• Proceedings of the Korean Society of Toxicology Conference
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• 2002.11b
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• pp.42-58
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• 2002

Acute Cd exposure produces hepatotoxicity, whereas chronic Cd exposure produces nephrotoxicity, hematotoxicity, immunotoxicity and bone damage. Previous experiments suggest that the low-molecular-weight, metal-binding protein metallothionein (MT) in liver protects against liver injury, but is responsible for the kidney injury observed after chronic Cd exposure.(omitted)

• Bulletin of the Korean Chemical Society
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• v.26 no.12
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• pp.1911-1920
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• 2005

Effective artificial metalloproteases have been designed by using cross-linked polystyrene as the backbone. Artificial active sites comprising Cu(II) complexes as the catalytic site and other metal centers or organic functionalities as binding sites were synthesized. The activity of Cu(II) centers for peptide hydrolysis was greatly enhanced on attachment to polystyrene. By placing binding sites in proximity to the catalytic centers, the ability to hydrolyze a variety of protein substrates at selected cleavage sites was improved. Thus far, the most advanced immobile artificial proteases have been obtained by attaching the aldehyde group in proximity to the Cu(II) complex of cyclen.

• Journal of Microbiology and Biotechnology
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• v.26 no.3
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• pp.530-539
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• 2016

Bacterial light-oxygen-voltage-sensing photoreceptor-derived flavin mononucleotide (FMN)-based fluorescent proteins act as a promising distinct class of fluorescent proteins utilized for various biomedical and biotechnological applications. The key property of its independency towards oxygen for its chromophore maturation has greatly helped this protein to outperform the other fluorescent proteins such as GFP and DsRed for anaerobic applications. Here, we describe the feasibility of FMN-containing fluorescent protein FbFP as a metal-sensing probe by measuring the fluorescence emission changes of a protein with respect to the concentration of metal ions. In the present study, we demonstrated the mercury-sensing ability of FbFP protein and the possible amino acids responsible for metal binding. A ratiometric approach was employed here in order to exploit the fluorescence changes observed at two different emission maxima with respect to Hg²⁺ at micromolar concentration. The engineered variant FbFP_C56I showed high sensitivity towards Hg²⁺ and followed a good linear relationship from 0.1 to 3 μM of Hg²⁺. Thus, further engineering with a rational approach would enable the FbFP to be developed as a novel and highly selective and sensitive biosensor for other toxic heavy metal ions as well.

• Proceedings of the Korean Biophysical Society Conference
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• 2001.06a
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• pp.52-52
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• 2001

Nickel-binding protein (NBP1) was purified from the crude extract of Streptomyces seoulensis using Ni$^{2＋}$-charged metal chelate affinity chromatography. The molecular mass of NBPI determined on SDS-PAGE was 38kDa. An approximately 3 kb DNA fragment containing the structural gene for NBP1 was cloned from lEMBL3 genomic library of S. seoulensis using a DNA fragment PCR-amplified with the primers designed from N-terminal and internal amino acid sequences of NBP1.(omitted)

• Proceedings of the Korean Environmental Health Society Conference
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• 2004.06a
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• pp.87-91
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• 2004

Immunohistochemical and ultrastructural experiments were conducted to find out heavy metal accumulation in some selected organs such as the kidney, the hepatopancreas, and the gills of the Antarctic Clam Laternula elliptica According to the immunohistochemical study the subject organs of the clam showed reactions indicating the presence of MT(metallothionein), a metal-binding protein involved in metal detoxifying process. Examination under the transmission electron microscope also revealed that other ligands(e.g. metal-rich granules in the kidney) may play a role in metal accumulating and detoxifying process in L. elliptica. In the artificial exposure of the clam to Cd, it showed immediate subcellular responses, suggesting that this species can be used as rapid and efficient bioindicators for Cd exposure in natural environment.

