• BMB Reports
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• 제44권10호
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• pp.653-658
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• 2011

Sclerotinia sclerotiorum fungus has three endoxylanases induced by wheat bran. In the first part, a partial xylanase sequence gene (90 bp) was isolated by PCR corresponding to catalytic domains (${\beta}5$ and ${\beta}6$ strands of this protein). The high homology of this sequence with xylanase of Botryotinia fuckeliana has permitted in the second part to amplify the XYN1 gene. Sequence analysis of DNA and cDNA revealed an ORF of 746 bp interrupted by a 65 bp intron, thus encoding a predicted protein of 226 amino acids. The mature enzyme (20.06 kDa), is coded by 188 amino acid (pI 9.26). XYN1 belongs to G/11 glycosyl hydrolases family with a conserved catalytic domain containing $E_{86}$ and $E_{178}$ residues. Bioinformatics analysis revealed that there was no Asn-X-Ser/Thr motif required for N-linked glycosylation in the deduced sequence however, five O-glycosylation sites could intervene in the different folding of xylanses isoforms and in their secretary pathway.

• Journal of Microbiology and Biotechnology
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• 제17권8호
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• pp.1262-1270
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• 2007

Some hot springs located in the west of Turkey were investigated with respect to the presence of thermophilic microorganisms. Based on phenotyping characteristics and 16S rRNA gene sequence analysis, 16 of the isolates belonged to the genus Geobacillus and grew optimally at about $60^{\circ}C$ on nutrient agar. 16S rRNA gene sequence analysis showed that these isolates resembled Geobacillus species by ${\ge}97%$, but SDS-PAGE profiles of these 16 isolates differ from some of the other species of the genus Geobacillus. However, it is also known that analysis of 16S rRNA gene sequences may be insufficient to distinguish between some species. It is proposed that recN sequence comparisons could accurately measure genome similarities for the Geobacillus genus. Based on recN sequence analysis, isolates 11, IT3, and 12 are strains of G stearothermophilus; isolate 14.3 is a strain of G thermodenitrificans; isolates 9.1, IT4.1, and 4.5 are uncertain and it is required to make further analysis. The presence of xylanase and arabinofuranosidase activities, and their optimum temperature and pH were also investigated. These results showed that 7 of the strains have both xylanase and arabinofuranosidase activities, 4 of them has only xylanase, and the remaning 5 strains have neither of these activities. The isolates 9.1, 7.1, and 3.3 have the highest temperature optima ($80^{\circ}C$), and 7.2, 9.1, AO4, 9.2, and AO17 have the highest pH optima (pH 8) of xylanase. Isolates 7.2, AO4, AC15, and 12 have optimum arabinofuranosidase activities at $75^{\circ}C$, and only isolate AC15 has the lowest pH of 5.5.

• BMB Reports
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• 제38권1호
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• pp.17-23
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• 2005

During the screening of xylanolytic enzymes from locally isolated fungi, one strain BCC14405, exhibited high enzyme activity with thermostability. This fugal strain was identified as Aspergillus cf. niger based on its morphological characteristics and internal transcribed spacer (ITS) sequences. An enzyme with xylanolytic activity from BCC14405 was later purified and characterized. It was found to have a molecular mass of ca. 21 kDa, an optimal pH of 5.0, and an optimal temperature of $55^{\circ}C$. When tested using xylan from birchwood, it showed $K_m$ and $V_{max}$ values of 8.9 mg/ml and 11,100 U/mg, respectively. The enzyme was inhibited by $CuSO_4$, EDTA, and by $FeSO_4$. The homology of the 20-residue N-terminal protein sequence showed that the enzyme was an endo-1,4-$\beta$-xylanase. The full-length gene encoding endo-1,4-$\beta$-xylanase from BCC14405 was obtained by PCR amplification of its cDNA. The gene contained an open reading frame of 678 bp, encoding a 225 amino acid protein, which was identical to the endo-1,4-$\^{a}$-xylanase B previously identified in A. niger.

• Journal of Applied Biological Chemistry
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• 제61권1호
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• pp.59-67
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• 2018

본 연구는 경상남도 산청군 소재 경남과학기술대학교 학술림에서 채취한 토양으로부터 CMCase와 xylanase를 생산하는 3개의 Bacillus종을 분리하였다. API kit 분석과 16S rRNA 유전자 염기서열 분석을 통해 3개의 균 모두 Bacillus종에 속하였으며, Bacillus sp. EFL1, EFL2, EFP3로 명명하였다. Bacillus sp. EFL1, EFL2, EFP3의 최적 생장온도는 $37^{\circ}C$였으며, CMCase와 xylanase의 활성은 배양 후 12시간에 최고에 달하였다. Bacillus sp. EFL1의 CMCase 효소활성의 최적온도는 $50^{\circ}C$, pH는 5.0이었고, xylanase 효소활성의 최적온도는 $50^{\circ}C$, pH 6.0이었다. Bacillus sp. EFL2의 CMCase활성의 최적온도는 $60^{\circ}C$, pH는 5.0이었고, xylanase 효소활성의 최적온도는 $60^{\circ}C$였고, pH 3.0-9.0까지 비교적 높은 활성을 보였다. Bacillus sp. EFP3의 CMCase의 최적온도는 $50^{\circ}C$, pH는 5.0이었고, xylanase의 최적온도는 $50^{\circ}C$, pH 4.0이었다. Bacillus sp. EFL1, EFL2, EFP3의 CMCase는 모두 온도안정성이 낮았다. 또한 Bacillus sp. EFL1과 EFP3의 xylanase 역시 온도안정성이 낮았지만, Bacillus sp. EFL2의 xylanase는 온도안정성이 높았다.

