Search | Korea Science

Deng, Aihua;Zhang, Guoqiang;Shi, Nana;Wu, Jie;Lu, Fuping;Wen, Tingyi
- Journal of Microbiology and Biotechnology
- /
- v.24 no.2
- /
- pp.197-208
- /
- 2014
A novel protease gene from Bacillus gibsonii, aprBG, was cloned, expressed in B. subtilis, and characterized. High-level expression of aprBG was achieved in the recombinant strain when a junction was present between the promoter and the target gene. The purified recombinant enzyme exhibited similar N-terminal sequences and catalytic properties to the native enzyme, including high affinity and hydrolytic efficiency toward various substrates and a superior performance when exposed to various metal ions, surfactants, oxidants, and commercial detergents. AprBG was remarkably stable in 50% organic solvents and retained 100% activity and stability in 0-4 M NaCl, which is better than the characteristics of previously reported proteases. AprBG was most closely related to the high-alkaline proteases of the subtilisin family with a 57-68% identity. The secretion and maturation mechanism of AprBG was dependent on the enzyme activity, as analyzed by site-directed mutagenesis. Thus, when taken together, the results revealed that the halo-solvent-tolerant protease AprBG displays significant activity and stability under various extreme conditions, indicating its potential for use in many biotechnology applications.
https://doi.org/10.4014/jmb.1308.08094 인용 PDF KSCI KPUBS HTML

Yao, Zhuang;Meng, Yu;Le, Huong Giang;Kim, Jeong A;Kim, Jeong Hwan
- Microbiology and Biotechnology Letters
- /
- v.47 no.4
- /
- pp.522-529
- /
- 2019
A Bacillus strain, SJ4, exhibiting strong fibrinolytic activity was isolated from saeu (shrimp, Acetes chinensis) jeotgal, a Korean traditional fermented food and was identified as B. subtilis. The B. subtilis SJ4 strain can grow at a NaCl concentration of up to 15% (w/v). The fibrinolytic activity of B. subtilis SJ4 (152.0 U/ml) cultured in Luria-Bertani (LB) broth for 48 h at 37℃ with aeration was higher than that of B. subtilis SJ4 cultured in TSB (124.5 U/ml) under same culture conditions. The major proteins in the LB culture supernatant of B. subtilis SJ4 were analyzed by SDS-PAGE, which revealed three major bands (23, 25, and 28 kDa). The band (23 kDa) with strong fibrinolytic activity, analyzed on fibrin zymogram, was observed at 60-96 h of cultivation. The aprESJ4 gene encoding the major fibrinolytic enzyme, AprESJ4, was cloned by PCR. The aprESJ4 gene sequence exhibited high similarities with the fibrinolytic gene sequences of other Bacillus species. The amino acid sequence of AprESJ4 exhibited 98.9 and 98.4% similarity with subtilisin NAT and AprE2 of B. subtilis, respectively. Hence, B. subtilis SJ4 can be a potential starter culture for jeotgal products.
https://doi.org/10.4014/mbl.1906.06003 인용 PDF KSCI

Kim, Gyoung-Min;Lee, Ae-Ran;Lee, Kang-Wook;Park, Ae-Yong;Chun, Ji-Yeon;Cha, Jae-Ho;Song, Young-Sun;Kim, Jeong-Hwan
- Journal of Microbiology and Biotechnology
- /
- v.19 no.9
- /
- pp.997-1004
- /
- 2009
Bacillus amyloliquefancies CH51 isolated from cheonggukjang, a traditional Korean fermented soy food, has strong fibrinolytic activity and produces several fibrinolytic enzymes. Among four different growth media, tryptic soy broth was the best in terms of supporting cell growth and fibrinolytic activity of this strain. A protein with fibrinolytic activity was partially purified from the culture supernatant by CM-Sephadex and Phenyl Sepharose column chromatographies. Tandem mass spectrometric analysis showed that this protein is a homolog of AprE from B. subtilis and it was accordingly named AprE51. The optimum pH and temperature for partially purified AprE51 activity were 6.0 and $45^{\circ}C$, respectively. A gene encoding AprE51, aprE51, was cloned from B. amyloliquefaciens CH51 genomic DNA. The aprE51 gene was overexpressed in heterologous B. subtilis strains deficient in fibrinolytic activity using an E. coli-Bacillus shuttle vector, pHY300PLK.
PDF KSCI