Identification and Characterization of a New Erythromycin Biosynthetic Gene Cluster in Actinopolyspora Erythraea YIM90600, a Novel Erythronolide-Producing Halophilic Actinomycete Isolated From Salt Field

PLoS One. 2014 Sep 24;9(9):e108129. doi: 10.1371/journal.pone.0108129. eCollection 2014.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aryl Hydrocarbon Hydroxylases / genetics
  • Aryl Hydrocarbon Hydroxylases / metabolism
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Biosynthetic Pathways
  • Erythromycin / analogs & derivatives*
  • Erythromycin / metabolism
  • Genes, Bacterial
  • Molecular Sequence Data
  • Multigene Family*
  • Saccharopolyspora / genetics*
  • Saccharopolyspora / metabolism*

Substances

  • Bacterial Proteins
  • erythronolide H
  • erythronolide I
  • 6-deoxyerythronolide B
  • Erythromycin
  • Aryl Hydrocarbon Hydroxylases

Associated data

  • GENBANK/JPMV00000000
  • GENBANK/KJ143518
  • GENBANK/KJ143519
  • GENBANK/KJ143520

Grant support

This work was supported in part by grants from the National Natural Science Foundation of China (21176214, 20832009, and 91213303), the National High Technology Research and Development Program of China (2012AA02A705, 2012AA022105A and 2011AA02A114), “973 program” (2010CB833200 and 2012CB721100), the Chinese Ministry of Education 111 Project B08034, and CAS (KJCX2-YW-H201) of China. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.