Diversity of Cobalamin Riboswitches in the Corrinoid-Producing Organohalide Respirer Desulfitobacterium hafniense
Diversity of Cobalamin Riboswitches in the Corrinoid-Producing Organohalide Respirer Desulfitobacterium hafniense
复制标题
DOI：
10.1128/jb.00730-13
复制
发表时间：
2013-11-01
影响因子：
3.2
通讯作者：
Maillard, Julien
中科院分区：
文献类型：
--
作者：
Choudhary, Pallavi K.;Duret, Aurelie;Maillard, Julien
原核生物在污染生态位中的策略性适应涉及对其代谢的有效调节。专性厌氧和代谢多功能的Desulfitobacterium hafniense还原脱氯卤化有机化合物（所谓的有机卤化物）。一些D. hafniense菌株进行有机卤化物呼吸（OHR），这一过程需要使用椰碱作为还原脱卤酶的辅助因子，还原脱卤酶是OHR的关键酶。我们在这里报道了可能调节D. hafniense类钴胺素代谢的钴胺素核开关的多样性。对现有D. hafniense基因组的分析表明，在其产物主要参与类钴胺生物合成和运输的基因上游存在18个钴胺素核开关。为了深入了解它们的功能，Mfold预测了其中三个RNA元件的二级结构，并通过在线探针进行了分析。这些RNA元件在其结构元件上都表现出多样性，并且对腺苷钴胺素表现出不同的亲和力，这可能与它们在调节类椰素代谢中的作用有关。此外，腺苷钴胺诱导下游基因的RNA合成在体内受到抑制，这表明D. hafniense菌株TCE1的corcoroid转运体和生物合成酶在转录水平上受到调控。综上所述，在有机卤化物污染的环境中，核糖体开关介导的corcoroid复杂代谢调节可能对监测其细胞内corcoroid水平以及与corcoroid -营养不良OHR细菌共存具有重要意义。
The strategic adaptation of prokaryotes in polluted niches involves the efficient regulation of their metabolism. The obligate anaerobe and metabolically versatile Desulfitobacterium hafniense reductively dechlorinates halogenated organic compounds (so-called organohalides). Some D. hafniense strains carry out organohalide respiration (OHR), a process which requires the use of corrinoid as a cofactor in reductive dehalogenases, the key enzymes in OHR. We report here the diversity of the cobalamin riboswitches that possibly regulate the corrinoid metabolism for D. hafniense. The analysis of available D. hafniense genomes indicates the presence of 18 cobalamin riboswitches located upstream of genes whose products are mainly involved in corrinoid biosynthesis and transport. To obtain insight into their function, the secondary structures of three of these RNA elements were predicted by Mfold, as well as analyzed by in-line probing. These RNA elements both display diversity in their structural elements and exhibit various affinities toward adenosylcobalamin that possibly relates to their role in the regulation of corrinoid metabolism. Furthermore, adenosylcobalamin-induced in vivo repression of RNA synthesis of the downstream located genes indicates that the corrinoid transporters and biosynthetic enzymes in D. hafniense strain TCE1 are regulated at the transcriptional level. Taken together, the riboswitch-mediated regulation of the complex corrinoid metabolism in D. hafniense could be of crucial significance in environments polluted with organohalides both to monitor their intracellular corrinoid level and to coexist with corrinoid-auxotroph OHR bacteria.