Targeted isolation of cyclicoctapeptide surugamides produced by Streptomyces NA13 and exploration of their plant growth-promoting activities supplementary material

Figure S1 illustrates the isolation flowchart of cyclic octapeptide compounds 1–4 guided by chemical structural characteristics. The isolation process was performed with reference to the fermentation and post‑processing procedures of the strain reported in Reference 10.Table S1 shows the secondary metabolite biosynthetic gene clusters of Streptomyces sp. NA13 identified by genome mining. The non‑ribosomal peptide synthetase (NRPS)‑type secondary metabolite biosynthetic gene clusters were predicted and analyzed using updated online tools such as antiSMASH 8.0 and FramePlot 8.0 beta.Table S2 presents the node assignments of the partial molecular network of Streptomyces sp. NA13. The active crude extract was further analyzed by high‑performance liquid chromatography coupled with Q Exactive tandem mass spectrometry (HPLC‑Q Exactive MS/MS). Tandem mass spectrometry data were first collected, and the raw LC‑MS/MS data files were converted into .mzXML format using MSConver software, followed by uploading to the Global Natural Products Social Molecular Networking database. The results were visualized using Cytoscape software.The constructed molecular network was analyzed with the aid of the Global Natural Products Social Molecular Networking data platform to target the "cyclopeptide family" molecular clusters exhibiting amino acid fragmentation rules. The nodes in the "cyclopeptide family" molecular clusters were analyzed, and the differences in MS/MS mass spectrometry data among related nodes were compared, thereby generating Table S2.Table S3 summarizes the variable amino acid substrates recognized by the A‑domains in SurA. Genome‑wide analysis of the A‑domains via antiSMASH 8.0 indicated that they possess substrate promiscuity, and the recognizable substrates include leucine, isoleucine, valine, etc. (Table S3).