Identification and functional analysis of a phytoene desaturase gene from the extremely radioresistant bacterium Deinococcus radiodurans
Identification and functional analysis of a phytoene desaturase gene from the extremely radioresistant bacterium Deinococcus radiodurans
复制标题
极耐辐射细菌耐辐射奇球菌八氢番茄红素去饱和酶基因的鉴定和功能分析
DOI：
10.1099/mic.0.2006/002857-0
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发表时间：
2007-05-01
期刊：
影响因子：
2.8
通讯作者：
Hua, Yuejin
中科院分区：
文献类型：
--
作者：
Xu, Zhenjian;Tian, Bing;Hua, Yuejin
The phytoene-related desaturases are the key enzymes in the carotenoid biosynthetic pathway. The gene encoding phytoene desaturase in the deinoxanthin synthesis pathway of Deinococcus radiodurans was identified and characterized. Two putative phytoene desaturase homologues (DR0861 and DR0810) were identified by analysis of conserved amino acid regions, and the former displayed the highest identity (68 %) with phytoene desaturase of the cyanobacterium Gloeobacter violaceus. DR0861 gene knockout and dinucleotide-binding motif deletion resulted in the arrest of lycopene synthesis and the accumulation of phytoene. The colourless DROB61 knockout mutant became more sensitive to acute ionizing radiation and oxygen stress.Complementation of the mutant with a heterologous or homologous gene restored its pigment and resistance. The desaturase activity of DR0861 (crtl) was further confirmed by the assay of enzyme activity in vitro and heterologous expression in Escherichia coli containing crtE and crtB genes (responsible for phytoene synthesis) from Erwinia uredovora. In addition, the amount of lycopene synthesis in E coli resulting from the expression of crtl from D. radiodurans was determined, and this had significant dose-dependent effects on the survival rate of E coli exposed to hydrogen peroxide and ionizing radiation.
