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络合物与DNA的立体特异性结合中的作用，用DNA纤维ESR波谱研究了各种氨基酸与铜(II)的多肽络合物的结合结构，发现适当选择氨基酸和多肽中的序列可以调节络合物的配位平面的取向。通过丙烯酰胺凝胶电泳法还发现，在DNA与过氧化氢的断裂反应中，一些含组氨酸的多肽复合体识别DNA碱基序列的方式与其他多肽复合体不同。对不同阳离子水溶性卟啉与席夫碱的铜(II)络合物的结构和结合常数进行了研究，并对邻菲咯啉铜(II)络合物进行了进一步的研究。合成了多种2，9-或5-取代-1，10-菲咯啉，并用DNA纤维ESR波谱和噬菌体DNA与过氧化氢反应产物的琼脂糖凝胶电泳法研究了铜(II)络合物与DNA相互作用的功能。结果表明，对于随机定位于DNA上的络合物和具有较多吸电子取代基的配体，如NO2或Cl，裂解是活跃的。认为非插层物种激活了过氧化氢，配位水分子的pKa值影响了反应活性。用2D-核磁共振方法研究了1，10-二氮杂菲、亮氨酸与铂(II)在自互补寡核苷酸GCGCAATTGCGC上的混合络合物的结合结构，发现该络合物是从AT碱基对的主槽插入的。

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.