• 한국미생물·생명공학회지
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• 제45권2호
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• pp.155-161
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• 2017

Paenibacillus woosongensis의 유전체 부분 염기서열로부터 유추된 xylanase 유전자를 PCR 증폭하여 클로닝하고 염기서열을 결정하였다. 클로닝된 xylanase 유전자는 xyn11B로 명명되었으며, 356 아미노산으로 구성된 단백질을 코드하는 1,071 뉴클레오티드로 이루어졌다. Xyn11B의 아미노산 배열을 분석한 결과 glycosyl hydrolase family 11에 속하는 xylanase와 상동성이 높은 활성영역과 탄수화물 결합영역을 포함하고 있는 다영역 효소로 확인되었다. SignalP4.1 server로부터 아미노 말단의 26개 잔기가 signal peptide로 예측되었다. DEAE-Sepharose와 Phenyl-Separose 컬럼 크로마토그래피 과정을 통해 xyn11B 유전자를 함유한 재조합 대장균의 균체 파쇄상등액으로부터 Xyn11B를 부분 정제하였다. 부분 정제된 Xyn11B의 반응특성을 조사한 결과 pH 6.5와 $50^{\circ}C$에서 최대 반응활성을 보였고 birchwood xylan이나 oat spelt xylan보다 arabinoxylan에 대한 활성이 높았으며 셀룰로스, 만난과 para-nitrophenyl-${\beta}$-xylopyranoside에 대해서는 분해활성이 없었다. Xyn11B의 활성은 $Ca^{2+}$과 $Mg^{2+}$에 의해서는 약간 증가한 반면에 $Cu^{2+}$, $Ni^{2+}$, $Fe^{3+}$, $Mn^{2+}$에 의해서는 크게 저해되었고 SDS에 의해서 완전히 저해되었다.

• Journal of Microbiology and Biotechnology
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• 제24권11호
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• pp.1525-1535
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• 2014

The xynC gene, which encodes high molecular weight xylanase from Paenibacillus sp. DG-22, was cloned and expressed in Escherichia coli, and its nucleotide sequence was determined. The xynC gene comprised a 4,419bp open reading frame encoding 1,472 amino acid residues, including a 27 amino acid signal sequence. Sequence analysis indicated that XynC is a multidomain enzyme composed of two family 4_9 carbohydrate-binding modules (CBMs), a catalytic domain of family 10 glycosyl hydrolases, a family 9 CBM, and three S-layer homologous domains. Recombinant XynC was purified to homogeneity by heat treatment, followed by Avicel affinity chromatography. SDS-PAGE and zymogram analysis of the purified enzyme identified three active truncated xylanase species. Protein sequencing of these truncated proteins showed that all had identical N-terminal sequences. In the protein characterization, recombinant XynC exhibited optimal activity at pH 6.5 and $65^{\circ}C$ and remained stable at neutral to alkaline pH (pH 6.0-10.0). The xylanase activity of recombinant XynC was strongly inhibited by 1 mM $Cu^{2+}$ and $Hg^{2+}$, whereas it was noticeably enhanced by 10 mM dithiothreitol. The enzyme exhibited strong activity towards xylans, including beechwood xylan and arabinoxylan, whereas it showed no cellulase activity. The hydrolyzed product patterns of birchwood xylan and xylooligosaccharides by thin-layer chromatography confirmed XynC as an endoxylanase.

• 한국미생물·생명공학회지
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• 제44권3호
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• pp.324-332
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• 2016

왕겨를 탄소원으로 사용하여 증균 배양을 실시함으로써 국내 사찰에서 제조된 된장으로부터 xylan 분해능 우수한 균주를 분리하였다. 분리균 YB-1301은 DNA gyrase subunit B 유전자(gyrB)의 염기서열에 근거하여 Bacillus safensis로 동정되었다. B. safensis YB-1301을 밀기울 또는 여러 종류의 xylan들이 첨가된 배지에서 배양하였을 때 xylanase의 생산성이 급격하게 증가되었다. 특히 birchwood xylan이 첨가된 LB 배지에서 플라스크 배양을 하였을 때 최대 340 U/ml 이상의 xylanase 생산성을 보였다. Xylan이 첨가되지 않은 LB 배지에서는 매우 소량의 xylanase가 균의 성장과 연계되어 항시적으로 생산되지만, xylan이 첨가된 배지에서는 정지기 생육단계에서 xylanase의 생산이 크게 유도되었다. 더구나 xylanase 생합성은 가수분해되지 않은 xylan 보다 xylan의 효소적 가수분해 산물에 의해 더 빠르게 유도되었다. 또한 B. safensis YB-1301의 배양상등액에 존재하는 xylanase는 55℃와 pH 6.5−7.0의 반응조건에서 최대활성을 나타냈다.

