Characterization of FerC, a MarR-type transcriptional regulator, involved in transcriptional regulation of the ferulate catabolic operon in Sphingobium sp strain SYK-6
Characterization of FerC, a MarR-type transcriptional regulator, involved in transcriptional regulation of the ferulate catabolic operon in Sphingobium sp strain SYK-6
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DOI：
10.1111/j.1574-6968.2012.02576.x
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发表时间：
2012-07-01
影响因子：
2.1
通讯作者：
Masai, Eiji
中科院分区：
文献类型：
--
作者：
Kasai, Daisuke;Kamimura, Naofumi;Masai, Eiji
Sphingobium sp.菌株SYK-6能够降解各种木质素衍生的芳香族化合物，包括阿魏酸盐、香草酸盐和丁香酸盐。在SYK-6细胞中，阿魏酸盐分别通过铁A编码的阿魏酰辅酶A合成酶和铁b编码的阿魏酰辅酶A水合酶/裂解酶催化的反应转化为香兰素和乙酰辅酶A。在这里，我们表征了由marr型转录调控因子FerC控制的ferBA的转录调控。铁c基因位于铁b的上游。反转录（RT -PCR）分析表明，ferBA基因形成一个操纵子。对SYK-6及其突变体细胞的定量RT-PCR分析显示，ferBA操纵子的转录受到FerC的负调控，并鉴定出阿铁酰辅酶a是一种诱导剂。ferB的转录起始位点定位在ferB起始密码子上游30个核苷酸处。纯化的his标记的FerC结合到ferCferB基因间区。该区域包含一个反向重复序列，该序列与-10序列和ferB转录起始位点的一部分重叠。添加阿魏酰辅酶a可以抑制FerC与操作序列的结合，表明FerC作为效应分子与阿魏酰辅酶a相互作用。此外，羟基肉桂酰辅酶a，包括对香豆酚酰辅酶a、咖啡酰辅酶a和樟脑酰辅酶a也起效应。
Sphingobium sp. strain SYK-6 is able to degrade various lignin-derived aromatic compounds including ferulate, vanillate, and syringate. In the SYK-6 cells, ferulate is converted to vanillin and acetyl-coenzyme A (acetyl-CoA) through the reactions catalyzed by feruloyl-CoA synthetase and feruloyl-CoA hydratase/lyase encoded by ferA and ferB, respectively. Here, we characterized the transcriptional regulation of ferBA controlled by a MarR-type transcriptional regulator, FerC. The ferC gene is located upstream of ferB. Reverse transcription (RT)-PCR analysis suggested that the ferBA genes form an operon. Quantitative RT-PCR analyses of SYK-6 and its mutant cells revealed that the transcription of the ferBA operon is negatively regulated by FerC, and feruloyl-CoA was identified as an inducer. The transcription start site of ferB was mapped at 30 nucleotides upstream from the ferB initiation codon. Purified His-tagged FerC bound to the ferCferB intergenic region. This region contains an inverted repeat sequence, which overlaps with a part of the -10 sequence and the transcriptional start site of ferB. The binding of FerC to the operator sequence was inhibited by the addition of feruloyl-CoA, indicating that FerC interacts with feruloyl-CoA as an effector molecule. Furthermore, hydroxycinnamoyl-CoAs, including p-coumaroyl-CoA, caffeoyl-CoA, and sinapoyl-CoA also acted as effector.