• 한국미생물·생명공학회지
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• 제22권2호
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• pp.134-142
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• 1994

The neucleotide sequences of the xylA gene encoding $\beta $-xylosidase of Bacillus stearothermophilus and is its flanking regions were datermined. Three open reading frame(ORFs) were found, one of which(ORF1) appeared to code for the $\beta $-xylosidase. The 1830 base pair ORF1 encoded 609 amino acids starting from a TTG initiation codon. The molecular weight deduced from the nucleotide sequence(68 KD) was in agreement with that estimated by SDS-polyacrylamide gel electrophoresis of the purified enzyme(66 KD). The Shine-Dalgarno sequence(5'-AGGAGG-3') was found 11 bp upstream of the initiation codon. Further 15 bp upstream, there observed a potential transcription initiation signals. The putative -10 sequence(CATAAT) and -35 sequence(TTGTTA) coresponded closely to the consensus sequences for Bacillus subtilis RNA polymerase with major sigma factor. The guanine-plus-cytosine content of the coding region of the xylA gene was 56mol% while that of the third position of the codons was 63 mol%. Based on the comparison with the amino acid sequences of several other carbohydrate degrading enzymes, two conserved regions, possibly participating in the catalytic mechamism of $\beta $-xylosidase xylA, were identified in 278-298 and 329-350 regions of the translated xylA gene. The nucleotide sequence of the xylA was found to exhibit no homology to any other genes so far reproted.

• Journal of Microbiology and Biotechnology
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• 제10권4호
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• pp.564-567
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• 2000

A recombinant Saccharomyces cerevisiae, transformed with the genes encoding xylose reductase (XYL1) and xylitol dehydrogenase (XYL2) orginated from Pichia stipitis CBS 5776, was developed to directly convert xylose to ethanol. A fed-batch fermentation with the recombinant yeast produced 8.7 g ethanol/l with a yield of 0.13 g ethanol/g xylose consumed.

• 미생물학회지
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• 제33권2호
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• pp.92-96
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• 1997

Pseudomonas sp. strain DJ77로부터 클로닝한 catechol 분해와 관련된 phnDEFG 유전자들이 존재하는 pHENX7에서 phnF 유전자의 염기서열을 밝혔다. Extradiol dioxygenase 유전자인 phnE와, 2-hydroxymuconic semialdehyde dehydrogenase를 생산하는 phnG 유전자 사이에 존재하는 유전자 phnF는 432 bps로 된 하나의 open reading frame(ORF)으로 존재하였고, 여기서 유추한 아미노산은 143개로 분자량 13,859 dalton의 polypeptide를 만들어 내고 있다. phnF 유전자는 Sphingomonas sp. strain HV3 catE 유전자 부위와 sphingomonas yanoikuyae B1의 xylE와 xylG 사이에 존재하는 ORF 부위의 염기서열과 각각 99%, 68.6%의 상동성을 가지고 있었다. 또한 PhnF 단백질의 아미노산서열은 citrobacter freundii DSM30040의 orfY 부위의 아미노산서열과 62.3%의 상동성이 있었다.

• 미생물학회지
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• 제34권3호
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• pp.115-119
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• 1998

Pseudomonas sp. DJ77로부터 전보에서 클로닝한 pHENX7의 하류방향으로 약 3kb 정도를 포함하는 pYCS500을 클로닝하였다. PYCS500의 제한효소지도를 작성하고 부분적으로 염기서열을 분석한 결과 465 bp의 HindIII-ClaI절편에서 282 bp로 이루어진 하나의 open reading frame(ORF)을 발견하였다. phnM으로 명명된 이 ORF는 93개의 아미노산으로 구성된 polypeptide를 암호화하고 있었으며 계산된 분자량은 10,008 Da이었다. PhnM은 NahT, XylT, DmpQ, AtdS, PhlG, PhhQ, TbuW 등 plant-type ferredoxin 형태의 단백질과 37.7%-53.9%의 상동성을 나타내었으며 이들이 공통적으로 가지고 있는 motif가 일치하였다.