• 미생물학회지
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• 제36권3호
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• pp.196-202
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• 2000

Bacillus circulans ATCC21367의 Cellulolytic Xylanase 유전자를 pUC19을 vector 로 하여 대장균내에서 클로닝 하였다. 재조합 plasmid pXL180은 B. circulans 로부터 유래 된 0.5 kb와 1.3 kb Pst I 절편으로 이루어진 총 1.8 kb 삽입 절편을 포함 하고 있었다. 1.3 kb 절편의 상류영역에 있는 0.5 kb 절편은 클로닝된 유전자의 정상 발현뿐만아니라 과잉 발 현에 대해서도 필수 불가결함을 확인하였다. 형질전환체는 모균 B. circulans에 의해 생산된 것보다 135배 이상 많은 xylanase를 생산하였다. 클로닝된 효소의 최적 pH와 온도는 각각 pH 5.2와 $60^{\circ}C$ 였다. $55^{\circ}C$에서 1시간 동안의 사전 연처리에도 이 효소는 활성의 감소를 일 으키지 않았다. 이 효소는 xylan과 carboxymethyl cellulose (CMC), lichenan에 대하여 기질 특이성을 보였는데, 주요 산물로서 xylose(EH는 G1)와 xylobiose(또는 G2), xylotriose(또는 G3)를 생산하였다. 그러므로 우리는 클로닝된 유전자의 효소를 cellulolytic xylanase로 명명 하였다. 액체 배양된 Eschericxhia coli DH5$\alpha$(pXL180)의 전체 세포 추충물이나 배양 상등 액으로부터 조제된 시료들의 SDSPAGE와 zymogram을 통하여 이 효소의 분자량은 45kDa 이었으며, 대장균 내에서 주목할 만한 processing은 일어나지 않았다.

• Journal of Microbiology and Biotechnology
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• 제5권3호
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• pp.117-124
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• 1995

A gene (xynA) encoding the endo-xylanase (E.C.3.2.1.8) from Bacillus stearothermophilus was cloned in E. coli, and its complete nucleotide sequence was determined. The xynA gene consists of a 636 base pairs open reading frame coding for a protein of 212 amino acids with a deduced molecular weight of 23, 283 Da. A putative signal sequence of 27 amino acid residues shows the features comparable with the Bacillus signal sequences; namely, the signal contains a positively charged region close to the N-terminus followed by a long hydrophobic string. The coding sequence is preceded by a possible ribosome binding site with a free energy value of -16.6 kcal/mol and the transcription initiation signals are located further upstream. The translation termination codon (TAA) at the 3 end of the coding sequence is followed by two palindrome sequences, one of which is thought to act as a terminator. The xynA gene has a high GC content, especially in the wobble position of codons (64%). Comparison of the primary protein sequence with those of other xylanases shows a high homology to the xylanases belonging to family G.

• Journal of Microbiology and Biotechnology
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• 제18권3호
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• pp.410-416
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• 2008

The gene SfXyn10, which encodes a protease-resistant xylanase, was isolated using colony PCR screening from a genomic library of a feather-degrading bacterial strain Streptomyces fradiae var. k11. The full-length gene consists of 1,437bp and encodes 479 amino acids, which includes 41 residues of a putative signal peptide at its N terminus. The amino acid sequence shares the highest similarity (80%) to the endo-1,4-${\beta}$-xylanase from Streptomyces coelicolor A3, which belongs to the glycoside hydrolase family 10. The gene fragment encoding the mature xylanase was expressed in Escherichia coli BL21 (DE3). The recombinant protein was purified to homogeneity by acetone precipitation and anion-exchange chromatography, and subsequently characterized. The optimal pH and temperature for the purified recombinant enzyme were 7.8 and $60^{\circ}C$, respectively. The enzyme showed stability over a pH range of 4.0-10.0. The kinetic values on oat spelt xylan and birchwood xylan substrates were also determined. The enzyme activity was enhanced by $Fe^{2+}$ and strongly inhibited by $Hg^{2+}$ and SDS. The enzyme also showed resistance to neutral and alkaline proteases. Therefore, these characteristics suggest that SfXyn10 could be an important candidate for protease-resistant mechanistic research and has potential applications in the food industry, cotton scouring, and improving animal nutrition.