Increased glycopeptide production after overexpression of shikimate pathway genes being part of the balhimycin biosynthetic gene cluster.
Amycolatopsis balhimycina produces the vancomycin-analogue balhimycin. The strain therefore serves as a model strain for glycopeptide antibiotic production. Previous characterisation of the balhimycin biosynthetic cluster had shown that the border sequences contained both, a putative 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase (dahp), and a prephenate dehydrogenase (pdh) gene. In a metabolic engineering approach for increasing the precursor supply for balhimycin production, the dahp and pdh genes from the biosynthetic cluster were overexpressed both individually and together and the resulting strains were subjected to quantitative physiological characterisation. The constructed strains expressing an additional copy of the dahp gene and the strain carrying an extra copy of both dahp and pdh showed improved specific glycopeptide productivities by approximately a factor three, whereas the pdh overexpression strain showed a production profile similar to the wild type strain. In addition to the overexpression strains, corresponding deletion mutants, Deltadahp and Deltapdh, were constructed and characterised. Deletion of dahp resulted in significant reduction in balhimycin production whereas the Deltapdh strain had production levels similar to the parent strain. Based on these results the relation between primary and secondary metabolism with regards to Dahp and Pdh is discussed.
Thykaer
Jette
J
Center for Microbial Biotechnology, Department of Systems Biology, Technical University of Denmark, Building 223, DK-2800 Lyngby, Denmark. jt@bio.dtu.dk
Nielsen
Jens
J
Wohlleben
Wolfgang
W
Weber
Tilmann
T
Gutknecht
Michael
M
Lantz
Anna E
AE
Stegmann
Evi
E
D000192:Actinomycetales / Q000378:metabolism*; D006020:Glycopeptides / Q000096:biosynthesis*; D005810:Multigene Family / Q000502:physiology*; D012765:Shikimic Acid / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D015854:Up-Regulation / Q000502:physiology
D006020:Glycopeptides; D012765:Shikimic Acid