Subirana J A, Martínez A B
Nucleic Acids Res. 1976 Nov;3(11):3025-42. doi: 10.1093/nar/3.11.3025.
Model calculations are presented in order to interpret the X-ray diffraction diagrams given by chromatin gels. It is shown that by taking into account the hydration of chromatin subunits, the problem of calculating the interference function in concentrated gels is greatly simplified. In this way it is spossible to fully interpret the influence of concentration on the position and intensity of the various rings present in the X-ray diffraction patterns. The possibilities and limitations of models based on spherical symmetry are also discussed. It is concluded that each chromatin subunit most likely contains three turns of DNA in each 200 base pairs segment surrounding a central protein core. With the method presented here it is possible to test if other models of chromatin based on different kinds of evidence are compatible with the X-ray diffraction data.
为了解释染色质凝胶给出的X射线衍射图谱，进行了模型计算。结果表明，考虑到染色质亚基的水化作用，计算浓缩凝胶中干涉函数的问题大大简化。通过这种方式，可以充分解释浓度对X射线衍射图谱中各种环的位置和强度的影响。还讨论了基于球对称性的模型的可能性和局限性。得出的结论是，每个染色质亚基在围绕中心蛋白质核心的每200个碱基对片段中最有可能包含三圈DNA。使用此处介绍的方法，可以测试基于不同证据的其他染色质模型是否与X射线衍射数据兼容。
