Photocontrol of DNA melting/hybridization at constant temperature accepted in Nano Letters!

Thursday, December 17th 2015

17 Dec 2015. Our paper "Photodependent melting of unmodified DNA using a photosensitive intercalator: a new and generic tool for photoreversible assembly of DNA nanostructures at constant temperature" has just been accepted in Nano Letters.


Abstract
External control of DNA melting and hybridization, a key-step in bio- and DNA nanotechnology, is commonly achieved with temperature. The use of light to direct this process is a challenging alternative, which has been only possible with a DNA modification, such as covalent grafting or mismatch introduction, so far. Here we describe the first photocontrol of DNA melting that relies on the addition of a molecule that non-covalently interacts with unmodified DNA and affects its melting properties in a photoreversible and highly robust manner, without any prerequisite in the length or sequence of the target DNA molecule. We synthesize azobenzene-containing guanidinium derivatives and show that a bivalent molecule with a conformation-dependent binding mode, AzoDiGua, strongly increases the melting temperature (Tm) of DNA under dark conditions because its trans isomer intercalates in the DNA double helix. Upon UV irradiation at 365 nm, the trans-cis isomerization induced the ejection of AzoDiGua from the intercalation binding sites, resulting in a decrease in Tm up to 18 °C. This illumination-dependent Tm shift is observed on many types of DNA, from self-complementary single-stranded or double-stranded oligonucleotides to long genomic duplex DNA molecules. Finally, we show that simply adding AzoDiGua allows us to photoreversibly control the assembly/disassembly of a DNA nanostructure at constant temperature, as demonstrated here with a self-hybridized DNA hairpin. We anticipate that this strategy will be the key-ingredient of a new and generic way to place DNA-based bio- and nanotechnologies under a dynamic control by light.

Reference:

Photodependent melting of unmodified DNA using a photosensitive intercalator: a new and generic tool for photoreversible assembly of DNA nanostructures at constant temperature
A. Bergen, S. Rudiuk, M. Morel, T. Le Saux, H. Ihmels, D. Baigl*
Nano Lett. 2016,16, 773–780
 - doi : 10.1021/acs.nanolett.5b04762




Damien Baigl

ASAP papers from NATURE
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