Makino Tetsunao, Kajitani Takashi, Tanaka Makiko
Department of Engineering Science, Graduate School of Informatics and Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo, 182-8585, Japan.
Core Facility Center, Research Infrastructure Management Center, Institute of Science Tokyo, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan.
Small. 2025 Feb;21(6):e2410243. doi: 10.1002/smll.202410243. Epub 2024 Dec 23.
This paper discusses the controlled morphology of hierarchical liquid crystalline DNA assemblies. Through a process of heating and slow cooling, double-stranded DNAs (dsDNAs) having 23 complementary bases and two base overhangs (a pair of 25mer oligonucleotides) spontaneously assemble into micro-sized hexagonal platelets in a solution containing poly(ethylene glycol) (PEG) and salt. Remarkably, the addition of a shorter dsDNA with AA/TT overhangs (a pair of 18mer oligonucleotides) to a PEG-salt solution of 25mer DNA with AA/TT overhangs results in the formation of molecular tubes, each with a central blockage. In contrast, the addition of 18mer DNA with GG/CC overhangs leads to the formation of hexagonal frames from hexagonal platelets. In the assemblies, 18mer DNA is more predominant at the edges, while the central nuclei are composed of 25mer DNA. X-ray scattering measurements reveal that both molecular tubes and hexagonal frames form hexagonal columnar liquid crystalline assemblies. These self-assemblies are thought to result from depletion attraction due to PEG and end-to-end stacking between dsDNA overhangs. Differences in the melting temperatures between longer and shorter dsDNAs enable the stepwise formation of hierarchical assemblies, while variations in overhang sequences modulate the overall morphology by altering the growth direction of the assemblies.
本文讨论了分级液晶DNA组装体的可控形态。通过加热和缓慢冷却的过程，具有23个互补碱基和两个碱基突出端（一对25聚体寡核苷酸）的双链DNA（dsDNA）在含有聚乙二醇（PEG）和盐的溶液中自发组装成微米级的六角形薄片。值得注意的是，向具有AA/TT突出端的25聚体DNA的PEG-盐溶液中添加具有AA/TT突出端的较短双链DNA（一对18聚体寡核苷酸）会导致形成分子管，每个分子管都有一个中心堵塞。相反，添加具有GG/CC突出端的18聚体DNA会导致从六角形薄片形成六角形框架。在组装体中，18聚体DNA在边缘处更为突出，而中心核由25聚体DNA组成。X射线散射测量表明，分子管和六角形框架都形成了六角柱状液晶组装体。这些自组装被认为是由于PEG引起的耗尽吸引以及dsDNA突出端之间的端到端堆积所致。较长和较短双链DNA之间的解链温度差异使得能够逐步形成分级组装体，而突出端序列的变化则通过改变组装体的生长方向来调节整体形态。
