title: A Branch Point of Streptomyces Sulfur Amino Acid Metabolism Controls the Production of Albomycin.
abstract: Albomycin (ABM), also known as grisein, is a sulfur-containing metabolite produced by Streptomyces griseus ATCC 700974. Genes predicted to be involved in the biosynthesis of ABM and ABM-like molecules are found in the genomes of other actinomycetes. ABM has potent antibacterial activity, and as a result, many attempts have been made to develop ABM into a drug since the last century. Although the productivity of S. griseus can be increased with random mutagenesis methods, understanding of Streptomyces sulfur amino acid (SAA) metabolism, which supplies a precursor for ABM biosynthesis, could lead to improved and stable production. We previously characterized the gene cluster (abm) in the genome-sequenced S. griseus strain and proposed that the sulfur atom of ABM is derived from either cysteine (Cys) or homocysteine (Hcy). The gene product, AbmD, appears to be an important link between primary and secondary sulfur metabolic pathways. Here, we show that propargylglycine or iron supplementation in growth media increased ABM production by significantly changing the relative concentrations of intracellular Cys and Hcy. An SAA metabolic network of S. griseus was constructed. Pathways toward increasing Hcy were shown to positively impact ABM production. The abmD gene and five genes that increased the Hcy/Cys ratio were assembled downstream of hrdBp promoter sequences and integrated into the chromosome for overexpression. The ABM titer of one engineered strain, SCAK3, in a chemically defined medium was consistently improved to levels ∼400% of the wild type. Finally, we analyzed the production and growth of SCAK3 in shake flasks for further process development.
authors.affiliation: Department of Biological Sciences, Ohio University, Athens, Ohio, USA.
authors.forename: Aditya
authors.initials: A
authors.lastname: Kulkarni
authors.affiliation: Department of Biological Sciences, Ohio University, Athens, Ohio, USA.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zeng
authors.affiliation: Department of Biological Sciences, Ohio University, Athens, Ohio, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.affiliation: Department of Pharmaceutical Sciences, University of Kentucky College of Pharmacy, Lexington, Kentucky, USA.
authors.forename: Steven
authors.initials: S
authors.lastname: Van Lanen
authors.affiliation: Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin, People's Republic of China.
authors.forename: Weiwen
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Biological Sciences, Ohio University, Athens, Ohio, USA schen169@hotmail.com.
authors.forename: Shawn
authors.initials: S
authors.lastname: Chen
mesh_terms: D000603:Amino Acids, Sulfur / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000096:biosynthesis*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D005291:Ferrichrome / Q000031:analogs & derivatives* / Q000378:metabolism; D005810:Multigene Family; D013305:Streptomyces griseus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
chemical_list: D000603:Amino Acids, Sulfur; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D005291:Ferrichrome; C015657:albomycin