title: Gene cluster responsible for validamycin biosynthesis in Streptomyces hygroscopicus subsp. jinggangensis 5008.
abstract: A gene cluster responsible for the biosynthesis of validamycin, an aminocyclitol antibiotic widely used as a control agent for sheath blight disease of rice plants, was identified from Streptomyces hygroscopicus subsp. jinggangensis 5008 using heterologous probe acbC, a gene involved in the cyclization of D-sedoheptulose 7-phosphate to 2-epi-5-epi-valiolone of the acarbose biosynthetic gene cluster originated from Actinoplanes sp. strain SE50/110. Deletion of a 30-kb DNA fragment from this cluster in the chromosome resulted in loss of validamycin production, confirming a direct involvement of the gene cluster in the biosynthesis of this important plant protectant. A sequenced 6-kb fragment contained valA (an acbC homologue encoding a putative cyclase) as well as two additional complete open reading frames (valB and valC, encoding a putative adenyltransferase and a kinase, respectively), which are organized as an operon. The function of ValA was genetically demonstrated to be essential for validamycin production and biochemically shown to be responsible specifically for the cyclization of D-sedoheptulose 7-phosphate to 2-epi-5-epi-valiolone in vitro using the ValA protein heterologously overexpressed in E. coli. The information obtained should pave the way for further detailed analysis of the complete biosynthetic pathway, which would lead to a complete understanding of validamycin biosynthesis.
authors.affiliation: Bio-X Life Science Research Center, Shanghai Jiaotong University, Shanghai 200030, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Yu
authors.forename: Linquan
authors.initials: L
authors.lastname: Bai
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Minagawa
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Jian
authors.forename: Lei
authors.initials: L
authors.lastname: Li
authors.forename: Jialiang
authors.initials: J
authors.lastname: Li
authors.forename: Shuangya
authors.initials: S
authors.lastname: Chen
authors.forename: Erhu
authors.initials: E
authors.lastname: Cao
authors.forename: Taifo
authors.initials: T
authors.lastname: Mahmud
authors.forename: Heinz G
authors.initials: HG
authors.lastname: Floss
authors.forename: Xiufen
authors.initials: X
authors.lastname: Zhou
authors.forename: Zixin
authors.initials: Z
authors.lastname: Deng
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005658:Fungi / Q000187:drug effects / Q000254:growth & development; D015964:Gene Expression Regulation, Bacterial; D007294:Inositol / Q000031:analogs & derivatives / Q000096:biosynthesis / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D005810:Multigene Family; D012275:Oryza / Q000382:microbiology; D010935:Plant Diseases / Q000382:microbiology; D017422:Sequence Analysis, DNA; D013302:Streptomyces / Q000145:classification / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; C030790:validamycin A; D007294:Inositol