Recognition of nine base pairs in the minor groove of DNA by a tripyrrole peptide-Hoechst conjugate.
Recognition of nine base pairs in the minor groove of DNA by a tripyrrole peptide-Hoechst conjugate.
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DOI：
10.1021/ja003095d
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发表时间：
2001-02
影响因子：
15
通讯作者：
A. Satz;T. C. Bruice
中科院分区：
文献类型：
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作者：
A. Satz;T. C. Bruice
设计了一种三吡咯肽-Hoechst偶联物（FPH-1），其在亚纳摩尔浓度下识别9个富含dA/dT碱基对A/T的dsDNA序列，并以接近扩散控制的速率复合其靶标以形成荧光产物。荧光滴定表明配合物的化学计量比为（FPH-1）（2）：dsDNA。荧光分光光度滴定法也被用来确定35种不同的寡聚双链体的两个FPH-1分子与dsDNA络合的平衡常数（K（1）K（2））的乘积。发现FPH-1结合位点的单碱基对错配导致K（1）K（2）显著降低18- 2300倍。热变性实验提供了类似的结果。提出了支持（FPH-1）（2）：dsDNA小沟复合物的结构的论点，其涉及两个FPH-1分子以略微交错、并排和反平行的排列，使得一个FPH-1分子的双苯并咪唑部分与第二个FPH-1分子的三吡咯部分相邻。
A tripyrrole peptide-Hoechst conjugate (FPH-1) has been designed which recognizes nine dA/dT base pair A/T rich dsDNA sequences at subnanomolar concentrations and complexes its targets at near diffusion controlled rates to form a fluorescent product. Spectrofluorometric titrations show the stoichiometry of the complex to be (FPH-1)(2):dsDNA. Spectrofluorometric titrations were also employed to determine the product of the equilibrium constant for complexation (K(1)K(2)) of dsDNA by two FPH-1 molecules for 35 different oligomeric duplexes. Single base pair mismatches in the FPH-1 binding site were found to cause significant decreases in K(1)K(2) of 18- to 2300-fold. Thermal denaturation experiments provided similar results. Arguments are presented which favor the structure of the (FPH-1)(2):dsDNA minor groove complex to involve the two FPH-1 molecules in a slightly staggered, side-by-side, and antiparallel arrangement such that the bis-benzimidazole moiety of one FPH-1 molecule lies adjacent to the tripyrrole moiety of the second FPH-1 molecule.