title: Identification and functional analysis of the chain length determinant gene ste8 involved in the biosynthesis of ebosin by Streptomyces sp. 139.
abstract: Ebosin, a novel exopolysaccharide produced by Streptomyces sp. 139, has obvious antirheumatic arthritis activity in vivo, and its biosynthesis gene cluster (ste), consisting of 27 open reading frames, has been identified. This paper reports our study of the gene functionality of ste8, the predicted protein product of which is homologous to some bacterial chain length determinant Wzz proteins. For characterization of Ste8, ste8 was cloned and expressed in the mutant strain E. coli 086:H2 (Δwzz). The functional complementation of wzz by ste8 was demonstrated by the restoration of wild-type lipopolysaccharide biosynthesis and increased levels of serum resistance of E. coli 086:H2 (Δwzz) (pET30a-ste8). To examine the function of ste8 in ebosin biosynthesis, the gene was knocked out with a double crossover via homologous recombination. The molecular weight of the ebosin derivative EPS-8m produced by the mutant Streptomyces sp. 139 (ste8(-)) was much lower than that of ebosin, and the binding activity of EPS-8m for IL-1R decreased significantly compared with ebosin. These results demonstrate that ste8 encodes a chain length determinant (Wzz) that functions 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, Beijing 100050, China.
authors.forename: Zhang
authors.initials: Z
authors.lastname: Yang
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Li
authors.forename: Xiaoqaing
authors.initials: X
authors.lastname: Qi
authors.forename: Junjie
authors.initials: J
authors.lastname: Shan
authors.forename: Rong
authors.initials: R
authors.lastname: Jiang
authors.forename: Lianhong
authors.initials: L
authors.lastname: Guo
authors.forename: Ren
authors.initials: R
authors.lastname: Zhang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D053898:Biosynthetic Pathways / Q000235:genetics; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D017353:Gene Deletion; D005816:Genetic Complementation Test; D005810:Multigene Family; D011135:Polysaccharides, Bacterial / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013302:Streptomyces / Q000235:genetics* / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D011135:Polysaccharides, Bacterial; C075969:rol protein, Bacteria