DNA has become very attractive as scaffold for functional molecules on the nanometre scale.¹ The sequence specific insertion of modified nucleotides using automated DNA synthesis allows for the creation of new designer molecules with a wide range of potential applications. We have established a general synthetic route to porphyrin-nucleosides and their subsequent site specific incorporation into oligonucleotides to create multiporphyrin arrays. Up to eleven consecutive porphyrins could be incorporated into DNA giving access to a multiporphyrin array of approximately 10 nm in length, which corresponds to the highest amount of DNA modification with a large hydrophobic metal complex.² The spectroscopic data and structure calculations indicate the formation of a stable helical array in the single strand porphyrin-DNA. The π-stack of the porphyrins leads to strong electronic interaction between the chromophores. A zipper array with induced stability and energy transfer properties has recently been realised, providing access to the first reversible photonic wire based on a DNA scaffold.³

We will present our latest results in terms of structure analysis of porphyrin modified DNA, which includes the stepwise built up of a porphyrin-DNA system and its detailed analysis using CD spectroscop and thermal analysis with absorption and fluorescence spectroscopy. In addition, a novel LNA derived porphyrin building block will be discussed which shows large differences in excitonic coupling depending on the DNA sequence.⁴ Several applications of porphyrin-DNA will also be described, including highly sensitive genosensors⁵ and DNA origami nanopores.⁶

References

1.   T. J. Bandy, A. Brewer, J. R. Burns, G. Marth, T. Nguyen and E. Stulz, Chem. Soc. Rev., 2011, 40, 138-148.

2.   L. A. Fendt, I. Bouamaied, S. Thöni, N. Amiot and E. Stulz, J. Am. Chem. Soc., 2007, 129, 15319-15329.

3.   T. Nguyen, A. Brewer and E. Stulz, Angew. Chem. Int. Ed., 2009, 48, 1974-1977.

4.   D. G. Singleton, R. Hussain, G. Siligardi, P. Kumar, P. J. Hrdlicka, N. Berova, E. Stulz, Org. Biomol. Chem., 2016, in print; DOI: 10.1039/C5OB01681A

5.   I. Grabowska, D. G. Singleton, A. Stachyra, A. Gora-Sochacka, A. Sirko, W. Zagorski-Ostoja, H. Radecka, E. Stulz, J. Radecki, Chem. Commun., 2014, 50, 4196-4199.

6.   a) J. R. Burns, E. Stulz and S. Howorka, Nano Lett., 2013, 13, 2351-2356; b) J. R. Burns, K. Gopfrich, J. W. Wood, V. V. Thacker, E. Stulz, U. F. Keyser and S. Howorka, Angew. Chem.-Int. Edit., 2013, 52, 12069-12072.