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Protein unfolding by ATP-dependent proteases

  • Lee, Cheolju;Michael Schwartz;Sumit Prakash;Masahiro Iwakura;Andreas Matouschek
    • Proceedings of the Korean Biophysical Society Conference
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    • 2003.06a
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    • pp.34-34
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    • 2003
  • Protein unfolding is a key step in several cellular processes, including protein translocation across some membranes and protein degradation by ATP-dependent proteases. C1pAP protease and the proteasome can actively unfold proteins in a process that hydrolyzes ATP, These proteases catalyze unfolding by processively unraveling their substrates from the attachment point of the degradation signal. As a consequence, the ability of a protein to be degraded depends on its structure as well as its stability. An ${\alpha}$-helix is easier to unravel than a ${\beta}$-strand. In multidomain proteins, independently stable domains are unfolded sequentially. The steric constraints imposed on substrate proteins during their degradation by the proteasome were investigated by constructing a model protein in which specific parts of the polypeptide chain were covalently connected through disulfide bridges. The cross-linked model proteins were fully degraded by the proteasome, but two or more cross-links retarded the degradation slightly. Our results suggest that the pore of the proteasome allows the concurrent passage of at least three stretches of a polypeptide chain, and also explain the limited degradation by the proteasome that occurs in the processing of the transcription factor NF-KB, and also implicate difficulty in degradation of amyloidal aggregates by the proteasome

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Formation of DNA-Protein Crosslink at Oxidized Abasic Site Mediated by Human DNA Polymerase Iota and Mitochondrial DNA Polymerase Gamma

  • Son, Mi-Young;Jun, Hyun-Ik;Goo, Sun-Young;Sung, Jung-Suk
    • Biomedical Science Letters
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    • v.15 no.1
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    • pp.1-8
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    • 2009
  • Human genomic DNA is continuously attacked by oxygen radicals originated from cellular metabolic processes and numerous environmental carcinogens. 2-deoxyribonolactone (dL) is a major type of oxidized abasic (AP) lesion implicated in DNA strand scission, mutagenesis, and formation of covalent DNA-protein crosslink (DPC) with DNA polymerase (Pol) ${\beta}$. We show here that human DNA polymerase (Pol)${\iota}$ and mitochondrial $Pol{\gamma}$ give rise to stable DNA-protein crosslink (DPC) formation that is specifically mediated by dL lesion. $Pol{\gamma}$ mediates DPC formation at the incised dL residue by its 5'-deoxyribose-5-phosphate (dRP) lyase activity, while $Pol{\gamma}$ cross links with dL thorough its intrinsic dRP lyase and AP lyase activities. Reactivity in forming dL-mediated DPC was significantly higher with $Pol{\gamma}$ than with $Pol{\iota}$. DPC formation by $Pol{\gamma}$, however, can be reduced by an accessory factor of $Pol{\gamma}$ holoenzyme that may attenuate deleterious effects of crosslink adducts on mitochondrial DNA. Comparative kinetic analysis of DPC formation showed that the rate of DPC formation with either $Pol{\iota}$ or $Pol{\gamma}$ was lower than that with $Pol{\beta}$. These results revealed that the activity of catalytic lyase in DNA polymerases determine the efficiency of DPC formation with dL damages. Irreversible crosslink formation of such DNA polymerases by dL lesions may result in a prolonged strand scission and a suicide of DNA repair proteins, both of which could pose a threat to the genetic and structural integrity of DNA.

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In Vitro Cytotoxicity of Novel Platinum(II) Coordination Complexes Containing Diaminocyclohexane and Diphenylphosphines

  • Jung, Jee-Chang;Kim, Young-Kyu;Park, Seung-Joon;Chung, Joo-Ho;Chang, Sung-Goo;Lee, Kyung-Tae;Baek, Min-Son;Park, Jong-Jip;Rho, Young-Soo
    • The Korean Journal of Physiology and Pharmacology
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    • v.2 no.3
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    • pp.395-401
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    • 1998
  • We have synthesized new platinum(II) analogs containing 1,2-diaminocyclohexane (dach) as a carrier ligand, 1,3-bis(diphenylphosphino) propane (DPPP) /1,2-bis(diphenylphosphino)ethane (DPPE) as a leaving group and nitrates to improve solubility. In the present study, the cytotoxicity of $[Pt(trans-l-dach)(DPPP)]\;2NO_3$ (KHPC-001) and $[Pt(trans-l-dach)(DPPE)]\;2NO_3$ (KHPC-002) was evaluated and compared on various P-388 cancer cell lines and porcine kidney cell line ($LLC-PK_1$). The new platinum complexes demonstrated high efficacy on P-388 mouse leukemia cell line as well as cisplatin-resistant (P-388/CDDP) and adriamycin-resistant (P-388/ADR) P-388 cell lines. The intracellular platinum content was measured by a flame atomic absorption spectrophotometer (FAAS), and it was comparable to the results of $IC_{50}$ of the three complexes on $LLC-PK_1$ and P-388/S cells, while only DPPE compound was accumulated in high volume in P-388/ADR and P-388/CDDP cells. While the DNA-interstrand cross-links of KHPC-001, KHPC-002 and cisplatin were similar on P-388/S leukemia cells, these new platinum complexes were much less DNA cross-linking to a kidney derived cell line, $LLC-PK_1$. These results indicate that KHPC-001 and KHPC-002 are a third-generation platinum complexes with potent antitumor activity and low nephrotoxicity.

