. Methods A series of physical and chemical denaturation methods were implemented on well-defined 86-bp dsDNA fragment. The degree of each denaturation was measured and the most suitable denaturation method was determined. DNA renaturation tendency was also investigated for the suggested denaturation method. Results Heating, beads mill, and sonication bath did not show any denaturation for 30 minutes. However probe sonication fully denatured DNA in 5 minutes. 1 mol/L sodium hydroxide (alkaline treatment) and 60% dimethyl sulfoxide (DMSO) treatment fully denatured DNA in 2-5 minutes. Conclusions Among all the physical methods applied, the direct probe sonication was the most effective way to denature the DNA fragments. Among chemical methods, 60% DMSO was the most adequate denaturation method since it does not cause full renaturation during DNA hybridization.

• Journal of Microbiology and Biotechnology
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• 제13권6호
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• pp.989-992
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• 2003

Recombinant human tissue plasminogen activator deletion mutein (Reteplase) is a clinically promising thrombolytic drug. Reteplase cDNA was subcloned into a bacteria expression system, and the resultant recombinant was biologically characterized. The Reteplase was expressed in Escherichia coli as an inclusion body, and the downstream processes of the Reteplase inclusion body included denaturation, renaturation, and purification. A protein disulfide isomerase (PDI) was used to assist the refolding of Reteplase, and it was found to increase the refolding rate from less than 2％ to more than 20％. The refolded Reteplase was purified through two chromatography steps, including lysine-coupled agarose affinity chromatography and then CM-sepharose cation-exchange chomatography. The purity of r-PA was analyzed by Western bolt analysis, and N-terminal amino acid and amino acid composition analyses confirmed the end-product. Reteplase showed higher thrombolytic potency in an animal thrombus model.

• Journal of Microbiology and Biotechnology
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• 제6권6호
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• pp.474-481
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• 1996

Since the commercially available rabbit anti-cyclin D3, generated from c-terminal 16 amino acid residues which are common to human and murine cyclin D3, is highly cross-reactive with many other cellular proteins of mouse, a new rabbit polyclonal anti-cyclin D3 has been raised by using murine cyclin D3 protein expressed at a high level in Escherichia coli as the immunogen. To express murine cyclin D3 protein in E. coli, the cyclin D3 cDNA fragment encoding c-terminal 236 amino acid residues obtained by polymerase chain reaction (PCR) was inserted into the NcoI/BamHI site of protein expression vector, pET 3d. Molecular mass of the cyclin D3 overexpressed in the presence of IPTG (Isopropyl $\beta$-D-thiogalactopyranoside) was approximately 26 kDa as calculated from the reading frame on the DNA sequence, and the protein was insoluble and mainly localized in the inclusion bodies that could be easily purified from the other cellular soluble proteins. When renaturation was performed following denaturation of the insoluble cyclin D3 protein in the inclusion bodies using guanidine hydrochloride, 4.4 mg of soluble form of cyclin D3 protein was produced from the transformant cultured in 100ml of LB media under the optimum conditions. Four-hundred micrograms of the soluble form of cyclin D3 protein was used for each immunization of a rabbit. When the antiserum obtained 2 weeks after tertiary immunization was applied to Western blot analysis, it was able to detect 33 kDa cyclin D3 protein in both murine lymphoma cell line BW5147.G.1.4 and human Jurkat T cells at 3,000-fold dilution with higher specificity to murine cyclin D3, demonstrating that the new rabbit polyclonal anti-murine cyclin D3 generated against c-terminal 236 amino acid residues more specifically recognizes murine cyclin D3 protein than does the commercially available rabbit polyclonal antibody raised against c-terminal 16 amino acids residues.

• Animal cells and systems
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• 제5권3호
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• pp.195-198
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• 2001

Hepatitis B virus (HBV) polymerase, which possesses the activities of terminal binding, DNA polymerase, reverse transcriptase and RNaseH, has been shown to accomplish viral DNA replication through a pregenomic intermediate. Because the HBV polymerase has not been purified, the expression of HBV polymerase was examined in an E. coli expression system that is under the regulation of arabinose operon. The expressed individual domain containing terminal binding protein, polymerase, or RNaseH turned out to be insoluble. The activities of those domains were not able to be recovered by denaturation and renaturation using urea or guanidine-HCI. The expressed reverse transcriptase containing the polymerase and RNaseH domains became extensively degraded, whereas the proteolysis was reduced in a Ion- mutant. These results indicate that Lon protease proteolyzes the HBV reverse transcriptase expressed in E. coli.

• 미생물학회지
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• 제37권4호
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• pp.245-252
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• 2001

MLS (macrolide-lincosamide-streptogramin B) 항생제 내성인자 단백질인 Erm 단백질들은 아미노산 서열 중 그 동일성과 유사성이 높아 구조적으로도 동등한 단백질의 한 집단을 형성한다. 최근 X-ray crystallography에 의해 구조가 결정된 ErmC\` 및 ErmAM 단백질의 구조에 근거하여 ErmSF 단백질도 catalytic domain과 substrate binding domain으로 구분하였고 N-terminal end에 존재하는 catalytic domain의 대량생산을 다양한 pET 발현 vector를 사용하여 시도하였다. 그리고 catalytic domain을 coding하는 DNA 절편은 세 종류를 사용하였다: DNA 절편 1은 Met 1부터 Glu 186까지를 coding하고 DNA 절편 2는 Arg 60부터 Glu 186까지의 정보를 가진 DNA이고 DNA 절편 3은 Arg 60부터 Arg 240까지를 encoding하는 DNA이다. 사용된 다양한 발현 vector중에서 pET19b는 DNA 절편 3, pET23b는 DNA 절편 1과 2를 성공적으로 대량생산하였다. 그러나 대량생산된 catalytic domain들은 불용성 단백질 집합체인 inclusion body를 형성하였다. ErmSF catalytic domain들의 용해성 단백질의 생산을 위하여 chaperone GroESL과 Thioredoxin의 동시 발현 및 배양온도를 $22^{\circ}C$로 낮추어 시도했으나 대량 발현된 단백질의 용해에는 도움을 얻지 못하였다.