The Interaction of Quinacrine and Its Analogs with Polyribonucleotides. 2. Theory

摘要

A series of molecular orbital (MO) calculations have been carried out on quinacrine and this dye intercalated into miniature double-helices in an attempt to understand the three-dimensional structures of the dye intercalated into double-stranded polyribonucleotides, poly(A)·poly(U) and poly(I)·poly(C), and some of their spectroscopic properties. The AM1 calculations demonstrate that QAC dication intercalates more preferentially into the major groove of minihelices than the minor groove. The calculations also provide information about the geometry of the minihelix-QAC complex in which the cationic side chain of QAC dication at the 9-position forms a hydrogen bond with an accepter atom of base pairs in the major groove. The spectroscopic properties, such as transition moments, oscillator and rotational strengths, of QAC dication in the free and bound states are also calculated by direct MO calculations based on the CNDO/S method.