Study on the interaction between nonionic sugar-based surfactant and DNA

The interaction of DNA with alkyl polyglucoside of different lengths was investigated by dynamic surface tension measurement, binding isotherm, UV spectra and fluorescence probe method. It was found that the binding of APG on DNA chain could be divided into two stages. At the first stage, multiglucoside interacted with DNA via its multi hydroxyl head group and formed with DNA a kinetic stable complex; at the second stage, monoglucoside due to its small head and hence less steric hindrance formed a thermal stable complex with DNA. Binding isotherms obtained by monoglucoside and DNA showed that binding of APG on DNA chain was a non-cooperative process, demonstrating the hydrogen bonding nature of the binding process. This also supports the model that APG micelle is surrounded by part of DNA chain. UV adsorption results showed the importance of hydrophobic effect in the interaction between DNA and APG. With ethidium bromide (EB) as probe, it was found by fluorescence spectra that DNA conformation was more compacted as the alkyl chain of APG increased. However, even C ₁₂APG could only partially compact DNA. Compared with the fact that CTAB could compact DNA into discrete globules, it was assumed that electrostatic effect was dominant in the interaction between DNA and surfactant.