Gallo Sofia, Oberhuber Michael, Sigel Roland K O, Kräutler Bernhard
Institute of Inorganic Chemistry, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
Chembiochem. 2008 Jun 16;9(9):1408-14. doi: 10.1002/cbic.200800099.
Riboswitches are regulatory elements in the 5'-untranslated region (5'-UTR) of bacterial mRNAs that bind certain metabolites with high specificity and affinity. The 202 nucleotide (nt)-long btuB riboswitch RNA of E. coli interacts specifically with coenzyme B12 and its derivatives thereby leading to changes in the RNA structure and hence to an altered expression of the downstream btuB gene. We report the investigations of the rearrangement of the three-dimensional structure of the btuB riboswitch upon binding to four different B12 derivatives: coenzyme B12, vitamin B12, adenosyl factor A and adenosyl-cobinamide. In-line probing experiments have shown that the corrin ring plays the crucial role in switching the three-dimensional riboswitch structure. Instead, the apical ligands influence only the binding affinity of the B12 derivative to the btuB riboswitch.
核糖开关是细菌mRNA 5'-非翻译区（5'-UTR）中的调控元件，能以高特异性和亲和力结合某些代谢物。大肠杆菌中202个核苷酸（nt）长的btuB核糖开关RNA与辅酶B12及其衍生物特异性相互作用，从而导致RNA结构发生变化，进而改变下游btuB基因的表达。我们报告了关于btuB核糖开关与四种不同的B12衍生物（辅酶B12、维生素B12、腺苷因子A和腺苷钴胺素）结合后三维结构重排的研究。在线探测实验表明，咕啉环在切换核糖开关三维结构中起关键作用。相反，顶端配体仅影响B12衍生物与btuB核糖开关的结合亲和力。
