• Journal of Microbiology and Biotechnology
• /
• 제19권10호
• /
• pp.1169-1175
• /
• 2009

An antifungal chitinase, ChiCW, produced by Bacillus cereus 28-9 is effective against conidial germination of Botrytis elliptica, the causal agent of lily leaf blight. ChiCW as a modular enzyme consists of a signal peptide, a catalytic domain, a fibronectin type-III-like domain, and a chitin-binding domain. When two C-terminal domains of ChiCW were truncated, $ChiCW{\Delta}FC$ (lacking the chitin-binding domain and fibronectin type III-like domain) lost its antifungal activity. Since $ChiCW{\Delta}C$ (lacking the chitin-binding domain) could not be expressed in Escherichia coli as $ChiCW{\Delta}FC$ did, a different strategy based on protein engineering technology was designed to investigate the involvement of the chitin-binding domain of ChiCW ($ChBD_{ChiCW}$) in antifungal activity in this study. Because ChiA1 of Bacillus circulans WL-12 is a modular enzyme with a higher hydrolytic activity than ChiCW but not inhibitory to conidial germination of Bo. elliptica and the similar domain composition of ChiA1 and ChiCW, the C-terminal truncated derivatives of ChiA1 were generated and used to construct chimeric chitinases with $ChBD_{ChiCW}$. When the chitin-binding domain of ChiA1 was replaced with $ChBD_{ChiCW}$, the chimeric chitinase named ChiAAAW exhibited both high enzyme activity and antifungal activity. The results indicate that $ChBD_{ChiCW}$ may play an important role in the antifungal activity of ChiCW.

• 한국식물병리학회:학술대회논문집
• /
• 한국식물병리학회 2002년도 총회 및 추계학술발표회
• /
• pp.57.1-57
• /
• 2002

• BMB Reports
• /
• 제44권6호
• /
• pp.375-380
• /
• 2011

Bacillus licheniformis SK-1 naturally produces chitinase 72 (CHI72) with two truncation derivatives at the C-terminus, one with deletion of the chitin binding domain (ChBD), and the other with deletions of both fibronectin type III domain (FnIIID) and ChBD. We constructed deletions mutants of CHI72 with deletion of ChBD (CHI72${\Delta}$ChBD) and deletions of both FnIIID and ChBD (CHI72${\Delta}$FnIIID${\Delta}$ChBD), and studied their activity on soluble, amorphous and crystalline substrates. Interestingly, when equivalent amount of specific activity of each enzyme on soluble substrate was used, the product yield from CHI72-${\Delta}$ChBD and CHI72${\Delta}$FnIIID${\Delta}$ChBD on colloidal chitin was 2.5 and 1.6 fold higher than CHI72, respectively. In contrast, the product yield from CHI72${\Delta}$ChBD and CHI72${\Delta}$FnIIID-${\Delta}$ChBD on ${\beta}$-chitin reduced to 0.7 and 0.5 fold of CHI72, respectively. These results suggest that CHI72 can modulate its substrate specificities through truncations of the functional domains at the C-terminus, producing a mixture of enzymes with elevated efficiency of hydrolysis.

• Journal of Microbiology and Biotechnology
• /
• 제16권12호
• /
• pp.1897-1903
• /
• 2006

In order to investigate the functions of the C-terminal region of chitinase ChiCW of Bacillus cereus 28-9, a C-terminal truncated enzyme, ChiCW$\Delta$FC, was expressed in Escherichia coli and purified to homogeneity for biochemical characterization. Compared with ChiCW, ChiCW$\Delta$FC exhibited higher chitinase activity at high temperature and pH, but expressed lower hydrolytic and binding activities toward insoluble substrates. In addition, kinetic properties indicated that ChiCW$\Delta$MC hydrolyzed oligomeric and polymeric substrates less efficiently than ChiCW. These results suggest that the C-terminal region of ChiCW plays important roles in substrate binding and hydrolysis of chitin. In addition, the biological meaning of C-terminal proteolytic modification of ChiCW is discussed.

