• Molecules and Cells
• /
• v.19 no.2
• /
• pp.157-166
• /
• 2005

Transfer RNA (tRNA) is a key molecule to decode the genetic information on mRNA to amino aicds (protein), in a ribosome. For tRNA to fulfill its adopter function, tRNA should be processed into the standard length, and be post-transcriptionally modified. This modification step is essential for the tRNA to maintain the canonical L-shaped structure, which is required for the decoding function of tRNA. Otherwise, it has recently been proposed that modification procedure itself contributes to the RNA (re)folding, where the modification enzymes function as a kind of RNA chaperones. Recent genome analyses and post-genome (proteomics and transcriptomics) analyses have identified genes involved in the tRNA processings and modifications. Furthermore, post-genomic structural analysis has elucidated the structural basis for the tRNA maturation mechanism. In this paper, the recent progress of the structural biology of the tRNA processing and modification is reviewed.

• Journal of Microbiology and Biotechnology
• /
• v.10 no.6
• /
• pp.753-758
• /
• 2000

Human leptin is identified as a 16kDa (146 amino acids) protein secreted from adipocytes which influences body weight homeostasis. In order to produce active leptin, the human obese gene coding for leptin was expressed in Bacillus subtilis WB600 strain which is deficient in six extracellular proteases. The recombinant leptin was produced in a culture supernatant, and in a culture supernatant, it was contained as high as 48% for total proteins. After simple purification steps, which consisted of ammonium sulfate precipitation and anion-exchange column chromatography, 2.3 mg of leptin with a purity greater than 95% was obtained from the 0.51 culture with the recovery yield of 38.3%. The purified leptin showed the correct folding structure with one disulfied bond.

• Biomedical Science Letters
• /
• v.13 no.2
• /
• pp.157-160
• /
• 2007

Endoplasmic reticulum (ER) plays formation of disulfide bonds and proper folding of secretory proteins. Cellular responses to ER stress enhances the stress-activated kinase pathway and the induces a lot of immediate-early genes. Among of them, the early growth response-1 (Egr-1), a transcription factor, which plays an important role in cell growth, development, differentiation, apoptosis and various types of injury. For that reason, we have tested the expression of Egr-1 against ER stress inducible drugs (tunicamycin, DTT, A23187 and BFA) to understand what kind of aspect occurred by ER stresses.

• The Journal of Natural Sciences
• /
• v.18 no.1
• /
• pp.1-8
• /
• 2007

An efficient sampling method of computer simulation is reviewed. Using the method, several thermodynamic states can be investigated at a time in a single simulation. It is due to the ability of the method to explore the relevant parts of configuration space equally for every state being investigated. The method can be used in simulations of complex systems such as biopolymers which are still greatly hampered by the multi-minima problem. In this article I present a brief theoretical review of the method and illustrate how to realize it in the simulations.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.12
• /
• pp.4195-4198
• /
• 2011

Intramolecular ${\pi}-{\pi}$ and ${\sigma}-{\pi}$ interactions are omnipresent for numerous energetic and structural phenomena in nature, and the exact description of these nonbonding interactions plays an important role in the accurate prediction of the three-dimensional structures for numerous interesting molecular systems such as protein folding and polymer shaping. We have selected two prototype molecular systems for benchmarking calculations of intramolecular ${\pi}-{\pi}$ and ${\sigma}-{\pi}$ interactions. Accurately describing conformational energy of such systems requires highly elaborate but very expensive ab initio methods such as coupled cluster singles, doubles, and (triples) (CCSD(T)). Our calculations reveal a double hybrid density functional incorporating dispersion correction (B2PLYP-D) that agrees excellently with the CCSD(T) results, indicating that B2PLYP-D can serve as a practical method of choice.

