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Svensson J, Tarakanov Y, Lee DS, Kinaret JM, Park YW, Campbell EEB. A carbon nanotube gated carbon nanotube transistor with 5 ps gate delay. NANOTECHNOLOGY 2008; 19:325201. [PMID: 21828807 DOI: 10.1088/0957-4484/19/32/325201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Semiconducting carbon nanotubes (CNTs) are attractive as channel material for field-effect transistors due to their high carrier mobility. In this paper we show that a local CNT gate can provide a significant improvement in the subthreshold slope of a CNT transistor compared to back gate switching and provide gate delays as low as 5 ps. The CNT gated CNT transistor devices are fabricated using a two-step chemical vapour deposition technique. The measured transfer characteristics are in very good agreement with theoretical modelling results that provide confirmation of the operating principle of the transistors. Gate delays below 2 ps should be readily achievable by reducing the thickness of the gate dielectric.
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Thirthagiri E, Lee SY, Kang P, Lee DS, Toh GT, Selamat S, Yoon SY, Taib NAM, Thong MK, Yip CH, Teo SH. Evaluation of BRCA1 and BRCA2 mutations and risk-prediction models in a typical Asian country (Malaysia) with a relatively low incidence of breast cancer. Breast Cancer Res 2008; 10:R59. [PMID: 18627636 PMCID: PMC2575532 DOI: 10.1186/bcr2118] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2008] [Revised: 06/18/2008] [Accepted: 07/16/2008] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION The cost of genetic testing and the limited knowledge about the BRCA1 and BRCA2 genes in different ethnic groups has limited its availability in medium- and low-resource countries, including Malaysia. In addition, the applicability of many risk-assessment tools, such as the Manchester Scoring System and BOADICEA (Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm) which were developed based on mutation rates observed primarily in Caucasian populations using data from multiplex families, and in populations where the rate of breast cancer is higher, has not been widely tested in Asia or in Asians living elsewhere. Here, we report the results of genetic testing for mutations in the BRCA1 or BRCA2 genes in a series of families with breast cancer in the multi-ethnic population (Malay, Chinese and Indian) of Malaysia. METHOD A total of 187 breast cancer patients with either early-onset breast cancer (at age </= 40 years) or a personal and/or family history of breast or ovarian cancer were comprehensively tested by full sequencing of both BRCA1 and BRCA2. Two algorithms to predict the presence of mutations, the Manchester Scoring System and BOADICEA, were evaluated. RESULTS Twenty-seven deleterious mutations were detected (14 in BRCA1 and 13 in BRCA2), only one of which was found in two unrelated individuals (BRCA2 490 delCT). In addition, 47 variants of uncertain clinical significance were identified (16 in BRCA1 and 31 in BRCA2). Notably, many mutations are novel (13 of the 30 BRCA1 mutations and 24 of the 44 BRCA2). We report that while there were an equal proportion of BRCA1 and BRCA2 mutations in the Chinese population in our study, there were significantly more BRCA2 mutations among the Malays. In addition, we show that the predictive power of the BOADICEA risk-prediction model and the Manchester Scoring System was significantly better for BRCA1 than BRCA2, but that the overall sensitivity, specificity and positive-predictive value was lower in this population than has been previously reported in Caucasian populations. CONCLUSION Our study underscores the need for larger collaborative studies among non-Caucasian populations to validate the role of genetic testing and the use of risk-prediction models in ensuring that the other populations in the world may also benefit from the genomics and genetics era.
