Effect of 6-thioguanine on the stability of duplex DNA.

ABSTRACT: The incorporation of 6-thioguanine (S6G) into DNA is a prerequisite for its cytotoxic action, but duplex structure is not significantly perturbed by the presence of the lesion [J. Bohon and C. R. de los Santos (2003) Nucleic Acids Res., 31, 1331-1338]. It is therefore possible that the mechanism of cytotoxicity relies on a loss of stability rather than a pathway involving direct structural recognition. The research described here focuses on the changes in thermodynamic properties of duplex DNA owing to the introduction of S6G as well as the kinetic properties of base pairs involving S6G. Replacement of a guanine in a G*C pair by S6G results in approximately 1 kcal/mol less favorable Gibbs free energy of duplex formation at 37 degrees C. S6G*T and G*T mismatch-containing duplexes have almos

SUBMITTER: Bohon J 

PROVIDER: S-EPMC1131932 | biostudies-literature | 2005

REPOSITORIES: biostudies-literature