Natural Selection and Structural Polymorphism of RNA 3D Structures Involving GNRA Loops and Their Receptor Motifs

Application of RNA 3D structures to RNA nanotechnology has attracted considerable attention (Guo 2010) because RNAs with defined 3D structures can be employed as platforms to generate RNA catalysts (ribozymes) (Fujita et al. 2010), RNA receptors (aptamers) (Shiohara et al. 2009), RNA gene-regulatory devices (Liang et al. 2011), self-assembling RNA nanostructures (Jaeger and Chworos 2006; Severcan et al. 2010), and multifunctional RNA nanomedicines (Guo et al. 2010; Afonin et al. 2011; Shu et al. 2011).