MASS-SPECTROMETRIC AND COMPUTATIONAL STUDY OF COMPLEX-FORMATION OF NUCLEIC-ACID BASES WITH ACRYLAMIDE AS A SURROGATE FOR ASPARAGINE AND GLUTAMINE RESIDUES

In the context of the problem of nucleic acid-protein interactions, th ermodynamic and geometrical parameters of complexes of methylated nucl eic acid bases with acrylamide (as a model of the side chains of aspar agine and glutamine) were investigated. Enthalpies of formation of nuc leic acid base-acrylamide complexes, determined experimentally by mean s of temperature-dependent field ionization mass spectrometry, were in reasonable agreement with the interaction energies calculated theoret ically using atom-atom potential functions. A stability order for base -acrylamide complexes was determined: m(9)Gua greater than or equal to m(2)(1,4) Cyt greater than or equal to m(1) Cyt > m(9) Ade > m(3)(1,4 ,4) Cyt > m(1) Ura > m(2)(1,3) Thy. The geometries of the most energet ically favourable complexes are determined and discussed. (C) 1998 Joh n Wiley & Sons, Ltd.