Department of Marine Biotechnology, Stazione Zoologica Anton Dohrn, CAP80121 Naples, Italy.
Department of Humanities, Università degli Studi Suor Orsola Benincasa, CAP80135 Naples, Italy.
Mar Drugs. 2020 May 1;18(5):237. doi: 10.3390/md18050237.
Microalgae, due to their huge taxonomic and metabolic diversity, have been shown to be a valuable and eco-friendly source of bioactive natural products. The increasing number of genomic and transcriptomic data will give a great boost for the study of metabolic pathways involved in the synthesis of bioactive compounds. In this study, we analyzed the presence of the enzymes involved in the synthesis of monogalactosyldiacylglycerols (MGDGs) and sulfoquinovosyldiacylglycerols (SQDG). Both compounds have important biological properties. MGDGs present both anti-inflammatory and anti-cancer activities while SQDGs present immunostimulatory activities and inhibit the enzyme glutaminyl cyclase, which is involved in Alzheimer's disease. The Ocean Global Atlas (OGA) database and the Marine Microbial Eukaryotic Transcriptome Sequencing Project (MMETSP) were used to search MGDG synthase (MGD), UDP-sulfoquinovose synthase (SQD1), and sulfoquinovosyltransferase (SQD2) sequences along microalgal taxa. 3D prediction analyses for the three enzymes were performed by Phyre2 server, while binding site predictions were performed by the COACH server. The analyzed enzymes are distributed across different taxa, which confirms the importance for microalgae of these two pathways for thylakoid physiology. MGD genes have been found across almost all analyzed taxa and can be separated in two different groups, similarly to terrestrial plant MGD. SQD1 and SQD2 genes are widely distributed along the analyzed taxa in a similar way to MGD genes with some exceptions. For Pinguiophyceae, Raphidophyceae, and Synurophyceae, only sequences coding for MGDG were found. On the contrary, sequences assigned to Ciliophora and Eustigmatophyceae were exclusively corresponding to SQD1 and SQD2. This study reports, for the first time, the presence/absence of these enzymes in available microalgal transcriptomes, which gives new insights on microalgal physiology and possible biotechnological applications for the production of bioactive lipids.
微藻由于其巨大的分类和代谢多样性，已被证明是生物活性天然产物的宝贵且环保的来源。越来越多的基因组和转录组数据将极大地推动参与生物活性化合物合成的代谢途径的研究。在这项研究中，我们分析了参与单半乳糖二酰基甘油（MGDG）和磺基奎诺二酰基甘油（SQDG）合成的酶的存在。这两种化合物都具有重要的生物学特性。MGDG 具有抗炎和抗癌活性，而 SQDGs 具有免疫刺激活性，并抑制参与阿尔茨海默病的谷氨酰胺环化酶。海洋全球图谱（OGA）数据库和海洋微生物真核转录组测序计划（MMETSP）被用于搜索微藻分类群中的 MGDG 合酶（MGD）、UDP-磺基奎诺糖合酶（SQD1）和磺基奎诺糖基转移酶（SQD2）序列。通过 Phyre2 服务器对这三种酶进行 3D 预测分析，而通过 COACH 服务器进行结合位点预测。分析的酶分布在不同的分类群中，这证实了这两条途径对类囊体生理学对微藻的重要性。MGD 基因几乎存在于所有分析的分类群中，可以分为两组，类似于陆地植物的 MGD。SQD1 和 SQD2 基因在分析的分类群中分布广泛，与 MGD 基因相似，但也有一些例外。对于平形藻门、红藻门和金藻门，只发现了编码 MGDG 的序列。相反，分配给纤毛门和黄藻门的序列仅对应于 SQD1 和 SQD2。本研究首次报告了这些酶在现有微藻转录组中的存在/缺失情况，为微藻生理学和生物活性脂质生产的可能生物技术应用提供了新的见解。
