退火时间对二维DNA晶体自组装的影响

Effect of the annealing time on the self-assembly of two-dimensional DNA crystals

DNA自组装的过程,不仅需要合适的缓冲液,还需要适当的退火时间.本文利用DNA自组装技术,以反向平行双交叉(double-crossover,DX)DNA分子瓦(DNAtile)作为建筑模块,带有互补黏性末端(sticky-ends)的分子瓦依据Watson-Crick碱基互补配对原则配对连接,成功制备出二维晶体结构.比较不同退火时间下形成的DNA分子瓦结构,采用非变性聚丙烯酰胺凝胶电泳(non-denaturing PAGE)表征.结果表明,退火时间为2.5h时形成的分子瓦的结构较稳定.等量混合此条件下形成的不同分子瓦,分别从50,37和25℃退火至室温,利用原子力显微镜(AFM)对退火后的结构进行表征,结果表明,起始退火温度为37℃时得到的DNA二维晶体较平整.

DNA self-assembly process requires not only appropriate buffer solution but also suitable annealing conditions.We have successfully assembled two-dimensional DNA crystals based on the anti-parallel double-crossover（DX） tiles by the design of sticky-ends that associate according to Watson-Crick complementarity.The DX tiles formed under different annealing conditions were characterized by non-denaturing polyacrylamide gel electrophoresis（PAGE）,and the results showed that the tiles annealed from 95℃ to room temperature during 2.5 h were more stable.DX tiles formed in this condition were mixed stoichiometrically and annealed from 50,37,and 25℃ to room temperature,respectively.After that,the structures were visualized by atomic force microscopy（AFM）.The results indicated that better two dimensional crystals could be obtained when the mixed tiles annealed from 37℃.