title: Overproduction of lactimidomycin by cross-overexpression of genes encoding Streptomyces antibiotic regulatory proteins.
abstract: The glutarimide-containing polyketides represent a fascinating class of natural products that exhibit a multitude of biological activities. We have recently cloned and sequenced the biosynthetic gene clusters for three members of the glutarimide-containing polyketides-iso-migrastatin (iso-MGS) from Streptomyces platensis NRRL 18993, lactimidomycin (LTM) from Streptomyces amphibiosporus ATCC 53964, and cycloheximide (CHX) from Streptomyces sp. YIM56141. Comparative analysis of the three clusters identified mgsA and chxA, from the mgs and chx gene clusters, respectively, that were predicted to encode the PimR-like Streptomyces antibiotic regulatory proteins (SARPs) but failed to reveal any regulatory gene from the ltm gene cluster. Overexpression of mgsA or chxA in S. platensis NRRL 18993, Streptomyces sp. YIM56141 or SB11024, and a recombinant strain of Streptomyces coelicolor M145 carrying the intact mgs gene cluster has no significant effect on iso-MGS or CHX production, suggesting that MgsA or ChxA regulation may not be rate-limiting for iso-MGS and CHX production in these producers. In contrast, overexpression of mgsA or chxA in S. amphibiosporus ATCC 53964 resulted in a significant increase in LTM production, with LTM titer reaching 106 mg/L, which is five-fold higher than that of the wild-type strain. These results support MgsA and ChxA as members of the SARP family of positive regulators for the iso-MGS and CHX biosynthetic machinery and demonstrate the feasibility to improve glutarimide-containing polyketide production in Streptomyces strains by exploiting common regulators.
authors.affiliation: School of Life Sciences, Northeast Agricultural University, Harbin, Heilongjiang, 150030, China.|Department of Chemistry, The Scripps Research Institute, Jupiter, FL, 33458, USA.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, The Scripps Research Institute, Jupiter, FL, 33458, USA.
authors.forename: Dong
authors.initials: D
authors.lastname: Yang
authors.affiliation: School of Life Sciences, Northeast Agricultural University, Harbin, Heilongjiang, 150030, China.|Department of Chemistry, The Scripps Research Institute, Jupiter, FL, 33458, USA.
authors.forename: Yijun
authors.initials: Y
authors.lastname: Yan
authors.affiliation: Department of Chemistry, The Scripps Research Institute, Jupiter, FL, 33458, USA.
authors.forename: Guohui
authors.initials: G
authors.lastname: Pan
authors.affiliation: School of Life Sciences, Northeast Agricultural University, Harbin, Heilongjiang, 150030, China. xiangwensheng@neau.edu.cn.
authors.forename: Wensheng
authors.initials: W
authors.lastname: Xiang
authors.affiliation: Department of Chemistry, The Scripps Research Institute, Jupiter, FL, 33458, USA. shenb@scripps.edu.|Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL, 33458, USA. shenb@scripps.edu.|Natural Products Library Initiative at The Scripps Research Institute, The Scripps Research Institute, Jupiter, FL, 33458, USA. shenb@scripps.edu.
authors.forename: Ben
authors.initials: B
authors.lastname: Shen
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism*; D015870:Gene Expression; D005809:Genes, Regulator; D018942:Macrolides / Q000378:metabolism*; D010881:Piperidones / Q000378:metabolism*; D013302:Streptomyces / Q000235:genetics* / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D018942:Macrolides; D010881:Piperidones; C077633:lactimidomycin
keywords: Antibiotic titer improvement; Biosynthesis; Glutarimide-containing polyketides; Regulation; Streptomyces antibiotic regulatory proteins