STRUCTURAL AND ELECTRONIC PROPERTY CHANGES OF THE NUCLEIC-ACID BASES UPON BASE-PAIR FORMATION

A systematic study of structures and electronic properties has been ca rried out for the nucleic acid bases adenine, guanine, thymine, and cy tosine and for the base pairs adenine-thymine and guanine-cytosine. We focus our attention on these properties, which experience significant changes when single nucleic bases join to form base pairs. Such prope rties are expected to play an important role during the formation of t he DNA molecule in its B conformation. All-electron calculations with inclusion of correlation effects were performed according to the local and nonlocal density functional approaches. We compare our results wi th previous ab initio and semiempirical values and with available expe rimental data. Advantages and disadvantages for these density function al-based methods are discussed. We conclude that applications of such models to investigate larger compounds of a similar nature are promisi ng. (C) 1994 by John Wiley and Sons, Inc.