Title Identification of the Genes Involved in 1-Deoxynojirimycin Synthesis in Bacillus subtilis MORI 3K-85
Author Kyung-Don Kang1, Yong Seok Cho1,2, Ji Hye Song3,4, Young Shik Park1, Jae Yeon Lee1, Kyo Yeol Hwang1, Sang Ki Rhee4, Ji Hyung Chung5, Ohsuk Kwon3,6*, and Su-Il Seong1,2*
Address 1R&D center for Life Science, Biotopia Co., Ltd. Chuncheon, Gangwon-do 200-881, Republic of Korea, 2Department of Life Science, The University of Suwon, Gyeonggi-do 445-743, Republic of Korea, 3Integrative Omics Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Republic of Korea, 4Department of Medicinal Biotechnology, Soonchunhyang University, Chungnam 336-745, Republic of Korea, 5Cardiovascular Research Institute, Yonsei University College of Medicine, Seoul 120-749, Republic of Korea, 6Systems Biotechnology Program, School of Science, University of Science and Technology, Daejeon 305-350, Republic of Korea
Bibliography Journal of Microbiology, 49(3),431-440, 2011,
Key Words Bacillus subtilis MORI 3K-85, genomic DNA library screening, 1-deoxynojirimycin (DNJ), α-glucosidase inhibitor, gene cloning
Abstract 1-Deoxynojirimycin (DNJ), a D-glucose analogue with a nitrogen atom substituting for the ring oxygen, is a strong inhibitor of intestinal α-glucosidase. DNJ has several promising biological activities, including its antidiabetic, antitumor, and antiviral activities. Nevertheless, only limited amounts of DNJ are available because it can only be extracted from some higher plants, including the mulberry tree, or purified from the culture broth of several types of soil bacteria, such as Streptomyces sp. and Bacillus sp. In our previous study, a DNJ-producing bacterium, Bacillus subtilis MORI, was isolated from the traditional Korean fermented food Chungkookjang. In the present study, we report the identification of the DNJ biosynthetic genes in B. subtilis MORI 3K-85 strain, a DNJ-overproducing derivate of the B. subtilis MORI strain generated by γ-irradiation. The genomic DNA library of B. subtilis MORI 3K-85 was constructed in Escherichia coli, and clones showing α-glucosidase inhibition activity were selected. After DNA sequencing and a series of subcloning, we were able to identify a putative operon which consists of gabT1, yktc1, and gutB1 genes predicted to encode putative transaminase, phosphatase, and oxidoreductase, respectively. When a recombinant plasmid containing this operon sequence was transformed into an E. coli strain, the resulting transformant was able to produce DNJ into the culture medium. Our results indicate that the gabT1, yktc1, and gutB1 genes are involved in the DNJ biosynthetic pathway in B. subtilis MORI, suggesting the possibility of employing these genes to establish a large-scale microbial DNJ overproduction system through genetic engineering and process optimization.