Livolant F
Centre de Biologie Cellulaire (CNRS), Ivry-sur-Seine, France.
J Mol Biol. 1991 Mar 5;218(1):165-81. doi: 10.1016/0022-2836(91)90882-7.
I present an electron microscopical analysis of the columnar hexagonal liquid crystalline phase of DNA. Freeze-fracture methods reveal that this phase is a lamellar structure, each layer (30 to 40 A thick) composed of DNA molecules aligned in parallel. Numerous defects can be seen in the structure, and their nature is determined. I show that they are mainly screw dislocations of both handedness. By this method it is possible to follow individual double-stranded DNA molecules in this highly packed structure. I show, moreover, that there is a local twist between DNA molecules along the screw dislocation lines and that this twist can be either right-handed or left-handed. The interest of such ultrastructural analysis is discussed in relation to the understanding of chromatin structure.
我展示了对DNA柱状六方液晶相的电子显微镜分析。冷冻断裂方法显示，该相是一种层状结构，每层（30至40埃厚）由平行排列的DNA分子组成。在结构中可以看到许多缺陷，并确定了它们的性质。我表明它们主要是两种手性的螺旋位错。通过这种方法，可以在这种高度堆积的结构中追踪单个双链DNA分子。此外，我表明沿着螺旋位错线的DNA分子之间存在局部扭曲，并且这种扭曲可以是右手或左手的。结合对染色质结构的理解讨论了这种超微结构分析的意义。
