The fluorescent base analogue 2-aminopurine is a sensitive probe for local dynamics of DNA. Its fluorescence is quenched by interaction with the neighboring bases, but the underlying mechanisms are still under investigation. We studied 2-aminopurine fluorescence in dinucleotides with each of the natural bases. Consistently, two of the four fluorescence-decay components depend strongly on temperature. Our results indicate that these components are due to the excited-state dynamics of a single conformational state. We propose a variation of the gating model in which transient unstacking occurs in the excited state.
- ultrafast transient-absorption
- time-resolved fluorescence
Somsen, O. J. G., Keukens, L., de Keijzer, M. N., van Hoek, A., & van Amerongen, H. (2005). Structural heterogeneity in DNA : Temperature dependence of 2-aminopurine fluorescence in dinucleotides. ChemPhysChem, 6(8), 1622-1627. https://doi.org/10.1002/cphc.200400648