Design of peptide-containing chelate metal complexes for recognition of specific base sequences in DNA

为了评价氨基酸残基在含肽螯合物与DNA立体特异性结合中的作用，采用DNA纤维ESR谱研究了铜（II）的各种氨基酸和肽络合物的结合结构，发现络合物的配位面取向可以通过适当选择肽中的氨基酸和序列来调节。丙烯酰胺凝胶电泳还发现，某些含组氨酸的肽复合物在与过氧化氢的DNA断裂反应中，对DNA碱基序列的识别与其它肽复合物不同。对各种阳离子水溶性卟啉和Schiff碱的Cu（II）配合物的结构和结合常数进行了研究，并将研究扩展到邻菲咯啉Cu（II）配合物。本文合成了各种2，9-或5-取代-1，10-邻菲咯啉，它们是合成多肽螯合配体的中间体。用DNA纤维ESR谱和噬菌体DNA与过氧化氢反应产物的琼脂糖凝胶电泳，研究了Cu（Ⅱ）配合物与DNA的相互作用。结果表明，对于在DNA上随机取向的配合物和具有更多吸电子取代基（如NO2或Cl）的配体，断裂是活跃的。有人提出，非插层物种激活过氧化氢和协调的水分子的pKa值影响的反应性。用2D-NMR研究了1，10-菲咯啉和亮氨酸与Pt（II）的混合螯合物GCGCAATTGCGC的结合结构，发现该络合物是从AT碱基对的大沟插入的。

In order to evaluate the function of amino acid residues in the stereospecific binding of peptide-containing chelate complexes on DNA,the binding structures of various amino acid and peptide complexes of Cu (II) were investigated by DNA-fiber ESR spectroscopy and it was revealed that the orientation of the coordination plane of the complexes could be regulated by an appropriate choice of the amino acid and the sequence in the peptides. It was also found by means of acrylamide gel electrophoresis that some histidine-containing peptide complexes recognize differently the DNA base sequence from other peptide complexes in the DNA scission reaction with hydrogen peroxide. The research on the structure or the binding constant for various Cu (II) complexes of cationic water soluble porphyrins and Schiff bases were also published.The investigation was further extended over the phenanthroline Cu (II) complexes. Various 2,9-or 5-substituted-1,10-phenanthroline, that are the intermediates for the combined peptide-chelate ligands, were synthesized and the function of the Cu (II) complexes in the interaction with DNA were assayd by the DNA-fiber ESR spectroscopy and by an agarose gel electrophoresis of the reaction products of phage DNA with hydrogen peroxide. It was revealed that the cleaving is active for the complexes randomly orienting on the DNA and for the ligands with more electron-withdrawing substituents such as NO2 or Cl. It was proposed that the non-intercalated species activate hydrogen peroxide and that the pKa value of the coordinated water molecules affect the reactivity. The binding structure of mixed chelate complex of 1,10-phenanthroline and leucine with Pt (II) on self-compliment oligonucleotide, GCGCAATTGCGC,was investigated by 2D-NMR and was found that this complex intercalate from the major groove at the AT base pair.