• 한국자기공명학회논문지
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• 제19권2호
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• pp.95-98
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• 2015

Reverse gyrase is a hyperthermophile specific protein which introduces positive supercoils into DNA molecules. Reverse gyrase consists of an N-terminal helicase-like domain and a C-terminal topoisomerase domain. The helicase-like domain shares the three-dimensional structure with two tandem RecA-folds (H1 and H2), in which the subdomain H2 is interrupted by the latch domain (H3). To understand the physical property of the hyperthermophile-specific protein, two subdomains af_H1 and af_H23 have been cloned into E. coli expression vector, pET28a. The $^{15}N$-labeled af_H1 and af_H23 proteins were expressed and purified for heteronuclear NMR study. The af_H1 protein exhibits the well-dispersion of amide signals in its $^1H/^{15}N$-HSQC spectra and thus further NMR study continues to be progressed.

• 한국미생물생명공학회소식지:생물산업
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• 제14권3호
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• pp.46-51
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• 2001

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.587-587
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• 2003

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2006년도 제47회 학술심포지움 및 추계국제학술대회
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• pp.91.2-91.2
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• 2006

• Molecules and Cells
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• 제24권3호
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• pp.437-440
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• 2007

$OGL-20P^T$-358 is a novel 66 amino acid residue protein from the hyperthermophile Thermococcus thioreducens sp. nov., strain $OGL-20P^T$, which was collected from the wall of the hydrothermal black smoker in the Rainbow Vent along the mid-Atlantic ridge. This protein, which has no detectable sequence homology with proteins or domains of known function, has a calculated pI of 4.76 and a molecular mass of 8.2 kDa. We report here the backbone $^1H$, $^{15}N$, and $^{13}C$ resonance assignments of $OGL-20P^T$-358. Assignments are 97.5% (316/324) complete. Chemical shift index was used to determine the secondary structure of the protein, which appears to consist of primarily ${\alpha}$-helical regions. This work is the foundation for future studies to determine the three-dimensional solution structure of the protein.

• Applied Microscopy
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• 제30권4호
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• pp.413-421
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• 2000

초고온 archaeon인 Thermococcus profundus에서 실린드형태의 단백질 복합체를 분리, 생화학적 특성과 구조를 규명하였다. 전자현미경과 영상처리 (image processing)를 이용한 구조 분석으로 8개의 subunit으로 이루어진 링 (ring) 형태가 두 개 겹쳐져 가운데 통로를 가지는 실린드형태로 이루어진 복합체임을 알 수 있었다. 또한 60kDa단백질(P60 complex)로 구성된 homomultimer임을 보여 주고 있다. 이 복합체는 $80^{\circ}C$ 이상에서 도 강한 ATPase의 활성을 보여주는 강한 내열성 단백질임을 알 수 있다. P60 complex는 초고온 archaeon이 높은 온도에서 적응하며 생존하는데 매우 중요한 역할을 할 것으로 추정할 수 있다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVI)
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• pp.429-429
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• 2005

• Journal of Microbiology and Biotechnology
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• 제17권8호
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• pp.1249-1253
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• 2007

A hyperthermostable endoglucanase from Pyrococcus horikoshii with the capability of hydrolyzing crystalline cellulose was analyzed. A protein engineering study was carried out to obtain a reduced-size mutant. Five amino acid residues at both the N- and C-terminus were found to be removable without any loss of activity or thermal stability. Site-directed mutagenesis was also performed on R102, N200, E201, H297, Y299, E342, and W377, residues possibly involved in the active center or in the recognition and binding of a cellulose substrate. The activity of the resulting mutants was considerably decreased, confirming that the mutated residues were all important for activity. A reduced-size enzyme, as active as the wild-type endoglucanase, was successfully obtained, plus the residues critical for its activity and specificity were confirmed. Consequently, an engineered enzyme with a reduced size was obtained, and the amino acids essential for activity were confirmed by site-directed mutagenesis and comparison with a known three-dimensional structure.

• Journal of Microbiology and Biotechnology
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• 제16권7호
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• pp.1144-1148
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• 2006

DNA can oxidatively be deaminated by ROS, which converts DNA base amino groups to keto groups and can trigger abnormal mutations, resulting in mutagenesis in organisms. In this study, a noncanonical purine dNTP pyrophosphatase (AfPPase) from a hyperthermophilic archaeon Archaeoglobus fulgidus, which hydrolyzes aberrant nucleoside triphosphates, was overexpressed in E. coli, purified, and characterized. The purified AfPPase showed remarkably high activity for XTP and dITP, suggesting that the 6-keto group of these nucleotides is critical for the reactivity. Under optimal reaction conditions, the reaction rate for these substrates was about 120 times that with dGTP. Therefore, AfPPase may play a significant role in DNA repair by hydrolysis of noncanonical nucleotides before they are misincorporated into DNA.

• BMB Reports
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• 제33권1호
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• pp.82-88
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• 2000

A homologous gene to alanine racemase was cloned from a hyperthermophilic bacterium, Aquifex pyrophilus. The cloned gene encodes a protein of 341 amino acids, which has a significant homology to alanine racemase of Bacillus stearothermophilus, Lactobacillus brevis, and E. coli. When the gene was expressed in Escherichia coli, it produced a 40 kDa protein. The purified protein contains one mole pyridoxal 5-phosphate per one mole of protein, which is essential for catalytic activity of alanine racemase. The purified protein catalyzed racemization of L-alanine to D-alanine, or vice versa, indicating that the cloned gene encoded alanine racemase. It also showed significant racemization activity against L-serine and ${\alpha}-aminobutylic$ acid. The A. pyrophilus alanine racemase showed strong thermostability, and it maintained catalytic activity in the presence of organic solvents.