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Chae JI, Ju SK, Lee MK, Park JH, Shim JH, Lee KK, Lee DS. [Cloning of rat TARC cDNA and analysis of tissue-specific mRNA expression]. Mol Biol (Mosk) 2008; 42:639-644. [PMID: 18856064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Thymus and activation-regulated chemokine (TARC) is one that selectively controls the migration of type 2-helper T lymphocytes into inflammatory lesions. TARC is a CC chemokine, and plays an essential role in recruiting CC chemokine receptor 4-positive Th2 cells to allergic lesions. We cloned TARC cDNA from rat thymus using RT-PCR. The rat TARC clone contained a full-length open reading frame encoding 93 amino acids that showed 83% and 66% homology with mouse and human homologs, respectively. The expression of TARC mRNA was mainly in the lymphoid organs, for example, the thymus, spleen, and lymph node. The recombinant TARC was expressed in Escherichia coli and purified in an active form. In addition, the purified rat TARC with S-tagged specifically binds to human CCR4 in CD4.CCR4-transfected HOS cells by Cell-binding assay using flow-cytometry. The TARC cDNA clones obtained in this study will be valuable for future studies on allergic diseases in rats.
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Lee BK, Kim YH, Lee DS. An automated and semi-continuous method for the analysis of water-soluble constituents in PM(2.5). THE SCIENCE OF THE TOTAL ENVIRONMENT 2008; 393:145-153. [PMID: 18237764 DOI: 10.1016/j.scitotenv.2007.11.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Revised: 11/28/2007] [Accepted: 11/30/2007] [Indexed: 05/25/2023]
Abstract
An automated and semi-continuous method for measuring water-soluble constituents in PM(2.5) was developed. The system consists of a multi-tube diffusion scrubber (MTDS), a low temperature particle impactor (LTPI), an inertial air/liquid separator, and two ion chromatography systems. The MTDS acts as an interfering gas removal system and also as a humidifier for growing particles. Since the MTDS operates at 40 degrees C, the loss of volatile compounds and hydrological conversion of nitrogen oxides to nitrite were not of significant concern. The condensation of water vapor, dissolution of soluble constituents, and capture of insoluble particles occurred in the LTPI. The condensed liquid containing the dissolved species and the insoluble particles was separated from the airflow using an inertial air/liquid separator. The analysis of cations and anions in the effluent liquid was performed using two ion chromatography systems. The collection efficiency, including the inlet loss, of the system was 96.6+/-7.1% at an air flow rate of 1.0 SLPM. The limits of detection ranged from 12 to 57 ng/m(3) for major ionic constituents without any pre-concentration procedure. This method was tested in the field and the average data capture was over 90%, demonstrating the reliability of the system.
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Lee DS, Larson MG, Lunetta KL, Dupuis J, Rong J, Keaney JF, Lipinska I, Baldwin CT, Vasan RS, Benjamin EJ. Clinical and genetic correlates of soluble P-selectin in the community. J Thromb Haemost 2008; 6:20-31. [PMID: 17944986 DOI: 10.1111/j.1538-7836.2007.02805.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND P-selectin is a cell adhesion molecule that is involved in atherogenesis, and soluble concentrations of this biomarker reflect cardiovascular risk. However, the clinical correlates and genetic characterization of soluble P-selectin have not been clearly elucidated. OBJECTIVE To describe clinical and genetic correlates of circulating P-selectin in the community. METHODS In Framingham Heart Study Offspring (European descent) and Omni (ethnic/racial minority) participants, we examined the association of cardiovascular risk factors with soluble P-selectin concentrations. In Offspring participants, we evaluated heritability, linkage and association of 29 SELP single-nucleotide polymorphisms (SNPs) with adjusted P-selectin concentrations. RESULTS In multivariable analysis of 3,690 participants (54% women, mean age 60 +/- 10 years), higher log-transformed P-selectin concentrations were inversely associated with female sex and hormone replacement therapy, and positively associated with age, ethnic/racial minority status, cigarette smoking, waist circumference, systolic blood pressure, fasting glucose, and total/high-density lipoprotein cholesterol and triglyceride concentrations. Clinical factors explained 10.4% of the interindividual variability in P-selectin concentrations. In 571 extended pedigrees (n = 1,841) with >or= 2 phenotyped members per family, multivariable-adjusted heritability was 45.4 +/- 5.8%. Among the SELP SNPs examined, a non-synonymous SNP (rs6136) encoding a threonine-to-proline substitution at position 715 was highly significantly associated with decreased P-selectin concentrations (P = 5.2 x 10(-39)), explaining 9.7% of variation after adjustment for clinical factors. CONCLUSIONS Multiple clinical factors and an SNP in the SELP gene were significantly associated with circulating P-selectin concentrations. One SNP in SELP explained significant variation in circulating P-selectin concentrations, even after accounting for known clinical correlates.