• Journal of Microbiology and Biotechnology
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• v.28 no.2
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• pp.323-329
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• 2018

In Escherichia coli, the transcription of genes related to metal homeostasis is activated by the presence of target metals. The promoter regions of those genes can be fused with reporter genes to generate whole-cell bioreporters (WCBs); these organisms sense the presence of target metals through reporter gene expression. However, the limited number of available promoters for sensing domains restricts the number of WCB targets. In this study, we have demonstrated an alternative method to generate novel WCBs, based on the notion that since the sensing mechanisms of WCBs are related to metal transportation systems, their properties can be modulated by disrupting metal homeostasis. Mutant E. coli strains were generated by deleting the znt-operon genes zntA, which encodes a zinc-export protein, and zntR, which encodes a znt-operon regulatory protein, to investigate the effects on the metal-sensing properties of WCBs. Deletion of zntA increased the sensitivity but abolished the selectivity of cadmium-sensing WCBs, whereas arsenic-sensing WCBs gained sensitivity toward cadmium. When zntR was deleted, cadmium-sensing WCBs lost the ability to detect cadmium, and this was recovered by introducing exogenous zntR. In addition, the metal-binding site of ZntR was genetically engineered to modulate metal selectivity. This study provides a valuable platform for the development of novel E. coli-based WCBs.

• Animal cells and systems
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• v.7 no.3
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• pp.173-186
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• 2003

The transition metal cadmium is a serious occupational and environmental toxin. To inhibit cadmium-induced damage, cells respond by increasing the expression of genes that encode stress-responsive proteins. The metal-regulatory transcription factor 1 (MTF-1) is a key regulator of heavy-metal induced transcription of metallothionein-I and II and other genes in mammals and other metazoans. Transcriptional activation of genes by MTF-1 is mediated through binding to metal-responsive elements in the target gene promoters. Phosphorylation of MTF-1 plays a critical role in the cadmium-inducible transcriptional activation of metallothionein and other responses. Studies using inhibitors indicate that multiple kinases and signal transduction cascades, including those mediated by protein kinase C, tyrosine kinase and casein kinase II, are essential for cadmium-mediated transcriptional activation. In addition, calcium signaling is also involved in regulating metal-activated transcription. In several species, cadmium induces heat shock genes. Recently much progress has been made in elucidating the cellular machinery that regulates this metal-inducible gene expression. This review summarizes these recent advances in understanding the role of some known cadmium-responsive genes and the molecular mechanisms that activate metal-responsive transcription factor, MTF-1.

• BMB Reports
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• v.39 no.5
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• pp.595-606
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• 2006

Metallothioneins are a group of low molecular mass and cysteine-rich metal-binding proteins, ubiquitously found in most living organisms. They play an important role in maintaining intracellular metal homeostasis, eliminating metal toxification and protecting against intracellular oxidative damages. Analysis of complete rice genome sequences revealed eleven genes encoding putative metallothionein (OsMT), indicating that OsMTs constitute a small gene family in rice. Expression profiling revealed that each member of the OsMT gene family differs not only in sequence but also in their tissue expression patterns, suggesting that these isoforms may have different functions they perform in specific tissues. On the basis of OsMT structural and phylogenetic analysis, the OsMT family was classified as two classes and class I was subdivided into four types. Additionally, in this paper we also present a complete overview of this family, describing the gene structure, genome localization, upstream regulatory element, and exon/intron organization of each member in order to provide valuable insight into this OsMT gene family.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.426-427
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• 2005

This research describes a new constructing method of multifunctional biosensor using many kinds of biomaterials. A metal particle and an array was fabricated by photolithographic. Biomaterials were immobilized on the metal particle. The array and the particles were mixed in a buffer solution, and were arranged by magnetic force interaction and self-assembly. A quarter of total Ni dots were covered by the particles. The binding direction of the particles was controllable, and condition of particles was almost with Au surface on top. The particles were successfully arranged on the array. The biomaterial activities were detected by chemiluminescence and electrochemical methods.

• Korean Journal of Microbiology
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• v.47 no.2
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• pp.158-162
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• 2011

Amino acid sequence alignment shows that $\underline{P}$roteus $\underline{m}$irabilis $\underline{t}$ranscription $\underline{r}$egulator (PMTR) has cystein sequence homology at metal binding domain to CueR (copper resistance) protein, which conserves two cysteins (Cys 112 and Cys 120 in PMTR). Gel shift assay revealed that PMTR protein bound to promoter region of Escherichia coli copA (copper-translocating P-type ATPase) and Proteus mirabilis atpase (putative copper-translocating P-type ATPase) genes except that of E. coli zntA (zinc-translocating P-type ATPase) gene. DNase I protection experiment indicated that PMTR protein protected the region over -35 box and close to -10 box. DNase I hypersensitive bases were shown at C and A bases of labeled template strand and at G and C bases of labeled non-template strand of DNA. These hypersensitive bases were appeared in other metalloregulatory proteins of MerR family, which suggests protein-induced DNA bending.