Lee Jung C, Gutell Robin R, Russell Rick
The Institute for Cellular and Molecular Biology, The University of Texas at Austin, 1 University Station A4800, Austin, TX 78712-0159, USA.
J Mol Biol. 2006 Jul 28;360(5):978-88. doi: 10.1016/j.jmb.2006.05.066. Epub 2006 Jun 16.
Analysis of aligned RNA sequences and high-resolution crystal structures has revealed a new RNA structural element, termed the UAA/GAN motif. Found in internal loops of the 23 S rRNA, as well as in RNase P RNA and group I and II introns, this six-nucleotide motif adopts a distinctive local structure that includes two base-pairs with non-canonical conformations and three conserved adenine bases, which form a cross-strand AAA stack in the minor groove. Most importantly, the motif invariably forms long-range tertiary contacts, as the AAA stack typically forms A-minor interactions and the flipped-out N nucleotide forms additional contacts that are specific to the structural context of each loop. The widespread presence of this motif and its propensity to form long-range contacts suggest that it plays a critical role in defining the architectures of structured RNAs.
对比对后的RNA序列和高分辨率晶体结构的分析揭示了一种新的RNA结构元件,称为UAA/GAN基序。该六核苷酸基序存在于23 S rRNA的内环以及核糖核酸酶P RNA、I类和II类内含子中,其采用独特的局部结构,包括两个具有非经典构象的碱基对和三个保守的腺嘌呤碱基,它们在小沟中形成跨链AAA堆积。最重要的是,该基序总是形成长程三级相互作用,因为AAA堆积通常形成A- minor相互作用,而翻转出的N核苷酸形成特定于每个环结构背景的额外相互作用。该基序的广泛存在及其形成长程相互作用的倾向表明,它在确定结构化RNA的结构中起着关键作用。