Drew H R, Travers A A
Cell. 1984 Jun;37(2):491-502. doi: 10.1016/0092-8674(84)90379-9.
X-ray studies have established that the structure of a right-handed, Watson-Crick double helix can change from place to place along its length as a function of base sequence. The base pairs transmit deformations out to the phosphate backbone, where they can then be recognized by proteins and other DNA-binding reagents. Here we have examined at single-bond resolution the interactions of three commonly used nucleases (DNAase I, DNAase II, and copper-phenanthroline) with a DNA of natural origin, the 160 bp tyrT promoter. All three of these reagents seem sensitive to DNA backbone geometry rather than base sequence per se. Their sequence-dependent patterns of cleavage provide evidence for structural polymorphism of several sorts: global variation in helix groove width, global variation in radial asymmetry, and local variation in phosphate accessibility. These findings explain how sequence zones of a certain base composition, or purine-pyrimidine asymmetry, can influence the recognition of DNA by protein molecules.
X射线研究表明，右手螺旋的沃森-克里克双螺旋结构会随着碱基序列的变化而沿其长度发生改变。碱基对将变形传递到磷酸骨架上，蛋白质和其他DNA结合试剂可以识别这些变形。在这里，我们以单键分辨率研究了三种常用核酸酶（DNA酶I、DNA酶II和铜-菲咯啉）与天然来源的DNA（160bp tyrT启动子）之间的相互作用。这三种试剂似乎都对DNA骨架几何结构敏感，而非碱基序列本身。它们依赖序列的切割模式为几种结构多态性提供了证据：螺旋沟宽度的整体变化、径向不对称性的整体变化以及磷酸基团可及性的局部变化。这些发现解释了特定碱基组成或嘌呤-嘧啶不对称性的序列区域如何影响蛋白质分子对DNA的识别。
