• BMB Reports
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• v.38 no.2
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• pp.248-252
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• 2005

Dihydrolipoamide dehydrogenase (E3) catalyzes the reoxidation of dihydrolipoyl moiety of the acyltransferase components of three $\alpha$-keto acid dehydrogenase complexes and of the hydrogen-carrier protein of the glycine cleavage system. His-457 of Pseudomonas putida E3 is suggested to interact with the hydroxyl group of Tyr-18 of the other subunit and with Glu-446, a component in the last helical structure. To examine the importance of the suggested interactions in human E3 function, the corresponding residue of human E3, Asn-473, was substituted to Leu using site-directed mutagenesis. The E3 mutant was expressed in Escherichia coli and highly purified using an affinity column. Its E3 activity was decreased about 37-fold, indicating that Asn-473 residue was important to the efficient catalytic function of human E3. Its slightly altered spectroscopic properties implied that small conformational changes could occur in the E3 mutant.

• Korean Journal of Environmental Biology
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• v.22 no.4
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• pp.479-486
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• 2004

Phytoestrogens display estrogen-like activity because of their structural similarity to human estrogens and exhibit high affinity binding for the estrogen receptors (ERs). The prevalence of phytoestrogens in our diets and the biological effects that they may cause need to be fully examined. ER is the ancestral receptor from which all other steroid receptors have evolved. Although phytoestrogens serve specific signaling functions between the plants and insects, fungi, and bacteria, many chemical signals are often misinterpreted as estrogenic signals in non-target organisms such as vertebrates. There are no ERs in plants or in their most common partners, insects. However, Rhizobium soil bacteria have NodD proteins which is an intended target of phytoestrogen signaling and share genetic homology with the ER. These two evolutionarily distant receptors both recognize and respond to a shared group of chemical signals and ligands, including both agonists and antagonists. This review briefly summarizes estrogen and estrogen receptors, kinds of important phytoestrogens, their health effects as well as some of the evolutionary aspects of mechanism by which phytoestrogen mimics the endogenous ER signaling in our body.

• Bulletin of the Korean Mathematical Society
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• v.49 no.2
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• pp.395-409
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• 2012

In the study of homology cobordisms, knot concordance and link concordance, the following technical problem arises frequently: let ${\pi}$ be a group and let M ${\rightarrow}$ N be a homomorphism between projective $\mathbb{Z}[{\pi}]$-modules such that $\mathbb{Z}_p\;{\otimes}_{\mathbb{Z}[{\pi}]}M{\rightarrow}\mathbb{Z}_p{\otimes}_{\mathbb{Z}[{\pi}]}\;N$ is injective; for which other right $\mathbb{Z}[{\pi}]$-modules V is the induced map $V{\otimes}_{\mathbb{Z}[{\pi}]}\;M{\rightarrow}\;V{\otimes}_{\mathbb{Z}[{\pi}]}\;N$ also injective? Our main theorem gives a new criterion which combines and generalizes many previous results.

• BMB Reports
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• v.35 no.4
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• pp.437-441
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• 2002

Dihydrolipoamide dehydrogenase (E3) is a member of the pyridine nucleotide-disulfide oxidoreductase family. Thr residues are highly conserved. They are at the active site disulfide-bond regions of most E3s and other oxidoreductases,. The crystal structure of Azotobacter vinelandii E3 suggests that the hydroxyl group of Thr that are involved in the FAD binding interact with the adenosine phosphate of FAD. However, several prokaryotic E3s have Val instead of Thr. To investigate the meaning and importance of the Thr conservation in many E3s, the corresponding residue, Thr-44, in human E3 was substituted to Val by site-directed mutagenesis. The mutant’s E3 activity showed about a 2.2-fold decrease. Its UV-visible and fluorescence spectra indicated that the mutant might have a slightly different microenvironment at the FAD-binding region.

• Journal of Plant Biotechnology
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• v.5 no.4
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• pp.201-207
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• 2003

Tissue culture techniques arguably are an important approach for ex situ conservation of rare and endangered plant species. However, there is utmost importance on maintaining the genetic integrity of the introduced plants especially in tree species. To examine the genetic integrity of the micropropagated plants, we randomly screened few hardened plants of Syzygium travancoricum, a critically endangered tree taxon, using Randomly Amplified Polymorphic DNA (RAPD) markers. Twenty-three random. primers were tried and twenty-five polymorphic loci were identified. The dendrogram based on the Unweighted Pair-Group Method Arithmetic Average and Nei's similarity index depicted about 97% homology between the mother plants and micropropagated plants. Further, an attempt was made to reintroduce the micropropagated plants in the wild. Over three hundred small trees could be successfully established.

• Korean Journal of Microbiology
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• v.40 no.3
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• pp.226-229
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• 2004

Histone deacetylase (HDAC) removes acetyl group in lysine residue of histone protein, which is transferred by histone acetylase. HDAC is important in the stabilization and regulation of gene expression in eukaryotic organisms. PCR has been carried out to clone HDAC genes using cDNA library and genomic DNA as the templates from Ganoderma lucidum isolated in Korea. One 470 bp cDNA gene fragment, and 3 genomic HDAC fragments (585 bp, 589 bp, 630 bp) were amplified. When their deduced amino acid sequences were compared with other fungal HDACs, they showed 59-72％ homology.

