岩藻黄质关键前体新黄质的代谢工程合成

Metabolic engineering synthesis of neoxanthin, a key precursor of fucoxanthin

  • 摘要: 岩藻黄质是海洋藻类中常见的叶黄素之一,尤其在褐藻中含量较高,具有抑菌、抗炎、抗肥胖、抗糖尿病、抗肿瘤、调节肠道菌群和抗器官纤维化等多种生理活性。新黄质是岩藻黄质的可能前体物质,首次在大肠杆菌 (Escherichia coli) 中构建新黄质合成途径,首先构建了pTrc99a-crtEBIYZ质粒,该质粒携带5个来自于菠萝泛菌 (Pantoea ananatis) 的基因crtEcrtBcrtIcrtYcrtZ,编码的蛋白分别是牻牛儿基牻牛儿基焦磷酸合成酶、八氢番茄红素合成酶、八氢番茄红素脱氢酶、番茄红素环化酶和β-胡萝卜素羟化酶。将该质粒转入大肠杆菌中,得到了产玉米黄质的工程菌E. coli BL21 pTrc99a-crtEBIYZ,玉米黄质产量 (细胞干质量,下同) 为0.70 mg·g−1。以产玉米黄质工程菌为宿主,将来自三角褐指藻 (Phaeodactylum tricornutum) 的ZEP3基因去信号肽之后转入,得到产紫黄质的工程菌E. coli BL21 pTrc99a-crtEBIYZ pACYCDuet-1-QZEP3。在紫黄质工程菌E. coli BL21 pTrc99a-crtEBIYZ pACYCDuet-1-QZEP3的基础上转入新黄质合酶基因NSY,成功获得了产新黄质的工程菌E. coli BL21 NEO,新黄质产量为99.27 μg·g−1 ,紫黄质产量为150.30 μg·g−1,玉米黄质产量为119.77 μg·g−1

     

    Abstract: Fucoxanthin is one of the common luteins in marine algae, especially in brown algae, which has antibacterial, anti-inflammatory, anti-obesity, anti-diabetes, anti-cancer, regulating intestinal flora, anti-organ fibrosis and other physiological activities. Neoxanthin is a possible precursor of fucoxanthin. In this paper, we constructed a neoxanthin synthesis pathway in Escherichia coli for the first time and the plasmid pTrc99a-crtEBIYZ, which carries five genes (crtE, crtB, crtI, crtY and crtZ) from Pantoea ananatis, and codes for proteins (geranylgeranyl pyrophosphate synthase, phytoene synthase, lycopene cyclase and β-carotene hydroxylase). We transferred the plasmid into E. coli, and obtained the zeaxanthin-producing E. coli BL21 pTrc99a-crtEBIYZ. The yield of zeaxanthin (dry cell mass) was 0.70 mg·g−1. We obtained E. coli pTrc99a-crtEBIYZ pACYCDuet-1-QZEP3 strain by transferring ZEP3 gene from Phaeodactylum tricornutum without signal peptide, and obtained E. coli BL21 NEO successfully by transferring the neoxanthin synthase gene NSY into E. coli BL21 pTrc99a-crtEBIYZ pACYCDuet-1-QZEP3. The concentrations of neoxanthin, violaxanthin and zeaxanthin were 99.27, 150.30 and 119.77 μg·g−1 dry cell mass, respectively.

     

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