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권문영,서여진,이연미,이애리,이준화 한국자기공명학회 2015 Journal of the Korean Magnetic Resonance Society Vol.19 No.2
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 15N-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/15N-HSQC spectra and thus further NMR study continues to be progressed.
Kwon, Mun-Young,Seo, Yeo-Jin,Lee, Yeon-Mi,Lee, Ae-Ree,Lee, Joon-Hwa Korean Magnetic Resonance Society 2015 Journal of the Korean Magnetic Resonance Society Vol.19 No.2
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.
Kim, Y.T.,Jung, J.H.,Stewart, L.C.,Kwon, S.W.,Holden, J.F.,Park, C.S. Elsevier Publishing Services 2015 MARINE GENOMICS Vol.24 No.3
Methanocaldococcus bathoardescens JH146<SUP>T</SUP> is a hyperthermophilic and obligate hydrogenotrophic methanogen isolated from low-temperature (26<SUP>o</SUP>C) hydrothermal vent fluid at Axial Seamount in the northeastern Pacific Ocean. It is most closely related to the N<SUB>2</SUB>-fixing methanogen Methanocaldococcus sp. FS406-22; however, they differ in that JH146 cannot fix N<SUB>2</SUB> or reductively assimilate nitrate. In this study, we present the complete genome sequence of strain JH146<SUP>T</SUP> (1,607,556bp) with its 1635 protein coding genes, and 41 RNA genes. Our analysis focuses on its methane production via the acetyl-CoA pathway and its deleted gene clusters related to nitrogen assimilation. This study extends our understanding of methanogenesis at high temperatures and the impact of these organisms on the biogeochemistry of subseafloor hydrothermal environments and the deep sea.
Cultivation of the Hyperthermophilic Archaeon Sulfolobus solfataricus in Low-Salt Media
Park, Chan-Beum,Lee, Sun-Bok The Korean Society for Biotechnology and Bioengine 1999 Biotechnology and Bioprocess Engineering Vol.4 No.1
Two low-salt complex media, bactopeptone and desalted yeast extract, were used for high density cultivation of the hyperthermophilic archaeon Sulfolobus solfataricus (DSM 1617). Bactopeptone, which has low mineral ion content among various complex media, was good for cell growth in batch cultures; the maximal cell density in bactopeptone was comparable to that in yeast extract. However, cell growth was rather poor when bactopeptone was added by the fed-batch procedure. Since several vitamins are deficient in abctopeptone, the effect of vitamins on cell growth was examined. Among the vitamins tested, pyridoxine was found to improve the growth rate of S. solfataricus. To reduce the growth inhibition caused by mineral ions, yeast extract was dialyzed against distilled water and then fed-batch cultures were carried out using a fed medium containing desalted yeast extract. Although the concentrations of mineral ions in yeast extract were significantly lowered by the dialysis whether low molecular weight solutes in yest extract are crucial for cell growth, we investigated the effect of trehalose, a most abundant compatible solute in yeast extract, on the growth pattern. Cell densities were increased and the length of the lag phase was markedly shortened by the presence of trehalose, indicating that trehalose plays an important role in the growth of S. solfataricus.
