【摘要】 活性细胞众多的遗传信息均通过ＤＮＡ链的碱基序列按一定的自身调节方式表达出各种蛋白质［１］．ＤＮＡ与各种不同性质的组分，如蛋白质、类脂及无机离子等的相互识别作用是确保细胞处于生理活性状态的重要调节机制．阳离子型表面活性剂与带相反电荷的多价离子的相互作用...更多还原

【Abstract】 The interaction between cetyltrimethylammonium bromide(CTAB) and λ DNA was studied by SEM and AFM. It is clear that λ DNA molecules exhibit discrete conformational change between the coil and globule states with the addition of cationic surfactant. When the concentration of CTAB is less than 2×10 -6 mol/L , all DNA molecules exhibit the extended coil state. Whereas, when the CTAB concentration is higher than 8 0×10 -6 mol/L , only compacted DNA molecules in the globular state are observed. To study of coil globule transition, the process of the structural change from the coilinto the globule state is observed under the spatial gradient of the CTAB concentration. The formation of aggregates from two or more globules is noticed at high concentrations of surfactant above 8 0×10 -5 mol/L. The surfactant λ DNA complex has a hydrophobic region akin to ordinary micelle.更多还原