Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi, Ishikawa, 921-8836, Japan.
Department of Food and Nutrition, Japan Women's University, Bunkyo-ku, Tokyo, 112-8681, Japan.
Microb Cell Fact. 2021 Oct 9;20(1):194. doi: 10.1186/s12934-021-01683-3.
Members of the genus Planococcus have been revealed to utilize and degrade solvents such as aromatic hydrocarbons and alkanes, and likely to acquire tolerance to solvents. A yellow marine bacterium Planococcus maritimus strain iso-3 was isolated from an intertidal sediment that looked industrially polluted, from the Clyde estuary in the UK. This bacterium was found to produce a yellow acyclic carotenoid with a basic carbon 30 (C) structure, which was determined to be methyl 5-glucosyl-5,6-dihydro-4,4'-diapolycopenoate. In the present study, we tried to isolate and identify genes involved in carotenoid biosynthesis from this marine bacterium, and to produce novel or rare C-carotenoids with anti-oxidative activity in Escherichia coli by combinations of the isolated genes.
A carotenoid biosynthesis gene cluster was found out through sequence analysis of the P. maritimus genomic DNA. This cluster consisted of seven carotenoid biosynthesis candidate genes (orf1-7). Then, we isolated the individual genes and analyzed the functions of these genes by expressing them in E. coli. The results indicated that orf2 and orf1 encoded 4,4'-diapophytoene synthase (CrtM) and 4,4'-diapophytoene desaturase (CrtNa), respectively. Furthermore, orf4 and orf5 were revealed to code for hydroxydiaponeurosporene desaturase (CrtNb) and glucosyltransferase (GT), respectively. By utilizing these carotenoid biosynthesis genes, we produced five intermediate C-carotenoids. Their structural determination showed that two of them were novel compounds, 5-hydroxy-5,6-dihydro-4,4'-diaponeurosporene and 5-glucosyl-5,6-dihydro-4,4'-diapolycopene, and that one rare carotenoid 5-hydroxy-5,6-dihydro-4,4'-diapolycopene is included there. Moderate singlet oxygen-quenching activities were observed in the five C-carotenoids including the two novel and one rare compounds.
The carotenoid biosynthesis genes from P. maritimus strain iso-3, were isolated and functionally identified. Furthermore, we were able to produce two novel and one rare C-carotenoids in E. coli, followed by positive evaluations of their singlet oxygen-quenching activities.
已发现棒杆菌属的成员能够利用和降解芳烃和烷烃等溶剂，并且可能具有对溶剂的耐受性。一种黄色海洋细菌 Planococcus maritimus 菌株 iso-3 是从看起来受到工业污染的潮间带沉积物中分离出来的，该沉积物来自英国克莱德河口。该细菌被发现产生一种具有基本碳 30 (C) 结构的黄色无环类胡萝卜素，该类胡萝卜素被确定为甲基 5-葡萄糖基-5,6-二氢-4,4'-二聚多烯酸酯。在本研究中，我们试图从这种海洋细菌中分离和鉴定参与类胡萝卜素生物合成的基因，并通过组合分离的基因在大肠杆菌中产生具有抗氧化活性的新型或罕见 C-类胡萝卜素。
通过对 P. maritimus 基因组 DNA 的序列分析，发现了一个类胡萝卜素生物合成基因簇。该簇由七个类胡萝卜素生物合成候选基因（orf1-7）组成。然后，我们分离了各个基因，并通过在大肠杆菌中表达这些基因来分析它们的功能。结果表明，orf2 和 orf1 分别编码 4,4'-二脱叶红素合酶（CrtM）和 4,4'-二脱叶红素脱氢酶（CrtNa）。此外，orf4 和 orf5 被揭示分别编码羟脱叶红素脱氢酶（CrtNb）和葡萄糖基转移酶（GT）。通过利用这些类胡萝卜素生物合成基因，我们产生了五种中间 C-类胡萝卜素。它们的结构确定表明，其中两种是新化合物，5-羟基-5,6-二氢-4,4'-二脱叶红素和 5-葡萄糖基-5,6-二氢-4,4'-二聚多烯，其中一种罕见的类胡萝卜素 5-羟基-5,6-二氢-4,4'-二聚多烯也包括在内。在包括两种新化合物和一种罕见化合物在内的五种 C-类胡萝卜素中观察到适度的单线态氧猝灭活性。
从 P. maritimus 菌株 iso-3 中分离出类胡萝卜素生物合成基因，并对其功能进行了鉴定。此外，我们能够在大肠杆菌中产生两种新型和一种罕见的 C-类胡萝卜素，并对它们的单线态氧猝灭活性进行了积极评价。