• Biomedical Science Letters
• /
• v.11 no.3
• /
• pp.349-353
• /
• 2005

The globin in cytosol receives the heme in mitochondria and folds to the hemoglobin within erythrocyte. Two mechanisms have been proposed that the heme was transfered post-translationally or cotranslationally to the globin. In this research, how the globin in cytosol receives post-translationally the heme from membranes was studied according to pH and phospholipid composition. Globins dissolved in various pH buffer solutions $(PH\;3\~7)$ were rapidly added into the bulk of egg phosphatidylcholine $100\%\;or\;60\%$ liposomes containing hemin in pH 7 buffer solution. Hemin was very highly transferred to globin at pH 4 and 6. Also, hemin was more efficiently transfered to globin in egg phosphatidylcholine $100\%$ than in $60\%$ liposomes.

• BMB Reports
• /
• v.37 no.4
• /
• pp.394-401
• /
• 2004

The purpose of this paper is to suggest that the prominence of Haldane's explanation for enzyme catalysis significantly hinders investigations in understanding enzyme structure and function. This occurs despite the existence of much evidence that the Haldane model cannot embrace. Some of the evidence, in fact, disproves the model. A brief history of the explanation of enzyme catalysis is presented. The currently accepted view of enzyme catalysis -- the Haldane model -- is examined in terms of its strengths and weaknesses. An alternate model for general enzyme catalysis (the Shifting Specificity model) is reintroduced and an assessment of why it may be superior to the Haldane model is presented. Finally, it is proposed that a re-examination of many current aspects in enzyme structure and function (specifically, protein folding, x-ray and NMR structure analyses, enzyme stability curves, enzyme mimics, catalytic antibodies, and the loose packing of enzyme folded forms) in terms of the new model may offer crucial insights.

• Proceedings of the Korean Biophysical Society Conference
• /
• 2001.06a
• /
• pp.35-35
• /
• 2001

The conformational study on cyclic Ac-Cys-Pro-Xaa-Cys-NHMe (Ac-CPXC-NHMe; X = Ala, Val, Leu, Aib, Gly, His, Phe, Tyr, Asn, and Ser) peptides has been carried out using the ECEPP/3 force field and the hydration shell model in the unhydrated and hydrated states. This work has been undertaken to investigate structural implications of the CPXC sequence as the chain reversal for the initiation of protein folding and as the motif for active site of disulfide oxidoreductases.(omitted)

• Journal of the Korean Society of Food Culture
• /
• v.28 no.6
• /
• pp.657-663
• /
• 2013

This study analyzed fish paste containing Lagocephalus lunaris powder (LLP). The moisture, crude ash, crude protein, and crude lipid content of LLP were 6.21%, 1.03%, 74.50%, and 1.21% respectively. The tested concentrations of LLP were 0, 3, 5, and 7%. The pH of the samples ranged from 6.75 to 6.89, and moisture content ranged from 75.23% to 76.95%. The L values of the samples decreased as the concentrations of LLP decreased, and the a and b values increased. In addition, the folding test results in all test samples were "AA", indicating a good mean flexibility. In the texture meter test, the hardness, strength, springiness, gumminess, and chewiness increased according to increasing concentrations of LLP. In the sensory evaluation, the fish paste prepared with 5% LLP were preferred over other fish pastes. These results suggest that LLP can be applied to fish paste for substantially increasing its quality and functionality.

• Proceedings of the Korean Information Science Society Conference
• /
• 2001.10a
• /
• pp.595-597
• /
• 2001

오늘날 인간 유전체 프로젝트(Human Genome Project)의 완성은 인간의 모든 유전자 서열정보를 제공하게 되었으며, 이러한 데이터를 바탕으로 생명현상과 관련된 산업 및 연구가 각광받게 되었다. 특히 생명체의 특정 기능을 파악하기 위한 단백질 3차 구조에 대한 연구가 활발히 진행중이다. 본 논문에서는 단백질 3차 구조를 추상적으로 기술 할 수 있는 표현기법을 기술한다. 제안된 표현기법은 단백질 2차 구조요소($\alpha$-나선구조와 $\beta$-병풍구조)를 이용하여 인접한 구성요소간의 접힘(folding)에 대한 관계를 기술하여 추상적인 단백질 3차 구조를 표현한다. 제안된 표현기법으로 기술된 추상적 단백질 3차 구조 표현은 단백질 구조에 대한 보다 빠른 이해와 다른 단백질 구조와 비교될 수 있는 장점을 지닌다.