• Genomics & Informatics
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• v.19 no.2
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• pp.18.1-18.8
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• 2021

G protein–coupled receptors (GPCRs), including olfactory receptors, account for the largest group of genes in the human genome and occupy a very important position in signaling systems. Although olfactory receptors, which belong to the broader category of GPCRs, play an important role in monitoring the organism's surroundings, their actual three-dimensional structure has not yet been determined. Therefore, the specific details of the molecular interactions between the receptor and the ligand remain unclear. In this report, the interactions between human olfactory receptor 1A1 and its odorant molecules were simulated using computational methods, and we explored how the chemically simple odorant molecules activate the olfactory receptor.

• The Journal of Natural Sciences
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• v.9 no.1
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• pp.19-24
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• 1997

Using the PCR(polymerase chain reaction method), gone 1 of phage K11 coding for K11 phage RNA polymerase has been cloned and expressed under the control of lac promoter. K11 phage RNA polymerase was conventionally purified through the DEAE-sephacel and Affigel blue column chromatographies. The 0.2-0.3 M $NH_4Cl$ fractions of DAEA-sephacel column chromatography showed K11 phage RNA polymerase activity and further purification with Affigel blue column chromatography showed nearly single protein band on SDS-polyacryl amide gel. K11 phage RNA polymerase, which is one of the T7 group phage RNA polymerase (E. coil phage T7, T3 and Salmonella tyhimurium phage SP6 RNA polymerase), shares high degrees of homology with the other T7 group phage RNA polymerase. Previously we constructed T7 and SP6 promoter variants and revealed promoter specificity of T7 and SP6 RNA polymerase (Lee and Kang, 1993). To investigate the promoter specificity of K11 RNA polymerase in vitro K11 promoter activity was measured with SP6 promoter variants. The SP6 promoter variant share highest degrees of sequence homology with K11 promoter sequence show strongest promoter activity.

• Animal Bioscience
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• v.34 no.8
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• pp.1403-1414
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• 2021

Objective: This study explored the mechanism of the Kelch-like erythroid cell-derived protein with CNC homology-associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway under conditions of zearalenone (ZEA)-induced oxidative stress in the duodenum of post-weaning gilts. Methods: Forty post-weaning gilts were randomly allocated to four groups and fed diets supplemented with 0, 0.5, 1.0, or 1.5 mg/kg ZEA. Results: The results showed significant reductions in the activity of the antioxidant enzymes total superoxide dismutase and glutathione peroxidase and increases the malondialdehyde content with increasing concentrations of dietary ZEA. Immunohistochemical analysis supported these findings by showing a significantly increased expression of Nrf2 and glutathione peroxidase 1 (GPX1) with increasing concentrations of ZEA. The relative mRNA and protein expression of Nrf2, GPX1 increased linearly (p<0.05) and quadratically (p<0.05), which was consistent with the immunohistochemical results. The relative mRNA expression of Keap1 decreased linearly (p<0.05) and quadratically (p<0.05) in the duodenum as the ZEA concentration increased in the diet. The relative mRNA expression of modifier subunit of glutamate-cysteine ligase (GCLM) increased quadratically (p<0.05) in all ZEA treatment groups and the relative mRNA expression of quinone oxidoreductase 1 (NQO1) catalytic subunit of glutamate-cysteine ligase decreased linearly (p<0.05) and quadratically (p<0.05) in the ZEA1.0 group and ZEA1.5 group. The relative protein expression of Keap1 and GCLM decreased quadratically (p<0.05) in the duodenum as the ZEA concentration increased in the diet, respectively. The relative protein expression of NQO1 increased linearly (p<0.05) and quadratically (p<0.05) in all ZEA treatment groups in the duodenum. Conclusion: These findings suggest that ZEA regulates the expression of key factors of the Keap1-Nrf2 signaling pathway in the duodenum, which enables resistance to ZEA-induced oxidative stress. Further studies are needed to examine the effects of ZEA induced oxidative stress on other tissues and organs in post-weaning gilts.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.1
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• pp.12-26
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• 2002

The phylogenetic relationships for 33 strains belonging to the genera Azorhizobium, Bradyrhizobium, Mesorhizobium, Rhizobium and Sinorhizobium were conducted by the sequence analyses of the ITS regions. The sequence homologies of these strains showed the high variations(28.0 - 94.9%). According to the phylogenetic analysis of ITS regions. 37 ITS clones from 33 strains of 32 species were classified into four groups. Group I included all strains of the genus Sinorhizobium as core members and R. giardinii as a peripheral member. The genus Rhizobium strains were clustered into group II which was very heterogeneous and the tree toplogy of this group were very unstable. Among the members of group II. the taxonomic position of R. radiobacter and R. rubi was not clearly identified on the basis of ITS I regions. R. undicola and R. vitis were remotely related with other Rhizobium strains including R. leguminosarum, R. galegae, R. gallicum, R. mongolense, R. tropici, R. hainanense, R. rhizogense and R. huautlense of group II were supposed to be loosely related to R. leguminosarum. While the stains of the genera Bradyrhizobium constituted group III with Azorhizobium caulindans, the strains of the genus Mesorhizobium formed group IV on the relatively high sequence homology level.