Guanines are a quartet's best friend: impact of base substitutions on the kinetics and stability of tetramolecular quadruplexes.

ABSTRACT: Parallel tetramolecular quadruplexes may be formed with short oligodeoxynucleotides bearing a block of three or more guanines. We analyze the properties of sequence variants of parallel quadruplexes in which each guanine of the central block was systematically substituted with a different base. Twelve types of substitutions were assessed in more than 100 different sequences. We conducted a comparative kinetic analysis of all tetramers. Electrospray mass spectrometry was used to count the number of inner cations, which is an indicator of the number of effective tetrads. In general, the presence of a single substitution has a strong deleterious impact on quadruplex stability, resulting in reduced quadruplex lifetime/thermal stability and in decreased association rate constants. We demonstrat

SUBMITTER: Gros J 

PROVIDER: S-EPMC1888817 | biostudies-literature | 2007

REPOSITORIES: biostudies-literature