Molecular recognition of uracil and adenine nucleobases by Langmuir monolayers of metal complexes of amphiphilic cyclen

Abstract

The molecular recognition of purine and pyrimidine nucleobases (adenine and uracil) by the Langmuir monolayers of amphiphilic macrocyclic tetraamine (dicetylcyclen) is studied using independent methods of quartz microbalance and FTIR spectroscopy. Data show that the specific binding of pyrimidine base occurs in the presence of zinc ions and results from the formation of macrocyclic complex with metal ion followed by the coordination of uracil imide group to the metal complex. Experimental conditions that favor an increase in the efficiency of the recognition of uracil by the monolayer of metal complexes are determined. The inhibition effect of trace amounts of copper ions in the subphase containing zinc chloride-uracil mixture on the uracil recognition by the monolayer of dicetylcyclen is revealed. It is also established that the monolayer of Zn2+-dicetylcyclen complexes is inactive with respect to purine base (adenine). Therefore, the results suggest that monolayers of amphiphilic cyclen can be used as planar biomimetic modeling the function of active sites of transcription metalloproteins.