Molecular mechanics calculations of the binding of spermine to a number of solvated DNA helices have led to the development of a new model for spermine complexation. The structural details of the complexes formed with d(GCGCGCGCGC) 2 and d(ATATATATAT) 2 decamers allowed a rationalization of the observed experimental differences for binding to these two helices. For d(ATATATATAT) 2 - was concluded that spermine remains in a cross-major groove binding site. Conversely, for d(GCGCGCGCGC) 2 spermine reorientation via specific ligand-base-pair hydrogen-bond formation allows complexation along the major groove. The solvent plays an important role in differentiating the two binding modes. A mechanism of spermine complexation to natural DNA is postulated from these results. Past experimental data are also considered in the context of the new model.
|Number of pages||10|
|Journal||Proceedings of the Royal Society B: Biological Sciences|
|Publication status||Published - 1991|