Beal P A, Dervan P B
Arnold and Mabel Beckman Laboratories of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena 91125.
Science. 1991 Mar 15;251(4999):1360-3. doi: 10.1126/science.2003222.
Relative orientations of the DNA strands within a purine.purine.pyrimidine triple helix have been determined by affinity cleaving. A purine-rich oligonucleotide bound in the major groove of double-helical DNA antiparallel to the Watson-Crick purine strand. Binding depended upon the concentration of multivalent cations such as spermine or Mg2+, and appeared to be relatively independent of pH. Two models with specific hydrogen-bonding patterns for base triplets (G.GC, A.AT, and T.AT) are proposed to explain the sequence specificity of binding. The two models differ in the conformation about the glycosyl bond (syn or anti) and the location of the phosphate-deoxyribose backbone in the major groove of DNA. This motif broadens the structural frameworks available as a basis for the design of sequence-specific DNA binding molecules.
通过亲和切割确定了嘌呤-嘌呤-嘧啶三螺旋内DNA链的相对方向。一条富含嘌呤的寡核苷酸结合在双螺旋DNA的大沟中，与沃森-克里克嘌呤链反向平行。结合取决于多价阳离子（如精胺或Mg2+）的浓度，并且似乎相对独立于pH值。提出了两种具有特定碱基三联体氢键模式（G.GC、A.AT和T.AT）的模型来解释结合的序列特异性。这两种模型在糖基键的构象（顺式或反式）以及磷酸-脱氧核糖骨架在DNA大沟中的位置方面有所不同。这种基序拓宽了可作为序列特异性DNA结合分子设计基础的结构框架。
