乙醇与三氯六氨络合钴协同作用导致的DNA凝聚

Synergetic DNA condensation induced by ethanol and hexammine cobalt

利用原子力显微镜技术(AFM),系统地研究了由乙醇与多价离子(hexammine cobalt(Ⅲ)[Co(NH3)36+])协同作用导致的λ-DNA凝聚现象.单独测得3价Co(NH3)36+的临界凝聚浓度大约是10μmol·L-1,乙醇的临界凝聚体积分数大约是15%.若3价离子[Co(NH3)36+]的浓度大于400μmol·L-1时,可以观察到DNA的解凝聚现象.在DNA溶液中同时加入乙醇(体积分数12%)与Co(NH3)36+(8μmol.L-1),当其浓度各低于其临界值,也可观察到凝聚现象,说明乙醇与Co(NH3)36+对DNA的凝聚有协同作用,而且在协同作用下,可以观察到典型的圆环结构(toroids).利用电荷逆转与离子释放机制分析了观察到的解凝聚现象.

The condensed morphologies of λ-DNA condensation induced by ethanol and hexammine cobalt(Ⅲ)[Co(NH3)3+6] were observed using atomic force microscopy(AFM).The critical condensation concentration for hexammine cobalt(Ⅲ) is found to be about 10 μmol·L-1.The critical concentration for ethanol is about 15%.When the concentration is larger than 400 μmol·L-1,DNA decondensation phenomenon is seen.By adding mixtures of 12% ethanol and 8 μmol·L-1 hexammine cobalt(Ⅲ) to DNA solution,DNA condensation patterns are observed even when the concentrations of the two condensation agents is lower than their critical values.Typical toroids are found induced collaboratively by ethanol and hexammine cobalt(Ⅲ).The decondensation phenomenon was analyzed by charge reversion and ion releasing mechanism.