Identification of a novel vinyl reductase gene essential for the biosynthesis of monovinyl chlorophyll in Synechocystis sp PCC6803
Identification of a novel vinyl reductase gene essential for the biosynthesis of monovinyl chlorophyll in Synechocystis sp PCC6803
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DOI：
10.1074/jbc.m708369200
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发表时间：
2008-04-04
影响因子：
4.8
通讯作者：
Tanaka, Ayumi
中科院分区：
文献类型：
--
作者：
Ito, Hisashi;Yokono, Makio;Tanaka, Ayumi
绝大多数产氧光合作用生物利用单乙烯基叶绿素进行光合作用。对于这种类型的叶绿素的生物合成，位于大环B环上的8-乙烯基团的减少是必不可少的。以前，我们在高等植物中发现了编码8-乙烯基还原酶的基因，并将其命名为DVR。在已测序的蓝藻基因组中，只有几种聚球藻含有DVR同源物。因此，许多其他产生单乙烯基叶绿素的蓝藻应该含有一种与高等植物DVR无关的乙烯基还原酶。为了确定负责单烯基叶绿素合成的蓝藻基因，我们开发了一个生物信息学工具--相关系数计算工具，它计算某一表型的分布与一组生物之间的基因之间的相关系数。该程序表明，编码可能的脱氢酶蛋白的基因的分布与无DVR的蓝藻的分布最相关。随后，我们在集胞藻中敲除了相应的基因(Slr1923)。PCC6803，并对突变体进行了鉴定。该敲除突变体失去了合成单乙烯基叶绿素的能力，而是积累了3，8-二乙烯基叶绿素。我们得出结论，Slr1923编码乙烯基还原酶或单乙烯基叶绿素合成所必需的一个亚基。对8-乙烯基还原酶基因的功能和进化进行了讨论。
The vast majority of oxygenic photosynthetic organisms use monovinyl chlorophyll for their photosynthetic reactions. For the biosynthesis of this type of chlorophyll, the reduction of the 8-vinyl group that is located on the B-ring of the macrocycle is essential. Previously, we identified the gene encoding 8-vinyl reductase responsible for this reaction in higher plants and termed it DVR. Among the sequenced genomes of cyanobacteria, only several Synechococcus species contain DVR homologues. Therefore, it has been hypothesized that many other cyanobacteria producing monovinyl chlorophyll should contain a vinyl reductase that is unrelated to the higher plant DVR. To identify the cyanobacterial gene that is responsible for monovinyl chlorophyll synthesis, we developed a bioinformatics tool, correlation coefficient calculation tool, which calculates the correlation coefficient between the distributions of a certain phenotype and genes among a group of organisms. The program indicated that the distribution of a gene encoding a putative dehydrogenase protein is best correlated with the distribution of the DVR-less cyanobacteria. We subsequently knocked out the corresponding gene ( Slr1923) in Synechocystis sp. PCC6803 and characterized the mutant. The knock-out mutant lost its ability to synthesize monovinyl chlorophyll and accumulated 3,8-divinyl chlorophyll instead. We concluded that Slr1923 encodes the vinyl reductase or a subunit essential for monovinyl chlorophyll synthesis. The function and evolution of 8-vinyl reductase genes are discussed.