https://repository.kopri.re.kr/handle/201206/5187 2026-04-05T17:41:55Z 2026-04-05T17:41:55Z Lee, Sung Gu Kim, Hak Jun Lee, Jun Hyuck https://repository.kopri.re.kr/handle/201206/6534 2022-03-24T07:12:23Z 2011-01-01T00:00:00Z

Title: Recent Advances in Structural Studies of Antifreeze Proteins Authors: Lee, Sung Gu; Kim, Hak Jun; Lee, Jun Hyuck Abstract: Antifreeze proteins (AFPs) have ice binding affinity, depress freezing temperature and inhibit ice recystallization which protect cellular membranes in polar organisms. Recent structural studies of antifreeze proteins have significantly expanded our understanding of the structure-function relationship and ice crystal growth inhibition. Although AFPs (Type I-IV AFP from fish, insect AFP and Plant AFP) have completely different fold and no sequence homology, they share a common feature of their surface area for ice binding property. The conserved ice-binding sites are relatively flat and hydrophobic. For example, Type I AFP has an amphipathic, single α-helix and has regularly spaced Thr-Ala residues which make direct interaction with oxygen atoms of ice crystals. Unlike Type I AFP, Type II and III AFP are compact globular proteins that contain a flat ice-binding patch on the surface. Type II and Type III AFP show a remarkable structural similarity with the sugar binding lectin protein and C-terminal domain of sialic acid synthase, respectively. Type IV is assumed to form a four-helix bundle which has sequence similarity with apolipoprotein. The results of our modeling suggest an ice-binding induced structural change of Type IV AFP. Insect AFP has β-helical structure with a regular array of Thr-X-Thr motif. Threonine residues of each Thr-X-Thr motif fit well into the ice crystal lattice expanded our understanding of the structure-function relationship and ice crystal growth inhibition. Although AFPs (Type I-IV AFP from fish, insect AFP and Plant AFP) have completely different fold and no sequence homology, they share a common feature of their surface area for ice binding property. The conserved ice-binding sites are relatively flat and hydrophobic. For example, Type I AFP has an amphipathic, single α-helix and has regularly spaced Thr-Ala residues which make direct interaction with oxygen atoms of ice crystals. Unlike Type

2011-01-01T00:00:00Z Jung, Ha Yun 유기영 Kim, Yangmee Lee, Soo Young Heo, Yong-Seok 신환철 Kim, Hak Jun 백장미 임동원 김태오 https://repository.kopri.re.kr/handle/201206/6393 2022-03-24T07:13:59Z 2010-01-01T00:00:00Z

Title: Cloning, purification, crystallization and preliminary X-ray crystallographic analysis of the N-terminal domain of DEAD-box RNA helicase from Staphylococcus su aureus strain Mu50 Authors: Jung, Ha Yun; 유기영; Kim, Yangmee; Lee, Soo Young; Heo, Yong-Seok; 신환철; Kim, Hak Jun; 백장미; 임동원; 김태오 Abstract: DEAD-box helicases are enzymes with an ATP-dependent RNA-unwinding function that are involved in a variety of cellular processes including RNA splicing, ribosome biogenesis and RNA degradation. In this study, the N-terminal domain of DEAD-box RNA helicase from Staphylococcus aureus strain Mu50 was overexpressed in Escherichia coli, purified and crystallized. Diffraction data were collected to 2.60？？resolution using a synchrotron-radiation source. The crystal belonged to space group P1, with unit-cell parameters a = 70.81, b = 80.23, c = 86.25？？, α = 69.54, β = 66.54, γ = 87.32°. The unit cell contained six molecules, with a corresponding V(M) of 2.91？？(3)？Da(-1) and a solvent content of 56.1%.

2010-01-01T00:00:00Z Kim, Kyung Ha Heo, Yong-Seok Kim, Hyun-Kyung Jung, Ha Yun Hyoung, Ji Hye Kim, Hak Jun Kim, Yangmee Lee, Ki Jeung Han, Mi Ra https://repository.kopri.re.kr/handle/201206/6392 2022-03-24T07:14:01Z 2010-01-01T00:00:00Z

Title: Preliminary X-ray crystallographic analysis of the breakage-reunion domain of the GyrA subunit of DNA gyrase from Colwellia psychrerythraea strain 34H Authors: Kim, Kyung Ha; Heo, Yong-Seok; Kim, Hyun-Kyung; Jung, Ha Yun; Hyoung, Ji Hye; Kim, Hak Jun; Kim, Yangmee; Lee, Ki Jeung; Han, Mi Ra Abstract: DNA gyrase is a type II topoisomerase that is essential for chromosome segregation and cell division owing to its ability to modify the topological forms of bacterial DNA. In this study, the N-terminal breakage？reunion domain of the GyrA subunit of DNA gyrase from Colwellia psychrerythraea 34H was overexpressed in Escherichia coli, purified and crystallized. Diffraction data were collected to 2.60 A ° resolution using a synchrotron-radiation source. The crystal belonged to space group P212121, with unit-cell parameters a = 98.98, b = 101.56, c = 141.83 A. The asymmetric unit contained two molecules, with a corresponding VM of 3.18 A 3 Da and a solvent content of 59.9%.

2010-01-01T00:00:00Z Jung, Woongsic Park, Kyoung Sun Shin, Song Yub Kim, Hak Jun https://repository.kopri.re.kr/handle/201206/6546 2022-03-24T07:13:54Z 2010-01-01T00:00:00Z

Title: Determination of the Minimal Sequence Required for Antifreeze Activity of Type I Antifreeze Protein (AFP37) Authors: Jung, Woongsic; Park, Kyoung Sun; Shin, Song Yub; Kim, Hak Jun Abstract: In order to elucidate the minimal sequence required for antifreeze activity of AFP 37, we synthesized a series of N- and C-terminal truncated peptides of AFP 37 with the central two Thr residues (Thr-13 and Thr-24) (Table 1). These truncated peptides (AFP 34, AFP 32, AFP 30, AFP 28, AFP 26, AFP 24, AFP 22 and AFP 20) were synthesized by a stepwise deletion of one residue or two residues from N- and C-terminus of AFP 37. Table 2 summarizes the thermal hysteresis values obtained with a series of truncated peptides of AFP 37. AFP 37, AFP 34, AFP 32, AFP 30 and AFP 28 show a linear dependence of the antifreeze activity on the concentrations of the peptides. AFP 34, AFP 32, AFP 30 and AFP 28 preserved 99.1%, 62.6%,56.16% and 15.9%thermal hysteresis activity of the wild type AFP (AFP 37) at a peptide concentration of 40 mg/mL, respectively. However, a significant hysteresis was not observed with any of the AFP 26, AFP24, AFP22 and AFP 20 at 40 mg/mL (data not shown). These results suggested that the minimalsequence required for antifreeze activity is from residue 5 toresidue 32 of AFP 37 (AFP 28).

2010-01-01T00:00:00Z