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Kim YS, Sohn H, Jin UH, Suh SJ, Lee SC, Jeon JH, Lee DS, Kim CH, Ko JH. Molecular cloning and analysis of the Thermus caldophilus ADP-glucose pyrophosphorylase. Enzyme Microb Technol 2007. [DOI: 10.1016/j.enzmictec.2007.03.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Du XY, Fu YQ, Tan SC, Luo JK, Flewitt AJ, Maeng S, Kim SH, Choi YJ, Lee DS, Park NM, Park J, Milne WI. ZnO film for application in surface acoustic wave device. ACTA ACUST UNITED AC 2007. [DOI: 10.1088/1742-6596/76/1/012035] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Du X, Fu Y, Tan SC, Luo J, Flewitt A, Maeng S, Kim SH, Choi Y, Lee DS, Park RM, Milne B. ZnO film based surface acoustic wave micro-pump. ACTA ACUST UNITED AC 2007. [DOI: 10.1088/1742-6596/76/1/012047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Ahn TB, Kim SY, Kim JY, Park SS, Lee DS, Min HJ, Kim YK, Kim SE, Kim JM, Kim HJ, Cho J, Jeon BS. alpha-Synuclein gene duplication is present in sporadic Parkinson disease. Neurology 2007; 70:43-9. [PMID: 17625105 DOI: 10.1212/01.wnl.0000271080.53272.c7] [Citation(s) in RCA: 174] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE alpha-Synuclein gene (SNCA) multiplication was found in familial Parkinson disease (PD). We examined SNCA multiplication in patients with familial and sporadic PD and multiple system atrophy (MSA). METHODS We screened 1,106 patients with parkinsonism (PD = 906, MSA = 200) for SNCA multiplication by multiplex PCR. Fluorescent in situ hybridization was done to confirm the multiplication. [(123)I]N-omega-Fluoropropyl-2 beta-carbomethoxy-3beta-(4-iodophenyl)-tropane ([(123)I]FP-CIT) SPECT was done in the patients with SNCA multiplication and their family members. RESULTS Three patients were identified as having SNCA duplication. One patient had a positive family history, and two patients were sporadic. Each patient had asymptomatic carriers in their families. The familial case had early onset parkinsonism with rapidly progressive course, cognitive impairment, and dysautonomia. Sporadic cases were more typical of PD. [(123)I]FP-CIT SPECT was abnormal in the patients and normal in the asymptomatic carriers. CONCLUSION SNCA multiplication is present in sporadic Parkinson disease (PD) and needs to be screened. Low penetrance, clinical heterogeneity, and normal dopamine transporter imaging in asymptomatic carriers may suggest the presence of other genetic modifiers or environmental triggers that play a role in the pathogenesis of PD due to SNCA duplication.
