A new tool for DNA research : Slalom chromatography

回旋层析是本课题组发明的一种新的、独特的DNA大分子分级方法。与所有传统的基于平衡现象的层析模式不同，回旋层析是基于首次发现的流体动力学现象。通过本课题的研究，无论是在理论方面还是在未来的应用中，都取得了非常有益的结果。影响DNA分子大小分离的主要因素是填充物的大小、洗脱液的流速和粘度、温度。这有力地表明，DNA分子越长，层流产生的摩擦力就越强。环状DNA分子的行为与线状分子不同，其行为取决于它们的拓扑差异，即超螺旋、弛豫和单链。因此，回旋色谱不仅对DNA的大小分离非常有用，而且对DNA的物理化学研究也是非常有用的。为了扩大动态范围，人们进行了各种尝试。激流模式和弱疏水模式的结合使小分子DNA的分辨率略有提高，但对大分子的分辨率却很难提高。由于cDNA大小分级的实用性也被证明，它应该为人类基因组计划做出贡献。

Slalom chromatography is a new and unique procedure for size fractionation of large DNA molecules, which was invented by our group. In contrast to all traditional chromatographic modes that are based on equilibrium phenomena, slalom chromatography is based on a hydrodynamic phenomenon, which was found for the first time. By the present research project, extremely useful results were obtained from viewpoints of not only theoretical aspects but also future applications. Principal factors which affect size separation of DNA molecules proved to be size of packing particle, flow rate and viscosity of eluents, and temperature. This strongly suggests that the longer a DNA molecule, the more strong frictional force is generated because of laminar flow. Behavior of circular form DNA molecules was different for linear molecules and found to depend on their topological differences, that is, super coil, relaxd and single strand. Therefore, slalom chromatography seems to be very useful for not only size separation but also physicochemical studies of DNA.In order to widen the dynamic range, various attempts have been made. Resolution of smaller DNA molecules was slightly improved by the combination of slalom mode and weak hydrophobic mode, but it was difficult to improve resolution of larger molecules. Since utility of size fractionation of cDNAs was also demonstrated, it should contribute to the human genom project.