Journal of Microbiology

Research Support, Non-U.S. Gov't

Identification of a Methyltransferase Encoded by Gene ste16 and Its Function in Ebosin Biosynthesis of Streptomyces sp. 139: Hong-Guan Xie , Yong-Gang Bao , Li-ping Bai , Jun-Jie Shan , Rong Jiang , Yang Zhang , Lian-Hong Guo , Ren Zhang , Yuan Li; J. Microbiol. 2009;47(2):193-200. Published online May 2, 2009; DOI: https://doi.org/10.1007/s12275-008-0195-y

Abstract: Streptomyces sp. 139 generates a novel exopolysaccharide (EPS) designated as Ebosin, which exerts an antagonistic effect on IL-1R in vitro and anti-rheumatic arthritis activity in vivo. A ste gene cluster for Ebosin biosynthesis consisting of 27 ORFs was previously identified in our laboratory. In this paper, ste16 was expressed in Escherichia coli BL21 and the recombinant protein was purified, which has the ability to catalyze the transfer of the methyl group from S-adenosylmethionine (AdoMet) to dTDP-4-keto-6-deoxy-D-glucos, which was thus identified as a methyltransferase. In order to determine the function of ste16 in Ebosin biosynthesis, the gene was disrupted with a double crossover via homologous recombination. The monosaccharide composition of EPS-m generated by the mutant strain Streptomyces sp. 139 (ste16-) was found to differ from that of Ebosin. The IL-1R antagonist activity of EPS-m was markedly lower than that of Ebosin. These experimental results have shown that the ste16 gene codes for a methyltransferase which is involved in Ebosin biosynthesis.

Molecular Cloning and Analysis of Sporulation-Specific Glucoamylase (SGA) Gene of Saccharomyces diastaticus: Kang, Dae Ook , Hwang, In Kyu , Oh, Won Keun , Lee, Hyun Sun , Ahn, Cheol Soon , Kim, Bo Yeon , Mheen, Tae Ick , Ahn, Hong Seog; J. Microbiol. 1999;37(1):35-40.

Abstract: Sporulation-specific glucoamylase (SGA) gene was isolated from genomic library of Saccharomyces diastaticus 5114-9A by using glucoamylase non-producing mutant of S. diastaticus as a recipient. When the glucoamylase activities of culture supernatant, periplasmic, and intracellular fraction of cells transformed with hybrid plasmid containing SGA gene were measured, the highest activity was detected in culture supernatant. SGA produced by transformant and extracellular glucoamylase produced by S. diastaticus 5114-9A differed in enzyme characteristics such as optimum temperature, thermostability, and resistance to SDS and urea. But the characteristics of SGA produced by sporulating yeast cells and vegetatively growing transformants were identical.

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