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Anti-glycation effect and renal protective activity of Colpomenia sinuosa extracts against advanced glycation end-products (AGEs) (불레기말(Colpomenia sinuosa)의 최종당화산물 저해 효능 및 신장 보호 효과)

  • Kim, Mingyeong;Cho, Chi Heung;Kim, Sera;Choi, In-Wook;Lee, Sang-Hoon
    • Journal of Marine Bioscience and Biotechnology
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    • v.13 no.2
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    • pp.94-103
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    • 2021
  • Here, we evaluated the anti-glycation effects and renal protective properties of 70% (v/v) ethanolic extract of Colpomenia sinuosa (CSE) against AGEs -induced oxidative stress and apoptosis at different concentrations (1, 5, and 20 ㎍/mL). At 20 ㎍/mL, CSE showed that anti-glycation activities via the inhibition of AGE formation (51.1%), inhibition of AGEs-protein cross-linking (61.7%), and breaking of AGEs-protein cross-links (33.3%), were significantly (###p < 0.001 vs. non-treated group) lower than the nontreated group. Methylglyoxal (MGO) significantly (***p < 0.001) reduced cell viability (24.4%) and increased reactive oxygen species (ROS) level (642.3%), MGO accumulation (119.4 ㎍/mL), and apoptosis (55.0%) in mesangial cells compared to the nontreated group. Pretreatment with CSE significantly (###p < 0.001) increased cell viability (57.8%) and decreased intracellular ROS (96.5%), MGO accumulation (80.0 ㎍/mL), and apoptosis (22.6%) at 20 ㎍/mL. Additionally, we confirmed intracellular AGEs reduction by CSE pretreatment. Consequently, our results suggest that CSE is a good source of natural therapeutics for managing diabetic complications by the antiglycation effect and renal protective activity against MGO-induced oxidative stress.

Evaluating Health-Promoting Schools Based on WHO Standards in Yangpyung-Gun, Korea (WHO 건강증진학교 평가개념을 적용한 사정 및 평가 - 앙평군 초.중.고등학교별 차이 분석 -)

  • Sohn, Ae-Ree;Kim, Bo-Ram;Kim, Seok-Hyeon;Shin, Young-Jeon;Ahn, Dong-Hyun;Choi, Bo-Youl
    • The Journal of Korean Society for School & Community Health Education
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    • v.9 no.1
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    • pp.1-15
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    • 2008
  • Objectives: The concept of the WHO's 'Health Promoting School (HPS)' has been advocated as an approach enhancing national health promotion through school. Health-promoting schools have existed internationally about 20 years. Yet there are few comprehensive evaluation results. Methods: This study is a cross-sectional survey, aiming to explore the HPS status. A total of 31 elementary, middle and high schools were included, and 260 teachers participated in the study. The schools were assessed based on tools of HPS. Results: 'School health promotion and protection services' and 'school's physical environment' had the highest scores, 80.7 score and 77.4 score, respectively. Community links and action competencies for healthy living were two areas with the lowest scores. Conclusions: These results are a good source of reference for assessment and evaluation of Health Promoting Schools programs. For the improvement of efficiency of Health Promoting Schools programs, cooperation with family and community link and support system would be necessary.

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A Study on the Typological Alteration of the Courtyard in Modern Architecture (현대건축에서 나타나는 중정의 유형 변화에 관한 연구)

  • Lee, Jung-Min;Kim, Kook-Sun;Woo, HyunYong
    • Korean Institute of Interior Design Journal
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    • v.21 no.4
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    • pp.40-47
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    • 2012
  • Courtyard is evolving from the conventional one element of a building far beyond into independent peremeter of urban architecture, of which function has been darmatically upgraded from embedded traditional air fluiding, nutural lighting system into where full fledged function can be experienced so much as your imagimation reaches taking major social responsibility such as intact offline social networking which links people from neighbors, inter / extra buiding openness which allow people can communicate among othewise between themselves and artificial natural environmental emelents supplier where people resort to relaxation and natural healing. Roles of courtyard has been by far streatched out into nearby natural healing space where people can shake off their unavoidable stresses from the modern life relaxing themselves looking at the sky otherwise observe natural surroundigns such as plants, flowers and waters. Thanks to hereonto mentioned its merits, Courtyard building is widely used and seen as a center of modern urban design in residence, public bilding and urban planned buildings. Courtyard biulding is nowadays boasting their morphological diversity brought out from lots of topological variation, type variants, cross section and inter relationship with the other neighboring spaces. Hence, hereby I have been studied how above mentioned three major peremeters of courtyard has been upgraded in modern architecture comparing the period from 1960 to 1990 and the period starting from 1991.

