• 미생물학회지
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• 제33권1호
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• pp.22-26
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• 1997

Pseudomonas sp. DJ77의 게놈 library로부터 phenanthrene 분해에 관련된 유전자를 포함하는 약 5-kb의 XhoI 절편을 pBLUESCRIPT SK(+)로 클로닝하였으며, 이 재조합 plasmid를 pUPX5라 명명하였다. 이 재조합 균주에 catechol과 2,3-dihydroxybiphenyl 용액을 분무하면 노란색의 meta-cleavage 화합물이 생성됨을 관찰 할 수 있었다. 그리고 효소 활성을 측정한 결과 catechol에서보다 2,3-dihydroxybiphenyl에 더 큰 활성을 나타냈다. 이 부분에 존재하는 2,3-dihydroxybiphenyl 1,2-dioxygenase 유전자의 위치를 결정하고, 이 유전자를 phnQ라 명명하였다.

• 한국미생물·생명공학회지
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• 제21권2호
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• pp.150-156
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• 1993

The 2,3-dihydroxybiphenyl(2,3-DHBP) dioxygenase, the product of pcbC gene, was purified from the biphenyl and 4-chlorobiphenyl degrading Pseudomonas sp. DJ-12 by the methods of acetone precipitation, DEAE-Sephadex A-50 ion exchange chromatography, and Sephadex G-150 gel filtration chromatography. The enzyme was estimated to be about 260 kilodaltons in molecular weight and to be consisted of eight subunits. The Km value of the enzyme was 61 nM to 2,3-DHBP and the highest activity of the enzyme was observed at pH 8 and 30C.

• BMB Reports
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• 제32권4호
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• pp.399-404
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• 1999

2,3-Dihydroxybiphenyl 1,2-dioxygenase (2,3-DHBD), which catalyzes the ring meta-cleavage of 2,3-dihydroxybiphenyl, is encoded by the phnQ gene of biphenyl- and phenanthrene-degrading Pseudomonas sp. strain DJ77. We determined the nucleotide sequence of a DNA fragment of 1497 base pairs which included the phnQ gene. The fragment lncluded an open reading frame of 903 base pairs to accommodate the enzyme. The predicted amino acid sequence of the enzyme subunit consisted of 300 residues. In front of the gene, a sequence resembling an E. coli promoter was identified, which led to constitutive expression of the cloned gene in E. coli. The deduced amino acid sequence of the PhnQ enzyme exhibited 85.6% identity with that of the corresponding enzyme in Sphingomonas yanoikuyae Q1 (formerly S. paucimobilis Q1) and 22.1% identity with that of catechol 1,2,3-dioxygenase from the same DJ77 strain. PhnQ showed broader substrate preference than previously-cloned PhnE, catechol 2,3-dioxygenase. Ten amino acid residues, considered to be important for the role of extradiol dioxygenases, were conserved.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2001년도 추계학술대회
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• pp.16-25
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• 2001

