Expression plasmids carrying different deoxysugar biosynthetic gene cassettes and the gene encoding a substrate-flexible glycosyltransferase DesVII were constructed and introduced into Streptomyces venezuelae YJ003 mutant strain bearing a deletion of a desosamine biosynthetic (des) gene cluster. The resulting recombinants produced macrolide antibiotic YC-17 analogs possessing unnatural sugars replacing native d-desosamine. These metabolites were isolated and further purified using chromatographic techniques and their structures were determined as d-quinovosyl-10-deoxymethynolide, l-rhamnosyl-10-deoxymethynolide, l-olivosyl-10-deoxymethynolide, and d-boivinosyl-10-deoxymethynolide on the basis of 1D and 2D NMR and MS analyses and the stereochemistry of sugars was confirmed using coupling constant values and NOE correlations. Their antibacterial activities were evaluated in vitro against erythromycin-susceptible and -resistant Enterococcus faecium and Staphylococcus aureus. Substitution with l-rhamnose displayed better antibacterial activity than parent compound YC-17 containing native sugar d-desosamine. The present study on relationships between chemical structures and antibacterial activities could be useful in generation of novel advanced antibiotics utilizing combinatorial biosynthesis approach.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government Ministry of Education, Science and Technology (MEST) ( 20110018617 , 20110001340 , and 2011K000441 ); and the Intelligent Synthetic Biology Center of Global Frontier Project funded by the MEST ( 2011-0031961 ). This research was also supported by the Ewha Global Top5 Grant 2012 of Ewha Womans University . The bacterial strains were provided by the National Biobank of Korea – Kyungpook National University Hospital, which is supported by the Ministry of Health, Welfare and Family Affairs, and were obtained with informed consent under institutional review board-approved protocols.
- Combinatorial biosynthesis
- Streptomyces venezuelae
ASJC Scopus subject areas
- Applied Microbiology and Biotechnology