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Molecular Screening for P53 Mutations among Tobacco Smokers in a Surveyof Awareness of Links between Tobacco, Alcohol Use and Cancer in Saudi Arabia

  • Alshammari, Fawaz D
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.16
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    • pp.6845-6849
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    • 2015
  • Background: Roles of tobacco and alcohol use in etiology of cancer are well established. Alterationin in P53 have essential roles neoplastic change by preventing genome mutation; the aim of this study was to assess the association between P53 mutation and tobacco and alcohol consumption, as well as to assess the epidemiology of tobacco and alcohol use as risk factors for cancer in the adult population of northern Saudi civilians. Materials and Methods: A cross-sectional survey from October 2014 to January 2015, covering 3,398 adults, was performed. P53 mutation molecular detection was performed for 100 tobacco and alcohol users, usingDNA extracted from buccal cells. Results: Of the 3,398 participants 3,253/3398(95.7%) responded, with a male female ratio of 1.10: 1.00. Out of these, 24.8% had smoked tobacco in their lifetime and 2.7% were consumers of alcoholic beverages. None was identified with any P53 mutation. Conclusions: The prevalence of tobacco smoking among the northern Saudi civilians was relatively high. Females' attitudes in tobacco and alcohol related issues were found to be affected by social stigma. Tobacco and alcohol use has no link to P53 gene mutations.

A study on Effects of the Concept Mapping for Concept Formation of Molecular Motion (개념도 작성 활동을 통한 수업이 분자운동 개념 형성에 미치는 효과)

  • 전근배;노석구
    • Journal of Korean Elementary Science Education
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    • v.20 no.1
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    • pp.31-43
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    • 2001
  • The purposes of this study were grasping the degree of students' understanding for course contents through the concept mapping strategy as meaningful learning in science and measuring the effect for change of conception and changing the misconception. The results of the study were as follows: 1. Before the lesson, only 10.7% of students had scientific conception of molecular motion. Other students had various kinds of misconceptions. 2. The extent of concept formation after lesson through the using concept mapping strategy was tested. As a result, compared with the controlled group, the experimental group showed higher extent of sound concept formation (statistical significance level 0.05). 3. The differences between the experimental group and the control group were analyzed into quantitative and qualitative points of view. The results of the comparison showed that the maps of the students were well configured in the categories of the relationship, the hierarchy and the examples; while students showed lower abilities in the category of the cross-links. 4. The student's attitudes to ward concept mapping was positive. Most of the students answered that teaching strategy of concept mapping benefits them in meaningful learning outcomes.

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Optimization Studies for the Production of Microbial Transglutaminase from a Newly Isolated Strain of Streptomyces sp.

  • Macedo, Juliana Alves;Sette, Lara Duraes;Sato, Helia Harumi
    • Food Science and Biotechnology
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    • v.17 no.5
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    • pp.904-911
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    • 2008
  • Covalent cross-links between a number of proteins and peptides explain why transglutaminase may be widely used by food processing industries. The objective of this work was optimization of the fermentation process to produce transglutaminase from a new microbial source, the Streptomyces sp. P20. The strategy adopted to modify the usual literature media was: (1) fractional factorial design (FFD) to elucidate the key medium ingredients, (2) central composite design (CCD) to optimise the concentration of the key components. Optimization of the medium resulted in not only an 86% increase in microbial transglutaminase activity as compared to the media cited in the literature, but also a reduction in the production cost. Optimal fermentation conditions - namely temperature and agitation rate - were also studied, using CCD methodology. Usual conditions of $30^{\circ}C$ and 100 rpm were within the optimal area. All other parameters for enzyme production were experimentally proven to be optimum fermentation conditions.

Structural Characteristics of Cell Walls of Forage Grasses - Their Nutritional Evaluation for Ruminants - - Review -

  • Iiyama, Kenji;Tuyet Lam, Thi Bach
    • Asian-Australasian Journal of Animal Sciences
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    • v.14 no.6
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    • pp.862-879
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    • 2001
  • The walls of all higher plants are organized as a cellulosic, fibrillar phase embedded in a matrix phase composed of non-cellulosic polysaccharides, some proteins and, in most secondary walls, lignin. At the effective utilization of plant biomass, qualitative and quantitative analyses of plant cell walls are essential. Structural features of individual components are being clarified using newly developed equipments and techniques. However, "empirical" procedures to elucidate plant cell walls, which are not due to scientific definition of components, are still applied in some fields. These procedures may give misunderstanding for the effective utilization of plant biomass. In addition, interesting the investigation of wall organization is moving towards not only qualitatively characterisation, but also quantitation of the associations between wall components. These involve polysaccharide-polysaccharide and polysaccharide-lignin cross-links. Investigation of the associations is being done in order to understand the chemical structure, organization and biosynthesis of the cell wall and physiology of the plants. Procedures for qualitative and quantitative analyses based on the definition of cell wall components are reviewed focussing in nutritional elucidation of forage grasses by ruminant microorganisms.