title: Disruption of ste23 gene affects composition profile and bioactivity of exopolysaccharide produced by Streptomyces sp. 139.
abstract: OBJECTIVE
  To study the function of the gene ste23 involved in the biosynthesis of Ebosin.
  
  
  RESULTS
  In search of databases, the deduced product of the gene ste23 showed high homology to dTDP-4-dehydrorhamnose 3,5-epimerases. ste23 was replaced by a kanamycin resistance gene through double crossover. Compared with Ebosin, an exopolysaccharide (EPS) produced by wild-type Streptomyces sp. 139, the EPS produced by the ste23 mutant (designated EPS1) had a remarkably different monosaccharide composition and significantly diminished rhamnose content, though the molecular mass of EPS1 was similar to that of Ebosin. In addition, EPS1 lost the interleukin 1 (IL-1) antagonist activity in vitro.
  
  
  CONCLUSIONS
  ste23 may be involved in the Ebosin biosynthesis in S. sp. 139. and its bioactivity.
  
  
  CONCLUSIONS
  This is the first genetic work investigating functions of genes involved in EPS production in streptomyces by gene replacement of the pathway genes.
authors.affiliation: Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: T
authors.initials: T
authors.lastname: Zhang
authors.forename: L
authors.initials: L
authors.lastname: Wang
authors.forename: G
authors.initials: G
authors.lastname: Xu
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.forename: Y
authors.initials: Y
authors.lastname: Li
mesh_terms: D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D020868:Gene Silencing; D005816:Genetic Complementation Test; D008666:Metalloendopeptidases / Q000235:genetics* / Q000502:physiology; D009005:Monosaccharides / Q000032:analysis; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics / Q000494:pharmacology; D017472:Receptors, Interleukin-1 / Q000037:antagonists & inhibitors; D013302:Streptomyces / Q000235:genetics* / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D009005:Monosaccharides; D011135:Polysaccharides, Bacterial; D017472:Receptors, Interleukin-1; C098632:exopolysaccharide, Streptococcus; D008666:Metalloendopeptidases