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Oh BC, Lee HM, Lim DP, Cho JJ, Lee G, Lee DS, Lee JR. Effect of immature dendritic cell injection before heterotropic cardiac allograft. Transplant Proc 2007; 38:3189-92. [PMID: 17175218 DOI: 10.1016/j.transproceed.2006.10.180] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2006] [Indexed: 11/17/2022]
Abstract
Although dendritic cells (DCs) are unrivaled for initiation of immune responses, the immunomodulatory capacity of chemically fixed DC has not been thoroughly evaluated. We monitored the tolerogenic capacity of chemically fixed DCs using allogeneic heart transplantations. Bone marrow progenitors were differentiated into immature DCs which were then chemically fixed and injected intravenously into recipient mice at 14 days before allogeneic heart transplantation. Chemically fixed DCs markedly prolonged graft survival in the major histocompatibility complex (MHC) I/II mismatch cardiac transplantation (B6 --> B10.A; median survival time [MST] 12.5 days vs >70 days). T cells that encountered chemically fixed DCs showed attenuated apoptotic cell death and inactivated phenotypes after allogeneic heterotropic heart transplantation. Furthermore, when DCs from interleukin (IL)-10-/- mice were treated, the in vitro T-cell response was greater than that from IL-12-/- mice. We have suggested that the chemically fixed DCs may mediate peripheral T-cell tolerance, with therapeutic potential for allogeneic transplantation.
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Kim MK, Cho MK, Song HE, Kim D, Park BH, Lee JH, Kang GB, Kim SH, Im YJ, Lee DS, Eom SH. Crystal structure of UDP-N-acetylenolpyruvylglucosamine reductase (MurB) from Thermus caldophilus. Proteins 2007; 66:751-4. [PMID: 17120230 DOI: 10.1002/prot.21174] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Lin J, Chase JG, Shaw GM, Lotz TF, Hann CE, Doran CV, Lee DS. Long term verification of glucose-insulin regulatory system model dynamics. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2006:758-61. [PMID: 17271788 DOI: 10.1109/iembs.2004.1403269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Hyperglycaemia in critically ill patients increases the risk of further complications and mortality. A long-term verification of a model that captures the essential glucose- and insulin-kinetics is presented, using retrospective data gathered in an intensive care unit (ICU). The model uses only two patient specific parameters, for glucose clearance and insulin sensitivity. The optimization of these parameters is accomplished through a novel integration-based fitting approach, and a piecewise linearization of the parameters. This approach reduces the non-linear, non-convex optimization problem to a simple linear equation system. The method was tested on long-term blood glucose recordings from 17 ICU patients, resulting in an average error of 7%, which is in the range of the sensor error. One-hour predictions of blood glucose data proved acceptable with an error range between 711%. These results verify the model's ability to capture long-term observed glucose-insulin dynamics in hyperglycaemic ICU patients.
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Lee JH, Im YJ, Bae J, Kim D, Kim MK, Kang GB, Lee DS, Eom SH. Crystal structure of Thermus caldophilus phosphoglycerate kinase in the open conformation. Biochem Biophys Res Commun 2006; 350:1044-9. [PMID: 17045964 DOI: 10.1016/j.bbrc.2006.09.151] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Accepted: 09/28/2006] [Indexed: 11/22/2022]
Abstract
Phosphoglycerate kinase (PGK) is a key glycolytic enzyme that catalyzes the reversible transfer of a phosphate from 1,3-bisphosphoglycerate to ADP to form 3-phosphoglycerate and ATP in the presence of magnesium. During catalysis, a conformational change occurs that brings the N- and C-domains of PGK closer together. Here we present the 1.8A crystal structure of unliganded PGK from Thermus caldophilus (Tca). Comparison of the structure of TcaPGK (open conformation) with that of Thermotoga maritima (Tma) PGK (closed conformation) revealed that the conformational change reflects a change in the interaction between the domains. We identified Arg148 as a key residue involved in open-to-closed transition. The open conformation of TcaPGK is stabilized by an interdomain salt bridge between Arg148 and Glu375. The binding of 3-PG (or maybe 1,3-BPG) disrupts this salt bridge and, in ternary complex, the formation of new salt bridge between Arg60 and Asp197 stabilizes the closed conformation.
