Kielkopf C L, White S, Szewczyk J W, Turner J M, Baird E E, Dervan P B, Rees D C
Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA.
Science. 1998 Oct 2;282(5386):111-5. doi: 10.1126/science.282.5386.111.
Polyamide dimers containing three types of aromatic rings-pyrrole, imidazole, and hydroxypyrrole-afford a small-molecule recognition code that discriminates among all four Watson-Crick base pairs in the minor groove. The crystal structure of a specific polyamide dimer-DNA complex establishes the structural basis for distinguishing T.A from A.T base pairs. Specificity for the T.A base pair is achieved by means of distinct hydrogen bonds between pairs of substituted pyrroles on the ligand and the O2 of thymine and N3 of adenine. In addition, shape-selective recognition of an asymmetric cleft between the thymine-O2 and the adenine-C2 was observed. Although hitherto similarities among the base pairs in the minor groove have been emphasized, the structure illustrates differences that allow specific minor groove recognition.
含有三种芳环（吡咯、咪唑和羟基吡咯）的聚酰胺二聚体提供了一种小分子识别密码，可在小沟中区分所有四种沃森-克里克碱基对。特定聚酰胺二聚体与DNA复合物的晶体结构为区分T·A和A·T碱基对奠定了结构基础。对T·A碱基对的特异性是通过配体上取代吡咯对与胸腺嘧啶的O2和腺嘌呤的N3之间独特的氢键实现的。此外，还观察到对胸腺嘧啶-O2和腺嘌呤-C2之间不对称裂缝的形状选择性识别。尽管迄今为止一直强调小沟中碱基对之间的相似性，但该结构说明了允许特异性小沟识别的差异。
