Binding, electrochemical activation, and cleavage of DNA by cobalt(II) tetrakis-N-methylpyridyl porphyrin and its beta-pyrrole brominated derivative.
Binding, electrochemical activation, and cleavage of DNA by cobalt(II) tetrakis-N-methylpyridyl porphyrin and its beta-pyrrole brominated derivative.
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DOI：
10.1021/bc060153x
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发表时间：
2006-11
影响因子：
4.7
通讯作者：
S. Yellappa;J. Seetharamappa;Lisa M. Rogers;R. Chitta;R. Singhal;F. D’Souza
中科院分区：
文献类型：
--
作者：
S. Yellappa;J. Seetharamappa;Lisa M. Rogers;R. Chitta;R. Singhal;F. D’Souza
用紫外-可见吸收光谱、圆二色性光谱、电化学和凝胶电泳等方法研究了水溶性四甲基吡啶基卟啉钴（TMPyP）Co及其高缺电子衍生物四甲基吡啶基-β-八溴卟啉钴（Br（8）TMPyP）Co与核酸的结合.这些络合物与多核苷酸的滴定过程中的吸收光谱的变化揭示了在卟啉Soret带的最大吸收和减色性的移位。固有结合常数在10（5）-10（6）M（-1）范围内。这些值更高的电子缺陷（Br（8）TMPyP）Co。诱导CD带注意到在Soret区域的复合物，由于这些复合物与不同的多核苷酸的相互作用，和CD光谱的分析支持主要是外部模式的结合。电化学研究表明，（TMPyP）Co和（Br（8）TMPyP）Co在氧存在下优先在A-T碱基对区域切割多核苷酸。凝胶电泳实验进一步支持核酸的切割。结果表明，溴化β-吡咯卟啉（Br（8）TMPyP）Co与核酸的结合力较（TMPyP）Co更强，切割效率更高，为生物技术中特异性切割双链DNA提供了一种独特的工具。
The binding of nucleic acids by water-soluble cobalt(II) tetrakis-N-methylpyridyl porphyrin, (TMPyP)Co, and its highly electron-deficient derivative cobalt(II) tetrakis-N-methyl pyridyl-beta-octabromoporphyrin, (Br(8)TMPyP)Co, was investigated by UV-visible absorption, circular dichroism (CD), and electrochemical and gel electrophoresis methods. The changes of the absorption spectra during the titration of these complexes with polynucleotides revealed a shift in the absorption maxima and a hypochromicity of the porphyrin Soret bands. The intrinsic binding constants were found to be in the range of 10(5)-10(6) M(-1). These values were higher for the more electron-deficient (Br(8)TMPyP)Co. Induced CD bands were noticed in the Soret region of the complexes due to the interaction of these complexes with different polynucleotides, and an analysis of the CD spectra supported a mainly external mode of binding. Electrochemical studies revealed the cleavage of polynucleotides by (TMPyP)Co and (Br(8)TMPyP)Co in the presence of oxygen preferentially at the A-T base pair region. Gel electrophoresis experiments further supported the cleavage of nucleic acids. The results indicate that the beta-pyrrole brominated porphyrin, (Br(8)TMPyP)Co, binds strongly and cleaves nucleic acids efficiently as compared with (TMPyP)Co. This electrolytic procedure offers a unique tool in biotechnology for cleaving double-stranded DNA with specificity at the A-T regions.