Construction and Energy Transfer Behavior of Sequential Chromophore Arrays on an Oligo-DNA Assembly

Publisher Website
Google Scholar
Abstract
Sequential arrays of chromophores at regulated distances were constructed on a non-covalent DNA molecular assembly system in aqueous media. Photo-induced energy transfer behaviors were then observed. We designed a number of chromophore/oligo-DNA conjugates with varying residue sequences. The chromophores eosin (Eo), Texas Red (TR) and tetramethylrhodamine (TMR) were employed as energy donor, acceptor and mediator, respectively, based on overlapping excitation and emission spectra. The chromophores were attached to the 5'-terminals of 10 residue oligo-DNAs using aminolinkers. Arrangements of Eo-TMR or TMR-TR were constructed by duplex formation of conjugates with a 20 mer matrix oligo-DNA comprising complementary sequences to the conjugates. Single-step photo-induced energy transfer from Eo to TMR and from TMR to TR was confirmed for the duplex. The three kinds of chromophore conjugates were then mixed with longer matrix oligo-DNAs (30 or 40 mer) consisting of complementary sequences to the conjugates, producing Eo-(TMR) n -TR ( n = 1 or 2) arrays. Multi-step photo-induced energy transfer from Eo to TR through the TMR mediator(s) was observed on the molecular assemblies. This photo-energy transmission system offers a good model for artificial photosynthetic systems.