Adenine riboswitches and gene activation by disruption of a transcription terminator
Adenine riboswitches and gene activation by disruption of a transcription terminator
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DOI：
10.1038/nsmb710
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发表时间：
2004-01-01
影响因子：
16.8
通讯作者：
Breaker, RR
中科院分区：
文献类型：
--
作者：
Mandal, M;Breaker, RR
最近发现了一类识别鸟嘌呤并区分其他嘌呤类似物的核糖开关。携带鸟嘌呤核糖开关的共有序列和结构特征的RNA位于许多原核基因的5'非翻译区（UTR）中，在那里它们控制参与嘌呤补救和生物合成的蛋白质的表达。我们报告说，这三个代表核糖开关类结合腺嘌呤的表观解离常数（表观Kd）的值是几个数量级低于结合鸟嘌呤。由于腺嘌呤的优先选择是由于单核苷酸取代，RNA很可能通过形成沃森-克里克碱基对来识别其配体。此外，与枯草芽孢杆菌的ydhL基因相关的腺嘌呤核糖开关起遗传“开启”开关的作用，其中腺嘌呤结合引起结构重排，其排除内在转录终止子茎的形成。
A class of riboswitches that recognizes guanine and discriminates against other purine analogs was recently identified. RNAs that carry the consensus sequence and structural features of guanine riboswitches are located in the 5' untranslated region (UTR) of numerous prokaryotic genes, where they control the expression of proteins involved in purine salvage and biosynthesis. We report that three representatives of this riboswitch class bind adenine with values for apparent dissociation constant (apparent K-d) that are several orders of magnitude lower than those for binding guanine. Because preference for adenine is attributable to a single nucleotide substitution, the RNA most likely recognizes its ligand by forming a Watson-Crick base pair. In addition, the adenine riboswitch associated with the ydhL gene of Bacillus subtilis functions as a genetic 'on' switch, wherein adenine binding causes a structural rearrangement that precludes formation of an intrinsic transcription terminator stem.