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Sohn H, Kim YS, Jin UH, Suh SJ, Lee SC, Lee DS, Ko JH, Kim CH. Alteration of the substrate specificity of Thermus caldophilus ADP-glucose pyrophosphorylase by random mutagenesis through error-prone polymerase chain reaction. Glycoconj J 2006; 23:619-25. [PMID: 17123167 DOI: 10.1007/s10719-006-9004-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Revised: 05/16/2006] [Accepted: 07/18/2006] [Indexed: 10/23/2022]
Abstract
Expanding the scope of stereoselectivity is of current interest in enzyme catalysis. In this study, using error-prone polymerase chain reaction (PCR), a thermostable adenosine diphosphate (ADP)-glucose pyrophosphorylase (AGPase) from Thermus caldophilus GK-24 has been altered to improve its catalytic activity toward enatiomeric substrates including [glucose-1-phosphate (G-1-P) + uridine triphosphate (UTP)] and [N-acetylglucosamine-1-phosphate (GlcNAc) + UTP] to produce uridine diphosphate (UDP)-glucose and UDP-N-acetylglucosamine, respectively. To elucidate the amino acids responsible for catalytic activity, screening for UDP-glucose pyrophosphorylase (UGPase) and UDP-N-acetylglucosamine pyrophosphorylase (UNGPase) activities was carried out. Among 656 colonies, two colonies showed UGPase activities and three colonies for UNGPase activities. DNA sequence analyses and enzyme assays showed that two mutant clones (H145G) specifically have an UGPase activity, indicating that the changed glycine residue from histidine has the base specificity for UTP. Also, three double mutants (H145G/A325V) showed a UNGPase, and A325 was associated with sugar binding, conferring the specificity for the sugar substrates and V325 of the mutant appears to be indirectly involved in the binding of the N-acetylamine group of N-acetylglucosmine-1-phosphate.
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Leem JH, Lee DS, Kim J. Risk factors affecting blood PCDDs and PCDFs in residents living near an industrial incinerator in Korea. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2006; 51:478-84. [PMID: 16788748 DOI: 10.1007/s00244-004-0191-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2004] [Accepted: 03/07/2005] [Indexed: 05/10/2023]
Abstract
The contamination sources of polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), such as industrial incinerators, can potentially change the blood levels and isomer patterns of PCDD/DFs in residents living near the incinerators. In this study, we estimated whether the blood levels and isomer patterns of PCDD/DFs in residents living near an incinerator were affected by its presence and investigated factors that characterize the risk of high exposure to PCDD/DFs in the area. We estimated the blood levels and homologue patterns of PCDD/DFs in a group of 40 residents living within 5 km of an industrial incinerator and in a group of 20 residents living 20 km away from an incinerator. We cannot assert that the operation of incinerator facilities was only cause of increased PCDD/DFs in these residents; however, the operation of incinerator facilities in agricultural areas increased PCDD/DF exposure to individuals. The group living next to the industrial incinerator especially represented the typical isomer pattern in which the proportions of OCDDs were lower and those of PCDFs higher than those in the other groups. The high-risk population with increased blood levels of PCDD/DFs included those who had lived longer in the contaminated area as well as those who frequently ate contaminated foods.
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Bae J, Kim D, Choi Y, Koh S, Park JE, Su Kim J, Moon SH, Park BH, Park M, Song HE, Hong SI, Lee DS. A hexokinase with broad sugar specificity from a thermophilic bacterium. Biochem Biophys Res Commun 2006; 334:754-63. [PMID: 16053915 DOI: 10.1016/j.bbrc.2005.06.160] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2005] [Accepted: 06/25/2005] [Indexed: 10/25/2022]
Abstract
A recombinant thermophilic Thermus caldophilus GK24 hexokinase, one of the ROK-type (repressor protein, open reading frames, and sugar kinase) proteins, exists uniquely as a 120 kDa molecule with four subunits (31 kDa), in contrast to eukaryotic and bacterial sugar kinases which are monomers or dimers. The optimal temperature and pH for the enzyme reaction are 70-80 degrees C and 7.5, respectively. This enzyme shows broad specificity toward glucose, mannose, glucosamine, allose, 2-deoxyglucose, and fructose. To understand the sugar specificity at a structural level, the enzyme-ATP/Mg2+-sugar binding complex models have been constructed. It has been shown that the sugar specificity is probably dependent on the interaction energy occurred by the positional proximity of sugars bound in the active site of the enzyme, which exhibits a tolerance to modification at C2 or C3 of glucose.
