DNA Binding to Zwitterionic Model Membranes
DNA Binding to Zwitterionic Model Membranes
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DOI：
10.1021/la9036327
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发表时间：
2010-04-06
期刊：
影响因子：
3.9
通讯作者：
Nylander, Tommy
中科院分区：
文献类型：
--
作者：
Ainalem, Marie-Louise;Kristen, Nora;Nylander, Tommy
这项研究表明，DNA（线性化质粒，4331碱基对和鲑鱼精子，2000碱基对，分别）吸附到模型膜的两性离子液晶磷脂双分子层的溶液中含有二价Ca（2+）的比例，并在溶液中含有单价Na（+）。DNA和表面支持的模型膜之间的相互作用，随后在原位使用零椭圆偏振，石英晶体微天平与耗散，以及中子反射。在Na（+）存在的情况下（在没有多价离子的情况下），DNA在吸附时采用延伸的卷曲构象。吸附层中的溶剂含量高，DNA位于膜的顶部。在二价Ca（2+）存在下。DNA吸附的驱动力是静电力，并且吸附的DNA膜不像在含Na（+）的溶液中那样稀。以囊泡为模型膜系统，用Cryo-TEM和SANS进一步研究了本体溶液中的相互作用。DNA吸附不能确定在Na（+）的存在下，使用SANS，但cryo-TEM表明相邻的单层囊泡之间的DNA的存在。在Ca（2+）存在下。DNA诱导多层囊泡的形成，其中DNA嵌入层泡。可能的静电和疏水机制的DNA在含有一价盐的溶液中的吸附进行了讨论，并在二价盐的观察相比。
This study shows that DNA (linearized plasmid, 4331 base pairs and salmon sperm, 2000 base pairs, respectively) adsorbs to model membranes of zwitterionic liquid crystalline phospholipid bilayers in solutions containing divalent Ca(2+) rations, and also in solutions containing monovalent Na(+). The interaction between DNA and surface-supported model membranes was followed in situ using null ellipsometry, quartz crystal microbalance with dissipation, as well as neutron reflectometry. In the presence of Na(+) (in the absence Of multivalent ions), DNA adopts an extended coil conformation upon adsorption. The solvent content in the adsorbed layer is high, and DNA is positioned on top of the membrane. In the presence of divalent Ca(2+). the driving force for the adsorption of DNA is electrostatic, and the adsorbed DNA film is not as dilute its in a solution containing Na(+). Cryo-TEM and SANS were further used to investigate the interaction in bulk solution using vesicles as model membrane systems. DNA adsorption could not be identified in the presence of Na(+) using SANS, but cryo-TEM indicates the presence of DNA between neighboring unilamellar vesicles. In the presence of Ca(2+). DNA induces the formation of multilamellar vesicles in which DNA intercalates the lamellae. Possible electrostatic and hydrophobic mechanisms for the adsorption of DNA in solutions containing monovalent salt are discussed and compared to the observations in divalent salt.