Hydrogen bonding between nucleic acid constituents and amino acid amide group

The formation of hydrogen-bonded complexes between 9-ethyladenine and acetamide in chloroform solution has been studied by infrared spectroscopy. Comparison of the mixed solution spectra with the sum of the spectra of the separate monomers in solution shows that cyclic heterodimers are formed when acetamide binds to adenine base. Information is also obtained about the atomic arrangement of these heterodimers, where acetamide is bound to adenine base predominantly through the pyrimidine ring. Hydrogen bonds of this nature have been also observed for concentrated aqueous solutions of adenosine 5′-monophosphate in the presence of acetamide using Raman spectroscopy.