University of Helsinki, Department of Microbiology, Faculty of Agriculture and Forestry, 00014 Helsinki, Finland.
University of São Paulo, Center for Nuclear Energy in Agriculture, Avenida Centenário 303, 13400-970 Piracicaba, São Paulo, Brazil.
ACS Chem Biol. 2023 Sep 15;18(9):1959-1967. doi: 10.1021/acschembio.3c00112. Epub 2023 Aug 21.
Mycosporine-like amino acids (MAAs) are small, colorless, and water-soluble secondary metabolites. They have high molar extinction coefficients and a unique UV radiation absorption mechanism that make them effective sunscreens. Here we report the discovery of two structurally distinct MAAs from the lichen symbiont strain sp. UHCC 0926. We identified these MAAs as aplysiapalythine E (CHNO) and tricore B (CHNO) using a combination of high-resolution liquid chromatography-mass spectrometry (HR-LCMS) analysis and nuclear magnetic resonance (NMR) spectroscopy. We obtained a 8.3 Mb complete genome sequence of sp. UHCC 0926 to gain insights into the genetic basis for the biosynthesis of these two structural distinct MAAs. We identified MAA biosynthetic genes encoded in three separate locations of the genome. The organization of biosynthetic enzymes in sp. UHCC 0926 necessitates a branched biosynthetic pathway to produce two structurally distinct MAAs. We detected the presence of such discontiguous MAA biosynthetic gene clusters in 12% of the publicly available complete cyanobacterial genomes. Bioinformatic analysis of public MAA biosynthetic gene clusters suggests that they are subject to rapid evolutionary processes resulting in highly plastic biosynthetic pathways that are responsible for the chemical diversity in this family of microbial sunscreens.
Mycosporine-like amino acids (MAAs) 是一类小型、无色、水溶性的次生代谢产物。它们具有高摩尔消光系数和独特的紫外线辐射吸收机制，是有效的防晒霜。在这里，我们报告了从共生菌菌株 sp. UHCC 0926 中发现的两种结构不同的 MAAs。我们通过高分辨率液相色谱-质谱（HR-LCMS）分析和核磁共振（NMR）光谱鉴定了这些 MAAs 为 aplysiapalythine E（CHNO）和 tricore B（CHNO）。我们获得了 sp. UHCC 0926 的 8.3 Mb 完整基因组序列，以深入了解这两种结构不同 MAAs 生物合成的遗传基础。我们在基因组的三个不同位置鉴定了编码 MAA 生物合成基因。sp. UHCC 0926 中生物合成酶的组织需要一个分支生物合成途径来产生两种结构不同的 MAAs。我们在 12%的公开可用的完整蓝细菌基因组中检测到了这种不连续的 MAA 生物合成基因簇的存在。对公共 MAA 生物合成基因簇的生物信息学分析表明，它们经历了快速的进化过程，导致了高度可塑性的生物合成途径，这是该家族微生物防晒霜化学多样性的原因。
