Rex in Clostridium kluyveri is a global redox-sensing transcriptional regulator
Rex in Clostridium kluyveri is a global redox-sensing transcriptional regulator
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克氏梭菌中的 Rex 是一种全局氧化还原感应转录调节因子
DOI：
10.1016/j.jbiotec.2016.06.024
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发表时间：
2016-09-10
影响因子：
4.1
通讯作者：
Wang, Shuning
中科院分区：
文献类型：
--
作者：
Hu, Liejie;Huang, Haiyan;Wang, Shuning
克鲁维氏梭菌在将乙醇和乙酸酯发酵为丁酸盐、己酸酯和H-2方面是独一无二的。编码丁酸产生酶的基因，包括电子分叉的丁酰辅酶A脱氢酶/电子转移黄素蛋白复合体和依赖NADH的还原铁还蛋白：NADP(+)氧化还原酶形成一个簇，在这个簇之前有一个基因被注释为转录调节因子Rex。Northern印迹和RT-PCR实验表明，该基因簇形成了一个大的转录单位，其中可能包括几个小的转录单位。推导出的Rex蛋白含有一个带翼的螺旋DNA结合域和一个可能与NAD(H)相互作用的Rossmann折叠。生物信息学分析表明，Rex可以结合许多基因的启动子区域，这些基因参与了碳和能量代谢，包括NADH氧化、产氢、ATP合成、丁酸形成和琥珀酸代谢。Rex可以调节编码某些转录调节因子和转运蛋白的基因的转录。凝胶迁移率漂移和等温滴定量热法分析表明，Rex与靶基因的启动子区域特异性地形成蛋白质-DNA复合体，该复合体可被NADH抑制，但可被过量的NAD(+)恢复。这些结果表明，Rex在克鲁维氏梭菌的碳和能量代谢中起着关键作用，它作为一个全球转录调节因子响应细胞内的NADHINAD‘比率。(C)2016爱思唯尔B.V.保留所有权利。
Clostridium kluyveri is unique in fermenting ethanol and acetate to butyrate, caproate, and H-2. The genes encoding butyrate-producing enzymes, including electron-bifurcating butyryl-CoA dehydrogenase/electron transfer flavoprotein complex and NADH-dependent reduced ferredoxin:NADP(+) oxidoreductase, form a cluster, which is preceded by a gene annotated as the transcriptional regulator Rex. Northern blotting and RT-PCR experiments indicated that the gene cluster forms a large transcriptional unit that possibly includes several small transcriptional units. The deduced Rex protein contains a winged helix DNA-binding domain and a Rossmann fold potentially interacting with NAD(H). Bioinformatics analysis revealed that Rex can bind the promoter regions of numerous genes, which are involved in carbon and energy metabolism, including NADH oxidation, hydrogen production, ATP synthesis, butyrate formation, and succinate metabolism. Rex may regulate the transcription of genes encoding certain transcriptional regulators and transporters. Electrophoretic mobility shift and isothermal titration calorimetry assays revealed that Rex specifically formed protein-DNA complexes with the promoter regions of target genes, which could be inhibited by NADH but restored by an excess amount of NAD(+). These results suggest that Rex plays a key role in the carbon and energy metabolism of C. kluyveri as a global transcriptional regulator in response to the cellular NADHINAD' ratio. (C) 2016 Elsevier B.V. All rights reserved.