Monitoring guanine photo-oxidation by enantiomerically resolved Ru(II) dipyridophenazine complexes using inosine-substituted oligonucleotides

作者：Keane Paraic M^*; Poynton Fergus E; Hall James P; Clark Ian P; Sazanovich Igor V; Towrie Michael; Gunnlaugsson Thorfinnur; Quinn Susan J; Cardin Christine J; Kelly John M

来源：Faraday Discussions, 2015, 185: 455-469.

DOI：10.1039/c5fd00085h

The intercalating [Ru(TAP)(2)(dppz)](2+) complex can photo-oxidise guanine in DNA, although in mixed-sequence DNA it can be difficult to understand the precise mechanism due to uncertainties in where and how the complex is bound. Replacement of guanine with the less oxidisable inosine (I) base can be used to understand the mechanism of electron transfer (ET). Here the ET has been compared for both Lambda- and Delta-enantiomers of [Ru(TAP)(2)(dppz)](2+) in a set of sequences where guanines in the readily oxidisable GG step in {TCGGCGCCGA}(2) have been replaced with I. The ET has been monitored using picosecond and nanosecond transient absorption and picosecond time-resolved IR spectroscopy. In both cases inosine replacement leads to a diminished yield, but the trends are strikingly different for Lambda- and Delta-complexes.

• 出版日期2015