Sun Qing-Li, Wang Ling-Yan, Shan Jun-Jie, Jiang Rong, Guo Lian-Hong, Zhang Yang, Zhang Ren, Li Yuan
Institute of Medicinal Biotechnology, Tian Tan, 100050 Beijing, China.
Arch Microbiol. 2007 Oct;188(4):333-40. doi: 10.1007/s00203-007-0253-6. Epub 2007 May 22.
Streptomyces sp. 139 produces a novel exopolysaccharide (EPS) designated Ebosin which has antagonistic activity for IL-1R in vitro and remarkable anti-rheumatic arthritis activity in vivo. We previously identified a ste (Streptomyces eps) gene cluster consisting of 27 ORFs responsible for Ebosin biosynthesis. The gene product of ste15 shows high homology to known glycosyltransferases (GTFs). To elucidate its function in Ebosin biosynthesis, the ste15 gene was knocked out with a double crossover via homologous recombination. Our analysis of monosaccharide composition for EPS-m produced by the mutant strain Streptomyces sp. 139 (ste15(-)) showed that glucose was significantly diminished compared to its natural counterpart Ebosin. This derivative of Ebosin lost the antagonistic activity for IL-1R in vitro and its molecular mass was smaller than Ebosin. These results have demonstrated that the ste15 gene codes for a GTF for glucose, which is functionally involved in Ebosin biosynthesis.
链霉菌属139产生一种新型胞外多糖（EPS），命名为埃博辛，它在体外对白细胞介素-1受体（IL-1R）具有拮抗活性，在体内具有显著的抗风湿性关节炎活性。我们之前鉴定出一个由27个开放阅读框（ORF）组成的ste（链霉菌胞外多糖）基因簇，该基因簇负责埃博辛的生物合成。ste15的基因产物与已知的糖基转移酶（GTF）具有高度同源性。为了阐明其在埃博辛生物合成中的功能，通过同源重组利用双交换敲除了ste15基因。我们对突变菌株链霉菌属139（ste15(-)）产生的EPS-m的单糖组成分析表明，与天然的埃博辛相比，葡萄糖显著减少。这种埃博辛衍生物在体外失去了对IL-1R的拮抗活性，并且其分子量小于埃博辛。这些结果表明，ste15基因编码一种葡萄糖糖基转移酶，在功能上参与埃博辛的生物合成。
