title: Identification of alpha-D-glucose-1-phosphate cytidylyltransferase involved in Ebosin biosynthesis of Streptomyces sp. 139.
abstract: Ebosin, a novel exopolysaccharide produced by Streptomyces sp. 139 has antagonist activity for IL-1R in vitro and remarkable anti-rheumatic arthritis activity in vivo. Its biosynthesis gene cluster (ste) has been identified. In this study, gene ste17 was expressed in Escherichia coli BL21 and the recombinant protein was purified. With CTP and alpha-D-glucose-1-phosphate as substrates, the recombinant Ste17 protein was found capable of catalyzing the production of CDP-D-glucose and pyrophosphate, demonstrating its identity as an alpha-D-glucose-1-phosphate-cytidylyltransferase (CDP-D-glucose synthase). To investigate the function of ste17 in Ebosin biosynthesis, the gene was disrupted with a double crossover via homologous recombination. The monosaccharide composition of exopolysaccharide (EPS) produced by the mutant Streptomyces sp. 139 (ste17 (-)) was found significantly altered from that of Ebosin, with glucose becoming undetectable. This gene knockout also negatively affected the antagonist activity for IL-1R of EPS. These results indicate that the CDP-D: -glucose synthase encoded by ste17 gene is involved in the formation of nucleotide sugar (CDP-D-glucose) as glucose precursor in Ebosin biosynthesis.
authors.affiliation: Key Laboratory of Biotechnology of Antibiotics, Ministry of Health, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Tian Tan, 100050, Beijing, China.
authors.forename: Xiao-Qiang
authors.initials: XQ
authors.lastname: Qi
authors.forename: Qing-Li
authors.initials: QL
authors.lastname: Sun
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Bai
authors.forename: Jun-Jie
authors.initials: JJ
authors.lastname: Shan
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Ren
authors.initials: R
authors.lastname: Zhang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li