Photoisomerizable Guanosine Derivative as a Probe for DNA Base-Pairing in Langmuir Monolayers.

M Ličen,S Masiero,I Drevenšek-Olenik

doi:10.1021/acs.langmuir.9b00429

Abstract

Mixtures of azo-functionalized amphiphilic derivatives of guanosine and of amphiphilic derivatives of other DNA nucleobases were deposited at an air–water interface and repeatedly irradiated with light of 340 and 440 nm wavelengths. The consequent switching between cis and trans configurations of the azobenzene moiety caused changes in the surface pressure of the film, which were analyzed using a model based on the two-dimensional Van der Waals equation of state. For mixed films of guanosine and cytidine derivatives, the analysis revealed a significant modification of the strength of intermolecular interaction caused by the optical irradiation, while no such modifications were identified in mixed films involving other nucleobases. The difference is attributed to light-induced breaking of the hydrogen bonding that is established only between specific nucleobases. The results demonstrate that photosensitive nucleoside derivatives can be used as an efficient probe for base-pairing in Langmuir monolayers.

Highlights

The Langmuir−Blodgett (LB) technique enables precise fabrication of large-scale two-dimensional materials,[1,2] which can be used in photovoltaics[3] and molecular electronics,[4,5] as model membranes[6] and functionalized coatings,[7] etc.[8]
For mixed films of guanosine and cytidine derivatives, the analysis revealed a significant modification of the strength of intermolecular interaction caused by the optical irradiation, while no such modifications were identified in mixed films involving other nucleobases
Surface pressure of films formed at the air−water interface was measured, so we developed a model describing photoinduced modifications of the surface pressure in such films

Summary

Introduction

The Langmuir−Blodgett (LB) technique enables precise fabrication of large-scale two-dimensional materials,[1,2] which can be used in photovoltaics[3] and molecular electronics,[4,5] as model membranes[6] and functionalized coatings,[7] etc.[8] An attractive extension of the standard LB methodology is adding some dynamic properties to the LB films by constructing them from molecules containing a photoactive moiety, making it possible to influence their structural and chemical and physical properties via optical irradiation Such most common moieties are azobenzene derivatives, which change their configuration from a stretched trans to a bent cis isomer when irradiated with light of one wavelength (typically in the UV spectral range) and back from a cis to a trans isomer when irradiated with light of another wavelength (usually in the visible spectral range).

Results

Discussion

Conclusion