Bioinformatics-Inspired Isolation of Akaemycin, a New Macrolide from Marine <i>Streptomyces</i> sp.

Abstract

Background: Investigation of products from marine Streptomyces sp. NPS554 led to the discovery of lorneic acids and akaeolide. Genome analysis of this strain predicted the presence of more unidentified secondary metabolites. In this study, we further examined the products of strain NPS554 to obtain novel compounds predicted by bioinfomatical screening. Methods: Culture extract of strain NPS554 was fractionated by different chromatography methods. The chemical structure was elucidated by spectroscopic analysis. The absolute configuration was further determined by PKS gene analysis. Antimicrobial assay was conducted to evaluate the biological activity of the new compound. Results & Conclusion: Akaemycin, a novel macrolide compound was isolated as a yellow amorphous solid. Its structure was elucidated by MS and NMR spectroscopic analyses. Its spectroscopically defined structure was consistent with the structure predicted from the annotation of orphan type I PKS gene clusters in the NPS554 genome. Stereochemistry of akaemycin was proposed on the basis of ROESY and bioinformatical analysis. Antimicrobial assay showed activity against Gram-positive bacteria and filamentous fungi. Keywords: macrolide, marine Streptomyces, polyketide, PKS.