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Lee JH, Bae J, Kim D, Choi Y, Im YJ, Koh S, Kim JS, Kim MK, Kang GB, Hong SI, Lee DS, Eom SH. Stereoselectivity of fructose-1,6-bisphosphate aldolase in Thermus caldophilus. Biochem Biophys Res Commun 2006; 347:616-25. [PMID: 16843441 DOI: 10.1016/j.bbrc.2006.06.139] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2006] [Accepted: 06/21/2006] [Indexed: 10/24/2022]
Abstract
It was recently established that fructose-1,6-bisphosphate (FBP) aldolase (FBA) and tagatose-1,6-bisphosphate (TBP) aldolase (TBA), two class II aldolases, are highly specific for the diastereoselective synthesis of FBP and TBP from glyceraldehyde-3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP), respectively. In this paper, we report on a FBA from the thermophile Thermus caldophilus GK24 (Tca) that produces both FBP and TBP from C(3) substrates. Moreover, the FBP:TBP ratio could be adjusted by manipulating the concentrations of G3P and DHAP. This is the first native FBA known to show dual diastereoselectivity among the FBAs and TBAs characterized thus far. To explain the behavior of this enzyme, the X-ray crystal structure of the Tca FBA in complex with DHAP was determined at 2.2A resolution. It appears that as a result of alteration of five G3P binding residues, the substrate binding cavity of Tca FBA has a greater volume than those in the Escherichia coli FBA-phosphoglycolohydroxamate (PGH) and TBA-PGH complexes. We suggest that this steric difference underlies the difference in the diastereoselectivities of these class II aldolases.
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Song MJ, Bae J, Lee DS, Kim CH, Kim JS, Kim SW, Hong SI. Purification and characterization of prodigiosin produced by integrated bioreactor from Serratia sp. KH-95. J Biosci Bioeng 2006; 101:157-61. [PMID: 16569612 DOI: 10.1263/jbb.101.157] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2005] [Accepted: 11/08/2005] [Indexed: 11/17/2022]
Abstract
To date, prodigiosin and its analogues which have been shown to have anticancer, cytotoxic and immunosuppressive activities have been isolated from Serratia, Pseudomonas and Streptomyces species, and chemically synthesized. In a previous study, the red pigment content in Serratia sp. KH-95 was enhanced using a casein-enriched medium. Recently, an integrated bioreactor with an internal adsorbent has been developed to increase the production yield and allow easy recovery of the pigment. Thus, this study focused on both purifying and identifying a single red pigment from several pigments attached to the adsorbent in an integrated bioreactor. The red pigment was extracted directly from the internal adsorbent using acidified methanol and phase separation. Subsequently, it was purified by silica gel chromatography and high performance liquid chromatograph (HPLC). As a result, pure prodigiosin was identified by structural studies as a pigment. Also, this downstream procedure that uses the integrated bioreactor can be applied to the direct production and purification of other prodigiosin analogues and hydrophobic alkaloid compounds from several microorganisms.
