2004). The purine-sensing riboswitches form tuning-fork-like architectures, in which the prongs are held in parallel through hairpin loop interactions, and the internal bubble zippers up to form the ...

This image illustrates the chemical structures of the five main nucleobases found in DNA and RNA. The pyrimidines, thymine (DNA), uracil (RNA), and cytosine are shown on top while the purines, adenine ...

The purine structure consists of a pyrimidine ring (positions 1 to 6) fused to an imidazole ring (positions 7 to 9). Adenine and guanine, the two most common purines in DNA and RNA, share this core ...