title: The octaplex structure of d(GCGAGAGC) with I-motif of guanine quartet, controlled by potassium concentration.
abstract: Crystal structures of DNA octamer with the sequence d(GCGAGAGC) have been determined by X-ray analyses to investigate the specific DNA structural motifs that are useful for designing various functional DNA molecules. The octamers are assembled to form an octaplex with G-quartets and water-mediated A-quartets. At relatively high potassium concentration, however, the octaplex is split into two quadruplexes, each of which contains two G-duets. The two crystal forms suggest a dynamic formation of an octaplex from two quadruplexes in solution.
mesh_terms: D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry*; D006147:Guanine / Q000737:chemistry*; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D011188:Potassium / Q000737:chemistry*
chemical_list: D006147:Guanine; D004247:DNA; D011188:Potassium