• Korean Journal of Microbiology
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• v.36 no.1
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• pp.1-7
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• 2000

The genes involved in riboflavin synthesis (ribI, II, III, and IV) were found immediately downstream of luxG in the lux operon from Photobacterium species. The single stranded DNA containing the intergenic region of lux genes and rib genes from Photobacterium phosphoreum was fully protected by P. phosphoreum mRNA from the S1 nuclease mapping assay suggesting that a transcriptional terminator was not present in the region. In addition, the levels of riboflavin synthase activity in P. phosphoreum was increased during the development of bacterial bioluminescence in the same fashion as the luciferase and fatty acid reductase activities. Insertion of the Photobacterium leiognathi DNA extending from luxB to ribII, between a strong lux promoter and a reporter gene (chloramphenicol acetyltransferase, CAT) and transferred by conjugation into P. leiognathi, did not affect expression of reporter gene. Moreover the CAT gene was not expressed in an analogous construct missing the lux promoter indicating that a promoter was not present in this region. Based on the data here, it can be concluded that the lux genes and rib genes in Photobacterium species are under common regulation.

• Journal of Photoscience
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• v.11 no.1
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• pp.41-45
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• 2004

The key riboflavin synthesis genes are located immediately downstream of luxG in the lux operon from Photobacterium leiognathi. It is of interest that a site capable of forming a rho-independent terminator does not appear to be present between luxG and ribE in our previous data. These results raise the question of whether the transcription of lux and rib genes is integrated or not. In order to answer the question, in vivo transcriptional assay and Southern blot were examined. These studies demonstrate that neither transcriptional terminator nor promoter site is present in the intergenic region between of lux and rib genes as well as that the riboflavin genes are single copy in a chromosome of Photobacterium leiognathi.

• Korean Journal of Microbiology
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• v.32 no.2
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• pp.139-146
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• 1994

Protective effects on subcellular localization of Photobacterium leiognathi CuZnSOD(PSOD) were examined in Escherichia coli SOD mutant cells on the treatment of paraquat, heat shock $(37^{\circ}C{\to}42^{\circ}C{\to})$, hydrogen peroxide and copper sulfatem respectively. The physiological characteristics of the periplasmic and cytoplasmic PSOD localized differently are dependent on the conditions in this experiment. Cells expressing SOD periplasmically in the treatments of paraquat and $H_2O_2$ respectively were somewhat better protective effects cells expressiong SOD cytoplasmically at comparable level and SOD expression level showed, the most consistently important variable. However, this was reversed in the treatments of heat shock and $CuSO_4$, respectively.

• Korean Journal of Microbiology
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• v.52 no.4
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• pp.495-499
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• 2016

In order to identify the biochemical characteristics of LuxG, the luxG gene from bioluminescence bacteria of Photobacterium leiognathi ATCC 25521 was isolated by PCR-Amplification and inserted into pQE30 vector containing the T5 promoter and 6X His-tag system. The resulting recombinant plasmid was transformed into Escherichia coli to over-express the luxG gene and purify the gene product. The purified LuxG protein demonstrated ferric iron reductase activity and the kinetic parameters of $K_m$ and $V_{max}$ for FMN as well as the NADPH substrates of ferric iron reductase were determined, respectively.

• Bulletin of the Korean Chemical Society
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• v.31 no.4
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• pp.1017-1020
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• 2010

• Korean Journal of Microbiology
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• v.49 no.2
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• pp.205-210
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• 2013

Lumazine protein is a fluorescent protein isolated from the bioluminescent bacteria of Photobacterium species. To generate minimal size of lumazine protein with possessing fluorescent characteristic, the gene coding for the wild type N-terminal domain of lumazine protein (N-LumP 118) containing amino acids up to 118 from Photobacterium leiognathi was produced. In addition, the genes coding for the variant proteins of N-LumP 118, replaced with one tryptophan amino acid (N-LumP 118 V41W, S48W, T50W, D64W, and A66W), were also constructed by Polymerase Chain Reaction and Site Directed Mutagenesis. These proteins were expressed in Escherichia coli by transformation with recombinant plasmids and purified by 6X-His tagging system. Spectroscopic studies have show that the purified proteins are capable of binding to the fluorescent ligand 6,7-dimethyl-8-ribityllumazine, resulted in showing of fluorescent characteristic with the minimal size of protein. From these studies, the mutant proteins containing single tryptophan amino acid residue, possessing its own intrinsic flouophore character at the different position, will be able to the use as a probe for further studies to deduce their three dimensional structure and the binding modes.

• Journal of the Korean Chemical Society
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• v.64 no.4
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• pp.225-230
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• 2020

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1673-1678
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• 2013

Lumazine protein is a member of the riboflavin synthase superfamily and the intense fluorescence is caused by non-covalently bound to 6,7-dimethyl 8-ribityllumazine. To figure out the binding modes and the structure of the N-terminal domain of lumazine protein, the wild type of protein extending to amino acid 118 (N-LumP 118 Wt) and mutants of N-LumP 118 V41W, S48W, T50W, D64W, and A66W from Photobacterium leiognathi were purified. The biochemical properties of the wild type and mutants of N-LumP 118 proteins were analyzed by absorbance and fluorescence spectroscope. The peak of absorbance and fluorescence of lumazine ligand were shifted to longer wavelength on binding to N-LumPs. The observed absorbance value at 410 nm of lumazine bound to N-LumP 118 proteins indicate that one mole of N-LumP 118 proteins bind to one mole of ligand of lumazine. Fluorescence analysis show that the maximum peak of fluorescence of N-LumP S48W was shifted to the longest wavelength by binding with 6,7-dimethyl 8-ribityllumazine and was shown to the greatest quench effect by acrylamide among all tryptophan mutants.

• Korean Journal of Microbiology
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• v.30 no.6
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• pp.460-465
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• 1992

The effect of PSOD expression on lacZ-sodP fusion (pYK4) was explored in Escherichia coli sodA sodB mutants (QC774) under oxidative stress. In this system, although .betha.-galactosidase activity was not fully induced by isopropyl-1-thio-.betha.-galactosidase (IPTG) and was inhibited by glucose, functional PSOD was under lacZ promotor control and was induced by IPTC, lactose, PQ and copper isons, finally, the results show that higher PSOD expression leel was consistently importnat in defending against superoxide radicals.

• Korean Journal of Microbiology
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• v.45 no.4
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• pp.419-424
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• 2009

To provide the basis of biosensor based on the lux genes from bioluminescent bacteria of Photobacterium leiognathi and Vibrio harveyi, we test the expression of lux genes in several strains of Escherichia coli. The expression of the recombinant plasmid of PlXba.pT7-3, containing all lux genes requiring for light emission without adding substrate, in E. coli 43R was so strong to see the blue-green light in single colony as well as in the alginate immobilized cell. In addition, the light intensity was decreased by adding heavy metal ion such as cadmium and zinc ions. These result raise the possibility that a biosensor can be developed using the lux genes system.