Department of Life Science and Biochemical Engineering, Institute of Biomolecule Reconstruction (iBR), Sun Moon University, Asan 31460, Republic of Korea.
Central Department of Chemistry, Tribhuvan University, Kirtipur, Kathmandu 44618, Nepal.
Int J Mol Sci. 2024 Aug 14;25(16):8847. doi: 10.3390/ijms25168847.
The identification of specialized metabolites isolated from microorganisms is urgently needed to determine their roles in treating cancer and controlling multidrug-resistant pathogens. Naphthoquinones act as anticancer agents in various types of cancers, but some toxicity indicators have been limited in their appropriate application. In this context, new isofuranonaphthoquinones (ifnq) that are less toxic to humans could be promising lead compounds for developing anticancer drugs. The aim of this study is to identify and characterize novel furanonaphthoquinones (fnqs) from sp. CS682 and to evaluate their potential therapeutic applications. Analysis of the genome of sp. CS682 revealed the presence of a furanonaphthoquinone () gene cluster, which displays a similar genetic organization and high nucleotide sequence identity to the gene cluster from sp. RI-77, a producer of the naphthoquinones JBIR-76 and JBIR-77. In this study, the overexpression of the antibiotic regulatory protein (SARP) in sp. CS682DR (nargenicin gene-deleted mutant) explicitly produced new fnqs, namely, NOC-IBR1 and NOC-IBR2. Subsequently, the role of the SARP regulator was confirmed by gene inactivation using CRISPR-Cas9 and complementation studies. Furthermore, antioxidant, antimicrobial, and cytotoxicity assays were performed for the isolated compounds, and it was found that NOC-IBR2 exhibited superior activities to NOC-IBR1. In addition, a flexible methyltransferase substrate, ThnM3, was found to be involved in terminal methylation of NOC-IBR1, which was confirmed by in vitro enzyme assays. Thus, this study supports the importance of genome mining and genome editing approaches for exploring new specialized metabolites in a rare actinomycete called .
从微生物中分离的特征代谢产物的鉴定对于确定其在治疗癌症和控制多药耐药病原体中的作用至关重要。萘醌类化合物在各种类型的癌症中都具有抗癌作用，但一些毒性指标限制了它们的适当应用。在这种情况下，对人类毒性较小的新型异呋喃萘醌（ifnq）可能成为开发抗癌药物的有前途的先导化合物。本研究旨在从 sp. CS682 中鉴定和表征新型呋喃萘醌（fnq），并评估其潜在的治疗应用。sp. CS682 基因组的分析显示存在呋喃萘醌（）基因簇，该基因簇显示出与来自 sp. RI-77 的萘醌基因簇相似的遗传组织和高核苷酸序列同一性，后者是萘醌 JBIR-76 和 JBIR-77 的产生菌。在本研究中，在 sp. CS682DR（nargenicin 基因缺失突变体）中过表达抗生素调节蛋白（SARP）明确产生了新的 fnqs，即 NOC-IBR1 和 NOC-IBR2。随后，通过 CRISPR-Cas9 基因失活和互补研究证实了 SARP 调节剂的作用。此外，还对分离得到的化合物进行了抗氧化、抗菌和细胞毒性测定，发现 NOC-IBR2 的活性优于 NOC-IBR1。此外，还发现了一种灵活的甲基转移酶底物 ThnM3，它参与了 NOC-IBR1 的末端甲基化，这通过体外酶测定得到了证实。因此，本研究支持了对稀有放线菌进行基因组挖掘和基因组编辑以探索新型特征代谢产物的重要性，该放线菌名为 。