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Moon HW, Shin S, Kim HY, Kim YR, Cho HI, Yoon SS, Park S, Kim BK, Chun H, Kim HC, Park CJ, Min YH, Lee DS. Therapeutic use of granulocyte-colony stimulating factor could conceal residual malignant cells in patients with AML1/ETO+ acute myelogenous leukemia. Leukemia 2006; 20:1408-13. [PMID: 16791271 DOI: 10.1038/sj.leu.2404286] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We have experienced a number of cases of AML1/ETO+ acute myelogenous leukemia that showed remission based on bone marrow (BM) morphological criteria, but that revealed clonal abnormalities in most cells by fluorescence in situ hybridization (FISH). Interestingly, most of these cases had AML with AML1/ETO rearrangement. The malignant cells were differentiated and considered mature cells after granulocyte-colony stimulating factor (G-CSF) treatment. To clarify the possible mechanisms underlying this phenomenon, we investigated the expression levels of G-CSFR in AML cells with AML1/ETO rearrangement by flow cytometry and real-time polymerase chain reaction (PCR). The number of AML1/ETO+ cells expressing G-CSFR at baseline was significantly higher than that of AML1/ETO- AML cells (2673 vs 522). In addition, the G-CSFR gene was more highly expressed in AML1/ETO+ cells than in AML1/ETO- cells by real-time PCR. This study reveals that cases showing remission after treatment with G-CSF mostly had leukemia with AML1/ETO rearrangement. This finding might be explained by the higher expression of G-CSF receptor in AML1/ETO+ cells than in AML1/ETO- cells. We recommend that remission should be confirmed by FISH, because malignant clones can be differentiated and masked in morphological examination or chromosome test, especially for AML with AML1/ETO rearrangement.
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Lee JH, Na Y, Song HE, Kim D, Park BH, Rho SH, Im YJ, Kim MK, Kang GB, Lee DS, Eom SH. Crystal structure of the apo form of D-alanine: D-alanine ligase (Ddl) from Thermus caldophilus: A basis for the substrate-induced conformational changes. Proteins 2006; 64:1078-82. [PMID: 16779845 DOI: 10.1002/prot.20927] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Shin YW, Kwon JS, Kim JJ, Kang DH, Youn T, Kang KW, Kang E, Lee DS, Lee MC. Altered neural circuit for working memory before and after symptom provocation in patients with obsessive-compulsive disorder. Acta Psychiatr Scand 2006; 113:420-9. [PMID: 16603033 DOI: 10.1111/j.1600-0447.2005.00709.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE The authors compared the neural circuits recruited for working memory (WM) in obsessive-compulsive disorder (OCD) patients both at a neutral state and at a symptom provoked state. METHOD Twelve OCD patients, and 12 age-, and sex-matched healthy subjects underwent [(15)O]H(2)O positron emission tomography (PET) scanning, while performing WM task. In the patients, the tasks were performed both in the neutral and in the symptom provoked states. RESULTS In the OCD patients, the right caudate and the right superior parietal cortex (rSPC) displayed activations for WM at the neutral state, while the right cingulate cortex and rSPC displayed activations for WM at the symptom provoked state. Path analysis revealed that the activity of the caudate and orbitofrontal cortex was altered according to the interaction between WM and symptom provocation. CONCLUSION The interaction between symptom provocation and WM occurring in the fronto-striatal system may hold the key to the neurobiology of OCD.
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Lee SW, Kim B, Lee DS, Lee HJ, Park JG, Ahn SJ, Campbell EEB, Park YW. Fabrication and mechanical properties of suspended one-dimensional polymer nanostructures: polypyrrole nanotube and helical polyacetylene nanofibre. NANOTECHNOLOGY 2006; 17:992-996. [PMID: 21727371 DOI: 10.1088/0957-4484/17/4/025] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Mechanical properties of suspended quasi-one-dimensional polymer nanostructures were investigated using atomic force microscopy (AFM). A recently developed new acid-free etch method combined with electron beam lithography was used to fabricate suspended polypyrrole (PPy) nanotubes and helical polyacetylene (HPA) nanofibres. The elastic modulus of each suspended structure was obtained by AFM force-distance measurements. The estimated modulus value of the PPy nanotube (HPA nanofibre) was 0.96 GPa (0.5 GPa). Using this acid-free method, all-organic flexible NEMS devices can be fabricated in the future.