• 산업기술연구
• /
• 제36권
• /
• pp.33-37
• /
• 2016

Cellulose binding domains (CBDs) of cellulases are thought to assist in the hydrolysis of insoluble crystalline cellulose. To gain sufficient amount of CBDs, the self-cleavable intein tag was used for expression and purification of Trichoderma reesei cellobiohydrolase I CBD in E. coli. Synthetic CBD genes, CBD or linker-CBD were cloned into expression vector pTYB11. Recombinant CBDs were successfully purified by intein mediated purification with an affinity chitin-binding domain. The final yields of recombinant CBD and linker-CBD were 3.2 mg/L and 1.4 mg/L, respectively. The functional bindings of recombinant CBDs were confirmed by Avicel binding experiments. The simple and easy purification method using self-cleavable intein tag can be further used in pretreatment of crystalline cellulose or characterization of engineered CBDs.

• 한국미생물학회:학술대회논문집
• /
• 한국미생물학회 2006년도 International Meeting of the Microbiological Society of Korea
• /
• pp.97-99
• /
• 2006

A chitinase-producing bacterium strain KCTC10714 was isolated from sea sand around the King Sejong Station, King George Island in Antarctica. It was identified as Sanguibacter sp., based on the biochemical properties and 16S rRNA gene sequence. KCTC10714 chitinase showed enzyme activity in broad range of temperature from 0 to $70^{\circ}C$. At $0^{\circ}C$, it showed 70.9% of relative activity in comparison with 100%. The chitinase gene of KCTC10714 was cloned using inverse PCR cloning method. KCTC10714 chitinase gene was designated as chi21702. The ORF of chi21702 consisted of 1,449 bp (482 amino acid), and contained ChtBD3 (a chitin/cellulose binding domain) and an active site for chitinase family 18.

• 생명과학회지
• /
• 제32권2호
• /
• pp.135-141
• /
• 2022

Mouse thymosin β-4 (TB4) 유전자를 Escherichia coli에서 intein-tag 융합 단백질로 발현시키고 정제하였다. 재조합 TB4-intein 융합 단백질의 분자량을 10% glycine SDS-PAGE로 확인한 결과, 세포내 soluble 분획에서 60 kDa의 단백질을 얻을 수 있었고, 유도발현 최적 조건은 0.1 mM IPTG, 25℃에서 3시간 동안 유도 발현할 때가 최적임을 확인하였다. TB4 만을 얻기 위해서 유도발현된 TB4-intein을 DTT를 이용해 self-cleavage를 일으킨 다음, chitin bead를 이용한 친화성 크로마토그라피로 정제 후 분자량을 확인 한 결과, 5 kDa으로 확인되었으며, 순도는 95%이상 이었다. 정제한 recombinant TB4가 생물학적 기능을 보유하고 있는지 확인을 하기 위하여, TB4를 농도 별(1~1,000 ng/ml)로 하여 HT1080 cell을 이용한 cell migration을 측정한 결과, 모든 농도에서 recombinant TB4가 화학합성한 TB4 보다 약 20% 이상 높은 활성을 보였으며, recombinant TB4 1 ng/ml의 농도에서 cell migration 활성이 가장 높게 나타났다. Recombinant TB4를 마우스 상처 부위에 5일 동안 매일 처리한 결과(최종 처리 농도 0.5 mg/ml), 화학합성 TB4 보다 recombinant TB4의 상처치유 활성이 약 35% 더 높음을 알 수 있었다. 이상의 결과는 recombinant TB4가 화학합성 TB4보다 cell migration과 상처치유에 훨씬 높은 활성을 나타냄을 보여주고 있다.

