indicated that the structure of the complex
between ssDNA-aptamer and adenosine in solution consists of two
small Watson–Crick helices and two G-quartets. Four guanosines
assembled via hydrogen bonds and two G-quartets stack on each
other to form a stable structure in the presence of metal cations.
Aptamer catches two adenosine molecules between the top Gquartet
and the two short stems form a pocket [12].