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Bae J, Kim KH, Kim D, Choi Y, Kim JS, Koh S, Hong SI, Lee DS. A practical enzymatic synthesis of UDP sugars and NDP glucoses. Chembiochem 2006; 6:1963-6. [PMID: 16206230 DOI: 10.1002/cbic.200500183] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Kim SJ, Shin HH, Park SY, Lee DS, Lee EA, Cho SD, Cho HR, Miyazawa K, Choi HS. Induction of MMP-13 expression by soluble human glucocorticoid-induced tumor necrosis factor receptor in fibroblast-like synovial cells. Osteoarthritis Cartilage 2006; 14:146-53. [PMID: 16242974 DOI: 10.1016/j.joca.2005.08.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2005] [Accepted: 08/30/2005] [Indexed: 02/02/2023]
Abstract
OBJECTIVE We tested the hypothesis that human glucocorticoid-induced tumor necrosis factor receptor (hGITR/TR11) expressed on the surface of activated CD4(+) T cells is responsible for up-regulating the production of matrix metalloproteinase (MMP)-13 by fibroblast-like synoviocytes (FLSs). METHODS The level of MMP-13 was measured by Western blot and reverse transcriptase polymerase chain reaction (RT-PCR). Expressions of hGITR ligand (hGITRL) on the surface of FLSs and hGITR on the surface of human CD4(+) T cells were analyzed by flow cytometry and RT-PCR. Neutralizing antibodies (Abs) were used to block hGITRL and hGITR on the surface of FLSs and human CD4(+) T cells, respectively. Human CD4(+) T cells were cocultured with FLSs to facilitate interaction between hGITR on CD4(+) T cells and hGITRL on FLSs. RESULTS Soluble hGITR (shGITR) stimulated FLSs to produce MMP-13, and blockade of hGITRL reduced this effect. Direct contact between activated CD4(+) T and FLSs also induced the production of MMP-13, and neutralization of hGITR on activated CD4(+) T cells during coculture decreased the amount of MMP-13 produced by FLSs. CONCLUSION shGITR stimulated FLSs to produce MMP-13 via a signal through hGITRL. Direct contact between activated CD4(+) T cells and FLSs facilitated hGITR-hGITRL interaction, and resulted in inducing MMP-13. This effect may increase tissue destruction in chronic inflammation such as rheumatoid arthritis (RA).
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Lee SH, Kim KK, Rhyu IC, Koh S, Lee DS, Choi BK. Phenol/water extract of Treponema socranskii subsp. socranskii as an antagonist of Toll-like receptor 4 signalling. Microbiology (Reading) 2006; 152:535-546. [PMID: 16436441 DOI: 10.1099/mic.0.28470-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Treponema socranskii is one of the most frequently found oral spirochaetes in periodontitis and endodontic infections. LPS or glycolipids from bacteria are potent stimulators of innate immune and inflammatory systems. In this study the bioactivity of a phenol/water extract from T. socranskii subsp. socranskii (TSS-P) was analysed. TSS-P showed minimal endotoxicity and no inducing potential for proinflammatory cytokines (TNF-α and IL-8) or for intercellular adhesion molecule-1 (ICAM-1) in human monocyte cell line THP-1 cells and primary cultured human gingival fibroblasts. Rather, it inhibited ICAM-1 expression and IL-8 secretion from cells stimulated by the LPS of Escherichia coli and Actinobacillus actinomycetemcomitans, which are known to be Toll-like receptor 4 (TLR4) agonists. However, this antagonistic activity was not shown in cells stimulated by peptidoglycan or IL-1β. As its antagonistic mechanism, TSS-P blocked the binding of E. coli LPS to LPS-binding protein (LBP) and CD14, which are molecules involved in the recruitment of LPS to the cell membrane receptor complex TLR4–MD-2 for the intracellular signalling of LPS. TSS-P itself did not bind to MD-2 or THP-1 cells, but inhibited the binding of E. coli LPS to MD-2 or to the cells in the presence of serum (which could be replaced by recombinant human LBP and recombinant human CD14). The results suggest that TSS-P acts as an antagonist of TLR4 signalling by interfering with the functioning of LBP/CD14.
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