Identification and characterization of the geranylgeranyl diphosphate synthase in Deinococcus radiodurans
Identification and characterization of the geranylgeranyl diphosphate synthase in Deinococcus radiodurans
复制标题
耐辐射奇球菌中香叶基香叶基二磷酸合酶的鉴定和表征
DOI：
10.1111/lam.12181
复制
发表时间：
2014-03-01
影响因子：
2.4
通讯作者：
Hua, Y.
中科院分区：
文献类型：
--
作者：
Liu, C.;Sun, Z.;Hua, Y.
耐辐射异常球菌菌株R1利用多种抗氧化剂，包括一种独特的类胡萝卜素，脱黄质，再次对抗氧化应激。大多数参与脱黄质生物合成途径的酶已经被鉴定。然而，催化合成香叶基香叶基二磷酸（GGPP）的酶，这是类胡萝卜素生物合成的前体，尚未被确定。通过保守氨基酸序列分析，筛选出两个IPPS同源物（DR1395和DR932），并对其生化功能进行了研究。利用基因突变、大肠杆菌表达和类胡萝卜素产物分析等方法对这些候选物的功能进行了研究。结果表明，DR1395编码GGPP合成蛋白。定点突变体分析表明，氨基酸组成和周围的第一个富含精氨酸的基序是至关重要的GGPP synthase function.Significance和影响的StudyDeinococcus radiodurans菌株R1产生一种独特的类胡萝卜素产品，脱黄质，作为抗氧化剂。在这项研究中，DR1395被确定为基因编码香叶基香叶基二磷酸合酶（GGPPS）的入口脱黄质生物合成的耐辐射D.。此外，对DR1395的定点诱变研究确定了富含谷氨酸基序的氨基酸组成对该类胡萝卜素产生的影响。本研究证实了脱黄质生物合成途径中的入口步骤。这些结果可以是有用的基因工程策略，包括增强GGPPS基因的表达，耐辐射的脱黄素生产。
Deinococcus radiodurans strain R1 utilizes multiple antioxidants including a unique carotenoid, deinoxanthin, to fight again oxidative stress. Most of the enzymes involved in the deinoxanthin biosynthetic pathway have been identified. However, the enzyme catalysing the synthesis of geranylgeranyl diphosphate (GGPP), which is a precursor of carotenoid biosynthesis, has yet to be identified. Two putative isoprenyl diphosphate synthases (IPPS) homologues (DR1395 and DR932) were screened out by analysis of conserved amino acid regions, and their biochemical functions were investigated. Gene mutation, gene expression in Escherichia coli and analysis of carotenoid products were used to investigate the functions of these candidates. The results suggested that DR1395 encodes the protein for GGPP synthesis. Site-directed mutant analysis indicated that the amino acid composition of and around the first aspartate-rich motif is vital for GGPP synthase function.Significance and Impact of the StudyDeinococcus radiodurans strain R1 produces a unique carotenoid product, deinoxanthin, as an antioxidant. In this study, DR1395 was identified as the gene encoding geranylgeranyl diphosphate synthase (GGPPS) for entrance to deinoxanthin biosynthesis in D.radiodurans. Moreover, site-directed mutagenesis studies on DR1395 identified the effect of amino acid composition of the aspartate-rich motif on the production of this carotenoid. This study demonstrated the entrance step in the deinoxanthin biosynthetic pathway. These results can be useful in genetic engineering strategies for deinoxanthin production including enhancement of GGPPS gene expression in D.radiodurans.