The formation pathway of tetramolecular G-quadruplexes.

ABSTRACT: Oligonucleotides containing guanosine stretches associate into tetrameric structures stabilized by monovalent ions. In order to describe the sequence of reactions leading to association of four identical strands, we measured by NMR the formation and dissociation rates of (TGnT)4 quadruplexes (n = 3-6), their dissociation constants and the reaction orders for quadruplex formation. The quadruplex formation rates increase with the salt concentration but weakly depend on the nature (K+, Na+ or Li+) of the counter ions. The activation energies for quadruplex formation are negative. The quadruplex lifetimes strongly increase with the G-tract length and are much more longer in K+ solution than in Na+ or Li+ solutions. The reaction order for quadruplex formation is 3 in 0.125 M KCl and 4 in LiCl s

SUBMITTER: Bardin C 

PROVIDER: S-EPMC2241855 | biostudies-literature | 2008 Feb

REPOSITORIES: biostudies-literature