Koyfman Alexey Y, Magonov Sergei N, Reich Norbert O
Department of Chemistry and Biochemistry, Biomolecular Science and Engineering Program, University of California - Santa Barbara, Santa Barbara, California 93106-9510, USA.
Langmuir. 2009 Jan 20;25(2):1091-6. doi: 10.1021/la801306j.
We describe the self-assembly of multilayer hexagonal DNA arrays through highly regular interlayer packing. Slow cooling of a mixture of three single-stranded DNA sequences with various Mg2+ concentrations leads to the self-assembly of diverse multilayer architectures. The self-assembled aggregates were deposited onto mica surfaces and examined with atomic force microscopy. The size of the two-dimensional arrays and subsequent stacking to form multilayer structures are highly dependent on Mg2+ concentration. DNA bilayers and multilayers of defined shape are favored in 2-5 mM Mg2+ with an average lateral size of 700 nm. Arrays are much larger (up to 20 microm across) in 10-15 mM Mg2+, although multiple layers still make up 20-60% of the observed structures. Domains within single layer architectures were identified using Moiré pattern analysis. Distinct structural phases within the multilayer assemblies include two layers translated by 17.5 nm and interlayer rotations of 20 degrees and 30 degrees. Three layer assemblies have cubic close packing and taller multilayer architectures of 2D DNA sheets were also identified.
我们描述了通过高度规则的层间堆积实现多层六边形DNA阵列的自组装。将具有不同Mg2+浓度的三种单链DNA序列的混合物缓慢冷却，会导致多种多层结构的自组装。将自组装聚集体沉积在云母表面，并用原子力显微镜进行检测。二维阵列的尺寸以及随后堆叠形成多层结构高度依赖于Mg2+浓度。在2-5 mM Mg2+中有利于形成特定形状的DNA双层和多层结构，平均横向尺寸为700 nm。在10-15 mM Mg2+中，阵列要大得多（直径可达20微米），尽管多层结构仍占观察到的结构的20-60%。使用莫尔条纹图案分析确定了单层结构内的区域。多层组件内不同的结构相包括两层平移17.5 nm以及层间旋转20度和30度。还确定了三层组件具有立方密堆积以及更高的二维DNA片层多层结构。
