Genome-guided discovery of two undescribed 6,6-spiroketal polyketides and stereochemical correction of bafilomycins P and Q from the marine-derived Streptomyces sp. SCSIO 66814
- PMID: 38636687
- DOI: 10.1016/j.phytochem.2024.114101
Genome-guided discovery of two undescribed 6,6-spiroketal polyketides and stereochemical correction of bafilomycins P and Q from the marine-derived Streptomyces sp. SCSIO 66814
Abstract
Bafilomycins are macrocyclic polyketides with intriguing structures and therapeutic value. Genomic analysis of Streptomyces sp. SCSIO 66814 revealed a type I polyketide synthase biosynthetic gene cluster (BGC), namely blm, which encoded bafilomycins and featured rich post-modification genes. The One strain many compounds (OSMAC) strategy led to the discovery of six compounds related to the blm BGC from the strain, including two previously undescribed 6,6-spiroketal polyketides, streptospirodienoic acids D (1) and E (2), and four known bafilomycins, bafilomycins P (3), Q (4), D (5), and G (6). The structures of 1 and 2 were determined by extensive spectroscopic analysis, quantum calculation, and biosynthetic analysis. Additionally, the absolute configurations of the 6/5/5 tricyclic ring moiety containing six consecutive chiral carbons in the putative structures of 3 and 4 were corrected through NOE analysis, DP4+ calculation, and single-crystal X-ray diffraction data. Bioinformatic analysis uncovered a plausible biosynthetic pathway for compounds 1-6, indicating that both streptospirodienoic acids and bafilomycins were derived from the same blm BGC. Additionally, sequence analysis revealed that the KR domains of module 2 from blm BGC was B1-type, further supporting the configurations of 1-4. Notably, compounds 3 and 4 displayed significant cytotoxic activities against A-549 human non-small cell lung cancer cells and HCT-116 human colon cancer cells.
Keywords: Bafilomycin; Biosynthesis; Cytotoxic activity; Streptomyces sp. SCSIO 66814; Streptospirodienoic acid.
Copyright © 2024. Published by Elsevier Ltd.
Conflict of interest statement
Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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