• Journal of Microbiology and Biotechnology
• /
• 제19권3호
• /
• pp.277-285
• /
• 2009

The nucleotide sequence of the Paenibacillus curdlanolyticus B-6 xyn10A gene, encoding a xylanase Xyn10A, consists of 3,828 nucleotides encoding a protein of 1,276 amino acids with a predicted molecular mass of 142,726 Da. Sequence analysis indicated that Xyn10A is a multidomain enzyme comprising nine domains in the following order: three family 22 carbohydrate-binding modules (CBMs), a family 10 catalytic domain of glycosyl hydrolases (xylanase), a family 9 CBM, a glycine-rich region, and three surface layer homology (SLH) domains. Xyn10A was purified from a recombinant Escherichia coli by a single step of affinity purification on cellulose. It could effectively hydrolyze agricultural wastes and pure insoluble xylans, especially low substituted insoluble xylan. The hydrolysis products were a series of short-chain xylooligosaccharides, indicating that the purified enzyme was an endo-$\beta$-1,4-xylanase. Xyn10A bound to various insoluble polysaccharides including Avicel, $\alpha$-cellulose, insoluble birchwood and oat spelt xylans, chitin, and starches, and the cell wall fragments of P. curdlanolyticus B-6, indicating that both the CBM and the SLH domains are fully functioning in the Xyn10A. Removal of the CBMs from Xyn10A strongly reduced the ability of plant cell wall hydrolysis. These results suggested that the CBMs of Xyn10A play an important role in the hydrolysis of plant cell walls.

• The Plant Pathology Journal
• /
• 제33권3호
• /
• pp.318-328
• /
• 2017

Chitinase-producing Paenibacillus elgii strain HOA73 has been used to control plant diseases. However, the antimicrobial activity of its extracellular chitinase has not been fully elucidated. The major extracellular chitinase gene (PeChi68) from strain HOA73 was cloned and expressed in Escherichia coli in this study. This gene had an open reading frame of 2,028 bp, encoding a protein of 675 amino acid residues containing a secretion signal peptide, a chitin-binding domain, two fibronectin type III domains, and a catalytic hydrolase domain. The chitinase (PeChi68) purified from recombinant E. coli exhibited a molecular mass of approximately 68 kDa on SDS-PAGE. Biochemical analysis indicated that optimum temperature for the actitvity of purified chitinase was $50^{\circ}C$. However, it was inactivated with time when it was incubated at $40^{\circ}C$ and $50^{\circ}C$. Its optimum activity was found at pH 7, although its activity was stable when incubated between pH 3 and pH 11. Heavy metals inhibited this chitinase. This purified chitinase completely inhibited spore germination of two Cladosporium isolates and partially inhibited germination of Botrytis cinerea spores. However, it had no effect on the spores of a Colletotricum isolate. These results indicate that the extracellular chitinase produced by P. elgii HOA73 might have function in limiting spore germination of certain fungal pathogens.

• 유기물자원화
• /
• 제18권3호
• /
• pp.31-37
• /
• 2010

Chitinase (EC 3.2.1.14)는 곰팡이와 곤충 등에서 세포벽이나 외골격을 형성하는 생물학적 방어기질의 구성 요소인 chitin의 ${\beta}$-1,4-linkages를 가수분해하는 효소이다. 이러한 chitinase를 포함하는 Glycosyl hydrolases 18 family는 Archea, Prokaryotes 그리고 Eukaryotes에 널리 퍼져 있는 Ancient gene으로 알려져 있다. 그 중, 지렁이는 곰팡이와 세균이 많은 환경에서 자라기 때문에 이러한 미생물들의 공격으로부터 스스로를 보호할 수 있는 면역체계를 가지고 있는 것으로 알려져 왔다. 본 연구에서는, 붉은줄지렁이 (Eisenia andrei)의 중장에서 발현되는 Chitinases의 cDNA 서열을 얻기 위해 기존에 알려져 있던 EST 서열을 가지고 RT-PCR 및 RACE-PCR을 수행하였고 이를 통해 E. andrei의 중장에서 발현되는 Chitinase의 특성을 동정 및 규명하였다. 그 결과 309개의 아미노산을 암호화하는 927개의 염기 서열을 얻을 수 있었으며 다른 종들의 Chitinases와 아미노산 서열을 비교 분석한 결과 지렁이의 Chitinase는 Glycosyl hydrolases 18 family에 속하고, 기질 결합과 촉매 작용에 관여하는 2개의 영역이 잘 보존되어 있는 것으로 나타났다.