Jung, Tae‐,Yang,Kim, Yae‐,Sel,Oh, Byoung‐,Ha,Woo, Euijeon Wiley Subscription Services, Inc., A Wiley Company 2013 Proteins Vol.81 No.5
<P><B>Abstract</B></P><P>Phosphoserine phosphatase (PSP) catalyzes the final and irreversible step of L‐serine synthesis by hydrolyzing phosphoserine to produce <SMALL>L</SMALL>‐serine and inorganic phosphate. Developing a therapeutic drug that interferes with serine production is of great interest to regulate the pathogenicity of some bacteria and control <SMALL>D</SMALL>‐serine levels in neurological diseases. We determined the crystal structure of PSP from the hyperthermophilic archaeon <I>Thermococcus onnurineus</I> at 1.8 Å resolution, revealing an NDSB ligand bound to a novel site that is located in a fissure between the catalytic domain and the CAP module. The structure shows a half‐open conformation of the CAP 1 module with a unique protruding loop of residues 150–155 that possesses a helical conformation in other structures of homologous PSPs. Activity assays indicate that the enzyme exhibits marginal PSP activity at low temperature but a sharp increase in the <I>k</I><SUB>cat</SUB>/<I>K</I><SUB>M</SUB> value, approximately 22 fold, when the temperature is increased. Structural and biochemical analyses suggest that the protruding loop in the active site might be an essential component for the regulation of the activity of PSP from hyperthermophilic <I>T. onnurineus</I>. Identification of this novel binding site distantly located from the catalytic site may be exploited for the development of effective therapeutic allosteric inhibitors against PSP activity. © Proteins 2013. © 2012 Wiley Periodicals, Inc.</P>
Lee, J.,Seol, E.,Kaur, G.,Oh, Y.K.,Park, S. Pergamon Press ; Elsevier Science Ltd 2012 International journal of hydrogen energy Vol.37 No.15
A novel marine hyperthermophile, Thermococcus onnurineus NA1, was found to grow on C1 carbon compounds, such as formate and carbon monoxide (CO), and produce hydrogen (H<SUB>2</SUB>). In the present study, the growth and H<SUB>2</SUB> production of NA1 were examined to determine its potential as H<SUB>2</SUB> producer. NA1 showed relatively high specific growth rates, 0.48 h<SUP>-1</SUP> and 0.40 h<SUP>-1</SUP> with CO (20%, v/v) and formate (100 mM), respectively, when cultivated in batch mode in a minimal salt medium fortified with 1.0 g L<SUP>-1</SUP> yeast extract. On the other hand, cell growth in both cases stopped at approximately 6 h and the final cell densities were extremely low at 18.2 and 12.1 mg protein L<SUP>-1</SUP> with CO and formate, respectively. The maximum final cell density could be improved greatly to 36.0 mg protein L<SUP>-1</SUP> by optimizing CO content (50%, v/v) and yeast extract concentration (4.0 g L<SUP>-1</SUP>), but it was still very low. During the cell growth, formate and CO were used as energy source rather than carbon source. In the resting cell experiments, NA1 exhibited remarkably high H<SUB>2</SUB> production activities as 385.0 and 207.5 μmol mg protein<SUP>-1</SUP> h<SUP>-1</SUP> for CO and formate, respectively. When formate (100 mM) or CO (100%, v/v) was added repeatedly at 30-35 h intervals, NA1 showed consistent H<SUB>2</SUB> production for 3 cycles with a yield of approximately 1.0 mol H<SUB>2</SUB> mol<SUP>-1</SUP> for both CO and formate. This study suggests that T. onnurineus NA1 has a high H<SUB>2</SUB> production potential from formate or CO but a method for achieving a high cell density culture is needed.
Complete genome sequence of hyperthermophilic archaeon Thermococcus sp. ES1
Jung, J.H.,Kim, Y.T.,Jeon, E.J.,Seo, D.H.,Hensley, S.A.,Holden, J.F.,Lee, J.H.,Park, C.S. Elsevier Science Publishers 2014 Journal of biotechnology Vol.174 No.-
Thermococcus sp. strain ES1 is an anaerobic, hyperthermophilic archaeon from a hydrothermal vent that catabolizes sugars and peptides and produces H<SUB>2</SUB>S from S<SUP>o</SUP>, H<SUB>2</SUB>, acetate and CO<SUB>2</SUB> as its primary metabolites. We present the complete genome sequence of this strain (1,957,742bp) with a focus on its substrate utilization and metabolite production capabilities. The sequence will contribute to the development of heterotrophic archaea for bioenergy production and biogeochemical modeling in hydrothermal environments.