Open AccessNystatin Biosynthesis and Transport: nysH and nysG Genes Encoding a Putative ABC Transporter System in Streptomyces noursei ATCC 11455 Are Required for Efficient Conversion of 10-Deoxynystatin to Nystatin
Author(s) -
Håvard Sletta,
Sven Even F. Borgos,
Per Bruheim,
Olga N. Sekurova,
Hans Grasdalen,
Randi Aune,
Trond E. Ellingsen,
Sergey B. Zotchev
Publication year - 2005
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.49.11.4576-4583.2005
Subject(s) - nystatin , efflux , atp binding cassette transporter , biochemistry , mutant , biology , metabolite , hydroxylation , membrane transport protein , biosynthesis , transporter , chemistry , microbiology and biotechnology , gene , antibiotics , enzyme
The genesnysH andnysG , encoding putative ABC-type transporter proteins, are located at the flank of the nystatin biosynthetic gene cluster inStreptomyces noursei ATCC 11455. To assess the possible roles of these genes in nystatin biosynthesis, they were inactivated by gene replacements leading to in-frame deletions. Metabolite profile analysis of thenysH andnysG deletion mutants revealed that both of them synthesized nystatin at a reduced level and produced considerable amounts of a putative nystatin analogue. Liquid chromatography-mass spectrometry and nuclear magnetic resonance structural analyses of the latter metabolite confirmed its identity as 10-deoxynystatin, a nystatin precursor lacking a hydroxyl group at C-10. Washing experiments demonstrated that both nystatin and 10-deoxynystatin are transported out of cells, suggesting the existence of an alternative efflux system(s) for the transport of nystatin-related metabolites. This notion was further corroborated in experiments with the ATPase inhibitor sodiumo -vanadate, which affected the production of nystatin and 10-deoxynystatin in the wild-type strain and transporter mutants in a different manner. The data obtained in this study suggest that the efflux of nystatin-related polyene macrolides occurs through several transporters and that the NysH-NysG efflux system provides conditions favorable for C-10 hydroxylation.