title: Identification and characterization of a new erythromycin biosynthetic gene cluster in Actinopolyspora erythraea YIM90600, a novel erythronolide-producing halophilic actinomycete isolated from salt field.
abstract: Erythromycins (Ers) are clinically potent macrolide antibiotics in treating pathogenic bacterial infections. Microorganisms capable of producing Ers, represented by Saccharopolyspora erythraea, are mainly soil-dwelling actinomycetes. So far, Actinopolyspora erythraea YIM90600, a halophilic actinomycete isolated from Baicheng salt field, is the only known Er-producing extremophile. In this study, we have reported the draft genome sequence of Ac. erythraea YIM90600, genome mining of which has revealed a new Er biosynthetic gene cluster encoding several novel Er metabolites. This Er gene cluster shares high identity and similarity with the one of Sa. erythraea NRRL2338, except for two absent genes, eryBI and eryG. By correlating genotype and chemotype, the biosynthetic pathways of 3'-demethyl-erythromycin C, erythronolide H (EH) and erythronolide I have been proposed. The formation of EH is supposed to be sequentially biosynthesized via C-6/C-18 epoxidation and C-14 hydroxylation from 6-deoxyerythronolide B. Although an in vitro enzymatic activity assay has provided limited evidence for the involvement of the cytochrome P450 oxidase EryFAc (derived from Ac. erythraea YIM90600) in the catalysis of a two-step oxidation, resulting in an epoxy moiety, the attempt to construct an EH-producing Sa. erythraea mutant via gene complementation was not successful. Characterization of EryKAc (derived from Ac. erythraea YIM90600) in vitro has confirmed its unique role as a C-12 hydroxylase, rather than a C-14 hydroxylase of the erythronolide. Genomic characterization of the halophile Ac. erythraea YIM90600 will assist us to explore the great potential of extremophiles, and promote the understanding of EH formation, which will shed new insights into the biosynthesis of Er metabolites.
authors.affiliation: Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou, China; Huzhou Center of Bio-synthetic Innovation, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Huzhou, China.
authors.forename: Dandan
authors.initials: D
authors.lastname: Chen
authors.affiliation: Huzhou Center of Bio-synthetic Innovation, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Huzhou, China.
authors.forename: Junyin
authors.initials: J
authors.lastname: Feng
authors.affiliation: Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Huang
authors.affiliation: Huzhou Center of Bio-synthetic Innovation, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Huzhou, China.
authors.forename: Qinglin
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Huzhou Center of Bio-synthetic Innovation, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Huzhou, China.
authors.forename: Jiequn
authors.initials: J
authors.lastname: Wu
authors.affiliation: Hunan Engineering Research Center of Combinatorial Biosynthesis and Natural Product Drug Discovery, Changsha, Hunan, China; Xiangya International Academy of Translational Medicine, Central South University, Changsha, Hunan, China.
authors.forename: Xiangcheng
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Hunan Engineering Research Center of Combinatorial Biosynthesis and Natural Product Drug Discovery, Changsha, Hunan, China; Xiangya International Academy of Translational Medicine, Central South University, Changsha, Hunan, China.
authors.forename: Yanwen
authors.initials: Y
authors.lastname: Duan
authors.affiliation: Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou, China.
authors.forename: Zhinan
authors.initials: Z
authors.lastname: Xu
mesh_terms: D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D053898:Biosynthetic Pathways; D004917:Erythromycin / Q000031:analogs & derivatives* / Q000378:metabolism; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D005810:Multigene Family; D016930:Saccharopolyspora / Q000235:genetics* / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; C539663:erythronolide H; C539664:erythronolide I; C034277:6-deoxyerythronolide B; D004917:Erythromycin; D001189:Aryl Hydrocarbon Hydroxylases