LONG-RANGE PHOTOINDUCED ELECTRON-TRANSFER THROUGH A DNA HELIX
LONG-RANGE PHOTOINDUCED ELECTRON-TRANSFER THROUGH A DNA HELIX
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DOI：
10.1126/science.7802858
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发表时间：
1993-11-12
期刊：
影响因子：
56.9
通讯作者：
BARTON, JK
中科院分区：
文献类型：
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作者：
MURPHY, CJ;ARKIN, MR;BARTON, JK
在一个15碱基对DNA双链的5'端连接的金属嵌入体之间，证明了在超过40埃的距离上的快速光诱导电子转移。合成了一个低聚体，供体为Ru(phen)2dppz2+ （phen，菲罗啉和dppz，二吡啶吩嗪），受体为Rh(phi)2phen3+ （phi，菲罗醌二亚胺）。这些金属配合物从螺旋末端插入一个或两个基级。钌修饰的寡核苷酸与未修饰的补体杂交时发光强烈，而钌修饰的低聚物与铑修饰的低聚物杂交时则没有可检测到的发光。时间分辨研究指出，淬火速率的下限为每秒10(9)。在phen配合物不插层的条件下，Ru(phen)3（2+）和Rh(phen)3（3+）对两个互补八聚体的金属化没有观察到猝灭现象。因此，DNA双链的堆叠芳香杂环作为一种有效的介质，在很长的距离上偶联电子供体和受体。
Rapid photoinduced electron transfer is demonstrated over a distance of greater than 40 angstroms between metallointercalators that are tethered to the 5' termini of a 15-base pair DNA duplex. An oligomeric assembly was synthesized in which the donor is Ru(phen)2dppz2+ (phen, phenanthroline, and dppz, dipyridophenazine) and the acceptor is Rh(phi)2phen3+ (phi, phenanthrenequinone diimine). These metal complexes are intercalated either one or two base steps in from the helix termini. Although the ruthenium-modified oligonucleotide hybridized to an unmodified complement luminesces intensely, the ruthenium-modified oligomer hybridized to the rhodium-modified oligomer shows no detectable luminescence. Time-resolved studies point to a lower limit of 10(9) per second for the quenching rate. No quenching was observed upon metallation of two complementary octamers by Ru(phen)3(2+) and Rh(phen)3(3+) under conditions where the phen complexes do not intercalate. The stacked aromatic heterocycles of the DNA duplex therefore serve as an efficient medium for coupling electron donors and acceptors over very long distances.