Nucleic Acids Research, 2003, Vol. 31, No. 15 4497-4502
© 2003 Oxford University Press
Oligoamine–acridine conjugates for promotion of gap-selective DNA hydrolysis by Ce(IV)/EDTA complex
Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
*To whom correspondence should be addressed. Tel: +81 3 5452 5200; Fax: +81 3 5452 5209; Email: komiyama{at}mkomi.rcast.u-tokyo.ac.jp
Oligoamines (spermidine, dipropylenetriamine and propylenediamine) were covalently attached to acridine via a hexamethylene linker. These oligoamine–acridine conjugates were efficiently bound to gap sites in substrate DNA, and promoted the DNA hydrolysis by a homogeneous Ce(IV)/ethylenediamine-N,N,N',N'-tetraacetate (EDTA) complex at these sites. In contrast, the hydrolysis of the double-stranded portion in the DNA was little affected by these conjugates, although they were strongly bound thereto by the intercalation of their acridine moieties. As a result, the gap site was selectively and efficiently hydrolyzed by combining the Ce(IV)/EDTA complex with the oligoamine– acridine conjugate. Either the oligoamine or the acridine was only poorly active for the purpose, substantiating the essential role of cooperation between them. The promotion of gap-selective DNA hydrolysis by the conjugates has been ascribed to electrostatic stabilization of a negatively charged transition state by their positive charges.