https://repository.kopri.re.kr/handle/201206/5152 2026-04-16T00:06:50Z 2026-04-16T00:06:50Z Kim, Eun Jae Han, Se Jong Kim, Hak Jun Lee, Sung Gu Lee, Jun Hyuck Do, Hackwon https://repository.kopri.re.kr/handle/201206/7104 2022-03-24T07:11:43Z 2015-01-01T00:00:00Z

Title: Fed-batch production of ice-binding protein of Flavobacterium frigoris PS1 by recombinant Pichia pastoris Authors: Kim, Eun Jae; Han, Se Jong; Kim, Hak Jun; Lee, Sung Gu; Lee, Jun Hyuck; Do, Hackwon Abstract: Ice-binding proteins (IBPs) inhibit ice growth to permit the survival of polar organisms in the cold environments. The recombinant IBP from an Antarctic bacterium, Flavobacterium frigoris PS1, FfIBP (Flavobacterium frigoris ice-binding protein), was produced using Pichia pastoris expression system. The optimum fermentation temperature and pH for fed-batch production of FfIBP were 30℃ and 5, respectively. The maximal cell density and purified FfIBP were 112 g/L and 70 mg/L, respectively. The thermal hysteresis (TH) activity (0.85℃) of FfIBP obtained using a glycerol-methanol fed-batch culture system was 2-fold higher than that of the LeIBP (Leucosporidium ice-binding protein). This work allows for large-scale production of FfIBP, which could be extended to further application studies using recombinant IBPs.

2015-01-01T00:00:00Z Lee, Sung Gu https://repository.kopri.re.kr/handle/201206/13359 2022-04-22T08:27:41Z 2014-02-28T00:00:00Z

Title: Planning research for the practical application of antifreeze protein Authors: Lee, Sung Gu

2014-02-28T00:00:00Z Kim, Eun Jae Han, Se Jong Kim, Hak Jun Lee, Sung Gu Lee, Jun Hyuck Do, Hackwon https://repository.kopri.re.kr/handle/201206/5920 2022-03-24T07:14:37Z 2014-01-01T00:00:00Z

Title: Production of Antifreeze Protein from Antarctic Bacterium Flavobacterium frigoris PS1 by using Fed-batch Culture of Recombinant Pichia pastoris Authors: Kim, Eun Jae; Han, Se Jong; Kim, Hak Jun; Lee, Sung Gu; Lee, Jun Hyuck; Do, Hackwon Abstract: Antifreeze proteins (AFP) inhibit ice growth to permit the survival of polar organisms in the cold environments. The recombinant AFP from an Antarctic bacterium, Flavobacterium frigoris PS1, FfIBP (Flavobacterium frigoris ice-binding protein), was produced using Pichia pastoris expression system. The optimum fermentation temperature (30°C) and pH (5) for FfIBP production was determined using a fed-batch culture system. The maximal cell density and purified FfIBP were 112 g/L and 70 mg/L, respectively. The thermal hysteresis (TH) activity (0.85℃) of FfIBP obtained using a glycerol-methanol fed-batch culture system was 2-fold higher than that of the LeIBP (Leucosporidium ice-binding protein). This work allows for large-scale production of FfIBP, which could be extended to further application studies using recombinant AFPs.

2014-01-01T00:00:00Z Lee, Jun Hyuck Kim, Hak Jun Do, Hackwon Lee, Chang Woo Han, Se Jong Lee, Sung Gu Park, Hyun https://repository.kopri.re.kr/handle/201206/7251 2022-03-24T07:12:00Z 2014-01-01T00:00:00Z

Title: Purification, crystallization, and preliminary X-ray crystallographic studies of FMN-bound and FMN-free forms of aromatic acid decarboxylase (CpsUbiX) from the psychrophilic bacterium Colwellia psychrerythraea 34H Authors: Lee, Jun Hyuck; Kim, Hak Jun; Do, Hackwon; Lee, Chang Woo; Han, Se Jong; Lee, Sung Gu; Park, Hyun Abstract: The ubiX gene (UniProtKB code Q489U8) of Colwellia psychrerythraea strain 34H has been annotated as a putative flavin mononucleotide- (FMN-) dependent aromatic acid decarboxylase. Based on previous studies of homologous proteins, CpsUbiX is thought to catalyze the decarboxylation of 3-octaprenyl-4-hydroxybenzoate to produce 2-polyprenylphenol in the ubiquinone biosynthesis pathway using a noncovalently bound FMN molecule as a cofactor. However, the detailed mechanisms of this important enzyme are not yet clear and need to be further elucidated. In this study, we found that the V47S single mutation resulted in a loss of FMN binding, resulting in the production of the FMN-free CpsUbiX protein. This mutation likely destabilizes FMN-protein interactions without affecting overall structural folding. To fully characterize the conformational changes upon FMN binding and enzymatic mechanism at the molecular level, the wild-type (FMN-bound) and V47S mutant (FMN-free) CpsUbiX proteins were purified and crystallized using the sitting-drop vapor diffusion method. Furthermore, complete diffraction data sets of FMN-bound (space group C2221) and FMN-free (space group P23) forms were obtained to 2.0 and 1.76 A resolution, respectively.

2014-01-01T00:00:00Z