• Journal of Microbiology and Biotechnology
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• 제32권2호
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• pp.187-194
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• 2022

Two α-ʟ-arabinofuranosidases (BfdABF1 and BfdABF3) and a β-ᴅ-xylosidase (BfdXYL2) genes were cloned from Bifidobacterium dentium ATCC 27679, and functionally expressed in E. coli BL21(DE3). BfdABF1 showed the highest activity in 50 mM sodium acetate buffer at pH 5.0 and 25℃. This exo-enzyme could hydrolyze p-nitrophenyl arabinofuranoside, arabino-oligosaccharides (AOS), arabinoxylo-oligosaccharides (AXOS) such as 3²-α-ʟ-arabinofuranosyl-xylobiose (A³X), and 2³-α-ʟ-arabinofuranosyl-xylotriose (A²XX), whereas hardly hydrolyzed polymeric substrates such as debranched arabinan and arabinoxylans. BfdABF1 is a typical exo-ABF with the higher specific activity on the oligomeric substrates than the polymers. It prefers to α-(1,2)-ʟ-arabinofuranosidic linkages compared to α-(1,3)-linkages. Especially, BfdABF1 could slowly hydrolyze 2³,3³-di-α-ʟ-arabinofuranosyl-xylotriose (A²⁺³XX). Meanwhile, BfdABF3 showed the highest activity in sodium acetate at pH 6.0 and 50℃, and it has the exclusively high activities on AXOS such as A³X and A²XX. BfdABF3 mainly catalyzes the removal of ʟ-arabinose side chains from various AXOS. BfdXYL2 exhibited the highest activity in sodium citrate at pH 5.0 and 55℃, and it specifically hydrolyzed p-nitrophenyl xylopyranoside and xylo-oligosaccharides (XOS). Also, BfdXYL2 could slowly hydrolyze AOS and AXOS such as A³X. Based on the detailed hydrolytic modes of action of three exo-hydrolases (BfdABF1, BfdABF3, and BfdXYL2) from Bf. dentium, their probable roles in the hemiceullose-utilization system of Bf. dentium are proposed in the present study. These intracellular exo-hydrolases can synergistically produce ʟ-arabinose and ᴅ-xylose from various AOS, XOS, and AXOS.

• Journal of Microbiology
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• 제43권spc1호
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• pp.110-117
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• 2005

Salmonella enterica serovar Typhimurium causes human gastroenteritis and a systemic typhoid-like infection in mice. A critical virulence determinant of Salmonella is the ability to invade mammalian cells. The expression of genes required for invasion is tightly regulated by environmental conditions and a variety of regulatory genes. The hilA regulator encodes an OmpR/ToxR family transcriptional regulator that activates the expression of invasion genes in response to both environmental and genetic regulatory factors. Work from several laboratories has highlighted that regulation of hilA expression is a key point for controlling expression of the invasive phenotype. A number of positive regulators of hilA expression have been identified including csrAB, sirA/barA, pstS, hilC/sirC/sprA, fis, and hilD. HilD, an AraC/XylS type transcriptional regulator, is of particular importance as a mutation in hilD results in a 14-fold decrease in chromosomal hilA::Tn5lacZY-080 expression and a 53-fold decrease in invasion of HEp-2 cells. It is believed that HilD directly regulates hilA expression as it has been shown to bind to hilA promoter sequences. In addition, our research group, and others, have identified genes (hilE, hha, pag, and lon) that negatively affect hilA transcription. HilE appears to be an important Salmonella-specific regulator that plays a critical role in inactivating hilA expression. Recent work in our lab has been directed at understanding how environmental signals that affect hilA expression may be processed through a hilE pathway to modulate expression of hilA and the invasive phenotype. The current understanding of this complex regulatory system is reviewed.