A genomic library of biphenyl-degrading strain Comamonas sp. SMN4 was constructed by using the cosmid vector pWE15 and introduced into Escherichia coli. Of 1,000 recombinant clones tested, two clones that expressed 2,3-dihydroxybiphenyl 1,2-dioxygenase activity were found (named pNB 1 and pNB2). From pNB1 clone, subclone pNA210, demonstrated 2,3-dihydroxybiphenyl 1,2-dioxygenase activity, is isolated. 2,3-Dihydroxybiphenyl 1,2-dioxygenase (23DBDO, BphC) is an extradiol-type dioxygenase that involved in third step of biphenyl degradation pathway. The nucleotide sequence of the Comamonas sp. SMN4 gene bphC, which encodes 23DBDO, was cloned into a plasmid pQE30. The His-tagged 23DBDO produced by a recombinant Escherichia coli, SG 13009 (pREP4)(pNPC), and purified with a Ni-nitrilotriacetic acid resin affinity column using the His-bind Qiagen system. The His-tagged 23DBDO construction was active. SDS-PAGE analysis of the purified active 23DBDO gave a single band of 32 kDa; this is in agreement with the size of the bphC coding region. The 23DBDO exhibited maximum activity at pH 9.0. The CD data for the pHs, showed that this enzyme had a typical a-helical folding structures at neutral pHs ranged from pH 4.5 to pH 9.0. This structure maintained up to pH 10.5. However, this high stable folding strucure was converted to unfolded structure in acidic region (pH 2.5) or in high pH (pH 12.0). The result of CD spectra observed with pH effects on 23DBDO activity, suggested that charge transition by pH change have affected change of conformational structure for 23DBDO catalytic reaction. The $K_m$ for 2,3-dihydroxybiphenyl, 3-metylcatechol, 4-methylcatechol and catechol was 11.7 $\mu$M, 24 $\mu$M, 50 mM and 625 $\mu$M.

• 한국미생물·생명공학회지
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• 제24권6호
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• pp.657-663
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• 1996

Pseudomonas sp. P20 isolated from the polluted environment is capable of degrading biphenyl and 4-chlorobiphenyl. The pcbABCD genes responsible for degradation of biphenyl and 4-chlorobiphenyl were cloned using pBluescript SK(+) from the chromosomal DNA of Pseudomonas sp. P20 to construct pCK1 and pCK102, harbouring pcbABCD and pcbCD, respectively. The 2, 3-DHBP dioxygenase gene, pcbC, was cloned again from pCK102 by using pKT230 which is known as a shuttle vector and pKK1 hybrid plasmid was constructed. The E. coli KK1 transformant obtained by transforming the pKK1 into E. coli XL1-Blue showed 2, 3-DHBP dioxygenase activity. The specific 2, 3-DHBP dioxygenase activity of E. coli KK1 was similar to that of the E. coli CK102, but much higher than those of the natural isolates, Pseudomonas sp. DJ-12 and Pseudomonas sp. P20.

• Journal of Microbiology and Biotechnology
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• 제13권4호
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• pp.487-494
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• 2003

2,3-Dihydroxybiphenyl 1,2-dioxygenase (23DBDO), an enzyme of the biphenyl biodegradation pathway encoded by the bphC gene of Comnmonas sp. SMN4, was expressed and purified using column chromatographies. SDS-PAGE of purified 23DBDO showed a single band with a molecular mass of 32 kDa, which was consistent with the data from the gel filtration chromatography (GFC). The purified enzyme exhibited a maximum 23DBDO activity at pH 9.0 and was stable at pH 8.0. The enzyme showed maximum activity at $40^{\circ}C$ and maintained activity at $30^{\circ}C$ for 24 h. Kinetic parameters represented by Michaelis-Menten constants such as $K_m\;and\;V_{max}$ values for various substrates were determined by Lineweaver-Burk plots: The purified enzyme 23DBDO from Comamonas sp. SMN4 had the highest catalytic activity for 2,3-dihydroxybiphenyl and 3-methylcatechol, and had very poor activity with catechol and 4-methylcatechol.

• 한국미생물·생명공학회지
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• 제24권3호
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• pp.282-289
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• 1996

2,3-DHBP dioxygenase was purified from E. coli CK1092 carrying the pcbC gene, which was cloned from 4-chlorobiphenyl-degrading Pseudomonas sp. P20. Purification of this enzyme was done by acetone precipitation, DEAE- Sephadex A-25 ion exchange chromatography, and preparative gel electrophoresis. The molecular weight of subunit was 34 kDa determined by SDS-PAGE, and that of native enzyme was about 270 kDa. It suggests that this enzyme consist of eight identical subunits. This enzyme was specifically active against only 2,3-DHBP as a substrate with 18 $\mu$M of Km value, but not catechol, 3-methylcatechol, 4-methylcatechol and 4-chlorocatechol. The optimal pH and temperature of 2,3-DHBP dioxygenase were pH 8.0 and 40-60$\circ$C. The enzyme was inhibited by Cu$^{2+}$, Fe$^{2+}$ and Fe$^{3+}$ ions, and was inactivated by H$_{2}$0$_{2}$2 and EDTA. The lower concentrations of some organic solvents such as acetone and ethanol don't stabilize the activity of 2,3-DHBP dioxygenase. The enzyme was completely inactivated by adding the reagents such as N-bromosuccinimide, iodine and p- diazobenzene sulfonic acid.

