Chen J H, Seeman N C
Department of Chemistry, New York University, NY 10003.
Electrophoresis. 1991 Sep;12(9):607-11. doi: 10.1002/elps.1150120902.
Electrophoretic properties have been measured for a DNA molecule whose helix axes have the connectivity of a cube. This molecule is a topologically bonded complex of six cyclic 80-mer molecules, in which each cycle corresponds to a face of the cube. Each cyclic molecule is doubly catenated to each of its four neighbors. Substructures of this molecule include a 5-cycle structure lacking one strand, two topoisomers of 4-cycle structures and two topoisomers of 3-cycle structures. One 4-cycle structure is a cyclic belt around the cube, lacking a top and a bottom, whereas the other lacks two catenated strands, such as the top and the front. One 3-cycle structure is a linear belt of three cycles, and the other corresponds to the three cycles that surround a corner. Each of these molecules is separable from the others under appropriate gel conditions. We have measured mobilities and calculated Ferguson plots for each of these molecules on polyacrylamide gels under both native and denaturing conditions. The measurements have been made with 1.25, 2.5, and 5% crosslinking of the gels. The data show that the higher-symmetry 3-cycle and 4-cycle structures migrate more slowly than their lower-symmetry isomers, under conditions where their Ferguson plots are parallel.
已对一种DNA分子的电泳性质进行了测量，该分子的螺旋轴具有立方体的连通性。这种分子是由六个环状80聚体分子形成的拓扑键合复合物，其中每个环对应于立方体的一个面。每个环状分子与它的四个相邻分子都有双链连环。该分子的子结构包括一个缺少一条链的5环结构、4环结构的两种拓扑异构体和3环结构的两种拓扑异构体。一种4环结构是围绕立方体的环状带，缺少顶部和底部，而另一种则缺少两条连环链，如顶部和前面的链。一种3环结构是由三个环组成的线性带，另一种对应于围绕一个角的三个环。在适当的凝胶条件下，这些分子中的每一个都可以与其他分子分离。我们已经测量了这些分子在天然和变性条件下在聚丙烯酰胺凝胶上的迁移率，并计算了它们的弗格森图。测量是在凝胶交联度为1.25%、2.5%和5%的情况下进行的。数据表明，在它们的弗格森图平行的条件下，具有较高对称性的3环和4环结构的迁移速度比其对称性较低的异构体慢。
