Interaction of monomolecular G4-DNA nanowires with TMPyP: evidence for intercalation.

摘要: Interaction of meso-tetrakis(4-N-methylpyridyl)porphyrin (TMPyP) with G4-wires composed approximately 1000 stacked tetrads (Kotlyar, A. B., Borovok, N., Molotsky, T., Cohen, H., Shapir, E., and Porath, D. (2005) Long monomolecular G4-DNA nanowires, Adv. Mater. 17, 1901-1905) was studied. These wires exist in either K (Na)-free or forms contrast to short telomeric G-quadruplexes, which are stable only the presence monovalent cations. We showed that a complex between K-free porphyrin is formed at TMPyP tetrad molar ratio 0.5. A 19 nm shift hypochromicity 58% absorption spectrum, induced CD porphyrin, efficient energy transfer suggest an intercalative mechanism binding. The form interacts much weaker than wires. Binding characterized by small (3 nm) Soret band, weak positive region, absence G-bases porphyrin. parameters reflect nonintercalative binding ions positioned center space adjacent limit access other organic molecules this thus enabling modes ligand G-quadruplex DNAs.