• 미생물학회지
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• 제34권1_2호
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• pp.20-25
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• 1998

PCBs를 분해하는 Pseudomonas sp. P20 균주의 pcbC gene이 재조합 된 E. coli CK1092 균주를 이용하여 2,3-dihydroxybiphenyl dioxygenase 생산에 미치는 배양조건을 검토하였다. E. coli CK1092를 2% sucrose가 포함된 LB 배지를 기본배지로 하여 질소원, 금속이온 등의 영향을 조사한 결과, $Fe^{3+}$와 $Fe^{2+}$이 $10^{-5}M$의 농도일때 효소생산이 증가되었으며 배양최적온도는 $37^{\circ}C$, 배양초기 pH 7.0일때 효소생산이 우수하였다. 배양조에서의 배양조건은 초기 pH 7.0, 통기량 1 v/v/m, 교반속도 200rpm에서 가장 효소생성이 우수하였다.

• Journal of Microbiology
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• 제35권2호
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• pp.141-148
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• 1997

Alcaligenes xylosoxydans strain SMN3 capable of utilizing biphenyl grew not only on phenol, and benzoate, but also on salicylate. Catabolisms of biphenyl and salicylate appear to be interrelated since benzoate is a common metabolic intermediate of these compounds. Enzyme levels in the excatechol 2. 3-dioxygenas which is meta-cleavage enzyme of catechol, but did not induce catechol 1, 2-dioxygenase. All the oxidative enzymes of biphenyl and 2, 3,-dihydroxybiphenyl (23DHBP) were induced when the cells were grown on biphenyl and salicylate, respectively. Biphenyl and salicylate could be a good inducer in the oxidation of biphenyl and 2, 3-dihydroxybiphenyl. The two enzymes for the degradation of biphenyl and salicylate were induced after growth on either biphenyl or salicylate, suggesting the presence of a common regulatory element. However, benzoate could not induce the enzymes responsible for the oxidation of these compounds. Biphenyl and salicylate were good inducers for indigo formation due to the activity of biphenyl dioxygenase. These results suggested that indole oxidation is a property of bacterial dioxygenase that form cis-dihydrodiols from aromatic hydrocarbon including biphenyl.

• 미생물학회지
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• 제32권1호
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• pp.40-46
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• 1994

Polychlorinaed biphenyls(PCBs) 와 biphenyl을 분해하는 Pseudomonas sp. DJ-12에서는 그 초기 분해과정에 pcb ABCD 유전자들이 관여하고 있음이 밝혀졌다. 그 중 pcbCD와 pcdD 유전자를 E. coli XL1-Blue에 클로닝하여 E. coli CU103 과 CU105 균주를 각각 제조하였다. E. coli CU103은 2,3-dehydroxybuphenyl dioxygenase(2,3-DHBP)와 meta-cleavage compound(MCP) hydrolase를 생성하여 2,3-dihydroxybiphenyl을 benzoate로 변환시켜 주었다. E. coli CU1 과 CU103 에서 pcbC 유전자의 산물인 2,3-DHBP dioxygense의 활성도는 Pseudomonas sp. DJ-12에서 보다 약 17배 높았으며, E. coli CU105에서 pcbD의 산물인 MCP hydrolase는 약 3배 더 높게 나타났다.