Characterization of a lipophilic plasmid DNA condensate formed with a cationic peptide fatty acid conjugate.
Characterization of a lipophilic plasmid DNA condensate formed with a cationic peptide fatty acid conjugate.
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DOI：
10.1021/bm200127u
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发表时间：
2011-03
影响因子：
6.2
通讯作者：
T. T. Do-T.;Vicky J. Tang;J. Aguilera;C. Perry;J. Milligan
中科院分区：
文献类型：
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作者：
T. T. Do-T.;Vicky J. Tang;J. Aguilera;C. Perry;J. Milligan
在阳离子配体的存在下，DNA分子可以聚集成更大的颗粒，这一过程被称为缩合。DNA凝聚物是在自然发生的结构如噬菌体头和染色质中发现的致密堆积的模型。它们在DNA转染中有广泛的应用，也为研究电离辐射对DNA的直接损伤提供了方便的模型。此外，阳离子肽与脂肪酸的偶联物由于其简单的合成，可能代表了这些区域的一类有吸引力的配体。当质粒pUC18作为DNA靶标，n -己丙基-五精氨酸酰胺（Cap-R(5)- nh2）作为配体时，通过静态和动态光散射、沉淀、染料去除、圆二色性、纳米颗粒跟踪和原子力显微镜对所得到的混合物的物理性质进行了表征。用溶剂萃取法测定了它们的化学性质，并对其抗羟基自由基攻击和核酸酶酶切进行了研究。用Cap-R(5)-NH(2)配体对质粒进行滴定，在化学和物理性质上产生了明显的变化，这与100-2000 nm尺寸范围内凝聚DNA颗粒的形成有关。在配体的n端上的己丙基产生了大量的从水到氯仿的冷凝物的分配，以及它与中性洗涤剂Pluronic F-127的结合。物理和化学数据都与配体对质粒的凝聚一致，其中在配体中存在的己基赋予了凝聚物广泛的亲脂性。
In the presence of cationic ligands, DNA molecules can become aggregated into larger particles in a process known as condensation. DNA condensates are of interest as models for the dense packing found in naturally occurring structures such as phage heads and chromatin. They have found extensive application in DNA transfection and also provide convenient models with which to study DNA damage by the direct effect of ionizing radiation. Further, conjugates of cationic peptides with fatty acids may represent a class of attractive ligands for these areas because of their simple synthesis. When plasmid pUC18 is used as the DNA target and N-caproyl-penta-arginine amide (Cap-R(5)-NH(2)) is used as the ligand, the physical properties of the resulting mixtures were characterized using static and dynamic light scattering, sedimentation, dye exclusion, circular dichroism, nanoparticle tracking, and atomic force microscopy. Their chemical properties were assayed using solvent extraction and protection against hydroxyl radical attack and nuclease digestion. Titration of the plasmid with the Cap-R(5)-NH(2) ligand produced sharply defined changes in both chemical and physical properties, which was associated with the formation of condensed DNA particles in the 100-2000 nm size range. The caproyl group at the ligand's N-terminus produced a large increase in the partitioning of the resulting condensate from water into chloroform and in its binding to the neutral detergent Pluronic F-127. Both the physical and chemical data were all consistent with condensation of the plasmid by the ligand where the presence in the ligand of the caproyl group conferred an extensive lipophilic character upon the condensate.