title: [Characterization of the spore-pigment biosynthetic gene cluster (sah) in Streptomyces sahachiroi ATCC 33158].
abstract: OBJECTIVE
  A putative type II polyketide synthase (PKS) gene cluster (sah) was found in the genome sequence of Streptomyces sahachiroi ATCC 33158 by bioinformatics. In order to discover its biological function, we cloned the sah cluster and made functional analyses by gene knockout and heterologous expression.
  
  
  RESULTS
  Annotation of the predicted open reading frames (ORFs) by protein-protein blast revealed that the sah cluster is highly homologous with the spore-pigment biosynthetic cluster (whiE) in S. coelicolor A3 (2), except an additional O-methyltransferase gene (sahI). Three genes of the sah cluster, sahG, sahH and sahI, which are putatively involved in post-PKS modifications, were respectively in-frame deleted by double crossover. We observed the color of the mutant strains spores apparently changed. HPLC and LC-MS analyses demonstrated that heterologous expression of the sah-minimal PKS gene and the whiE-minimal PKS gene in S. lividans ZX1 produced the same hydrophilic red pigments.
  
  
  CONCLUSIONS
  The sah cluster is responsible for the spore-pigment biosynthesis of S. sahachiroi ATCC 33158. It catalyzes the formation of polyketides with the same core structures as that of the whiE cluster.
authors.affiliation: State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China. lh861218@163.com
authors.forename: Hua
authors.initials: H
authors.lastname: Li
authors.forename: Lijuan
authors.initials: L
authors.lastname: Wang
authors.forename: Jing
authors.initials: J
authors.lastname: He
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D005810:Multigene Family; D016366:Open Reading Frames; D010860:Pigments, Biological / Q000096:biosynthesis*; D013171:Spores, Bacterial / Q000235:genetics / Q000378:metabolism*; D013302:Streptomyces / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D010860:Pigments, Biological