Livolant F, Levelut A M, Doucet J, Benoit J P
Centre de Biologie Cellulaire (CNRS), Ivry-sur-Seine, France.
Nature. 1989 Jun 29;339(6227):724-6. doi: 10.1038/339724a0.
The DNA molecule is extremely compacted in bacteria, in cell nuclei, sperm heads and virus capsids. These interactions between DNA molecules are important to our understanding of chromatin condensation. DNA forms multiple liquid-crystalline phases whose nature depends on the polymer concentration, and it has been suggested that the highly concentrated phase of 50-nm DNA molecules is two-dimensionally ordered and smectic-like. We rule out this smectic hypothesis and demonstrate by polarizing microscopy, electron microscopy and X-ray diffraction that this phase is characterized by a columnar longitudinal order and a hexagonal lateral order, with intermolecular distances ranging from 2.8 to 4.0 nm depending on the DNA concentration.
在细菌、细胞核、精子头部和病毒衣壳中，DNA分子极度压缩。DNA分子之间的这些相互作用对于我们理解染色质凝聚很重要。DNA形成多个液晶相，其性质取决于聚合物浓度，并且有人提出50纳米DNA分子的高浓度相是二维有序且类似近晶相的。我们排除了这种近晶相假说，并通过偏光显微镜、电子显微镜和X射线衍射证明，这个相的特征是柱状纵向有序和六方横向有序，分子间距离根据DNA浓度在2.8至4.0纳米之间变化。
