海鞘来源放线菌Streptomyces pratensis SCSIO LCY05中skyllamycins的发现及其生物合成分析

目的 挖掘海鞘来源放线菌 Streptomyces pratensis SCSIO LCY05生产含肉桂酰独特结构单元的skyllamycins类环肽的潜能,并深入分析skyllamycins生物合成基因簇的新特征.方法 利用Illumina Hiseq和Pacbio SMRT测序平台对S.pratensis SCSI...

Discovery and biosynthetic analysis of skyllamycins from Streptomyces pratensis SCSIO LCY05 derived from Ascidian

Objective To investigate the potential of cinnamyl structural unit containing skyllamycins production in Streptomyces pratensis SCSIO LCY05 derived from ascidian and analyze the new characteristics of skyllamycins biosynthetic gene cluster (skl BGC). Methods The whole genome of S. pratensis SCSIO LCY05 was sequenced using the Illumina Hiseq and PacBio SMRT platform, and the biosynthetic gene clusters of the secondary meatbolites were predicted and the functions of ORFs in the biosynthetic gene cluster were annotated by online bioinformatic softwares. The one strain many compounds (OSMAC) strategy was used to conduct the fermentation optimization of S. pratensis SCSIO LCY05. The secondary metabolites of the strain were isolated and structurally characterized by extraction, chromatography and spectroscopic data analyses, etc. The biosynthetic pathway and novel biosynthetic characteristics of the obtained compounds were analyzed. Results The whole genome sequencing results showed that the genome size of S. pratensis SCSIO LCY05 is 8.42 Mbp, containing a total of 35 biosynthetic gene clusters. The 20th gene cluster on the genome is 95% similar to the reported skyllamycins biosynthetic gene cluster and predicted to charge for the biosynthesis of cinnamyol unit containing natural products in S. pratensis SCSIO LCY05. Based on the OSMAC strategy, two peaks with typical absorption characteristics were found in SCAS medium of S. pratensis SCSIO LCY05, which were identified as skyllamycin A and skyllamycin B. The biosynthetic pathway of skyllamycin A and B was analyzed in detail. Further sequence alignment indicated that the C11 domain on skyllamycin assembly line is a special domain with dual functions that responsible for the condensation and epimerization of the 11th amino acid in skyllamycin. Concluison In this study, we found that thecyclic peptides skyllamycins can be produced in S. pratensis SCSIO LCY05 by OSMAC strategy, and discovered new characteristics in its biosynthetic assembly line. Notably, this study also provided a new strain resource for the indepth elucidation of the biosynthetic mechanism of skyllamycins and subsequent development and utilization.