title: Characterization of an Ebosin derivative produced by heterologous gene replacement in Streptomyces sp. 139.
abstract: BACKGROUND
  Ebosin is a novel exopolysaccharide (EPS) produced by Streptomyces sp. 139 and evidenced to possess an anti-rheumatic arthritis activity in vivo. The Ebosin biosynthesis gene cluster (ste) consists of 27 ORFs and ste7 has previously been demonstrated to code for a fucosyltransferase, which plays an essential role in the formation of repeating sugar units during Ebosin production. Aiming to generate derivatives of Ebosin for better activity, we replaced ste7 with a gene encoding for a glucosyltransferase (gtf) from Streptococcus thermophilus.
  
  
  RESULTS
  This alteration resulted in a novel Ebosin derivative (EPS-7 g) with its monosaccharide composition dramatically changed, especially in the proportion of glucose which increased from 1.1% (Ebosin) to 84.01% (EPS-7 g). In an ELISA analysis, EPS-7 g exhibited a higher binding activity for IL-1R, as a competitor of interleukin-1, than that of Ebosin. It also exhibited a higher inhibitory effect on the activity of IL-1β-converting enzyme and production of IL-1β in fibroblast-like synoviocytes (FLS). In addition, experiments with acute inflamed mice induced by croton oil showed a significantly higher anti-inflammatory activity of EPS-7 g compared with Ebosin.
  
  
  CONCLUSIONS
  The new Ebosin derivative EPS-7 g is more bioactive than Ebosin evaluated by a series of experiments. This is the first report demonstrating a modification of EPS structure via heterologous gene replacement in Streptomyces.
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. e-zhangyang@163.com.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Institute of Pharmacology and Toxicology, Taiping Road, 100850, Beijing, China. shanjunjie001@126.com.
authors.forename: Junjie
authors.initials: J
authors.lastname: Shan
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. bao_yonggang@163.com.
authors.forename: Yonggang
authors.initials: Y
authors.lastname: Bao
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. lipingbai1973@163.com.
authors.forename: Liping
authors.initials: L
authors.lastname: Bai
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. jr5602@163.com.
authors.forename: Rong
authors.initials: R
authors.lastname: Jiang
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. guolh5@sina.com.
authors.forename: Lianhong
authors.initials: L
authors.lastname: Guo
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. yaochen3320@sina.com.
authors.forename: Chen
authors.initials: C
authors.lastname: Yao
authors.affiliation: School of Biological Sciences, University of Wollongong, Wollongong, NSW, 2522, Australia. rzhang@uow.edu.au.
authors.forename: Ren
authors.initials: R
authors.lastname: Zhang
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. yuanwli@263.net.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000378:metabolism / Q000494:pharmacology; D005798:Genes, Bacterial; D053583:Interleukin-1beta / Q000378:metabolism; D051379:Mice; D005810:Multigene Family; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D017472:Receptors, Interleukin-1 / Q000378:metabolism; D048249:Streptococcus thermophilus / Q000235:genetics*; D013302:Streptomyces / Q000235:genetics / Q000378:metabolism
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; C587672:IL1B protein, mouse; C000594089:IL1B protein, rat; D053583:Interleukin-1beta; D011135:Polysaccharides, Bacterial; D017472:Receptors, Interleukin-1