Left-handed deoxyribonucleic acid double helix in solution

Abstract

Magnetic shielding constants were calculated for the synthetic deoxyribonucleic acid (DNA) double helix poly(dG-dC).cntdot.poly(dG-dC) from the x, y and z coordinates of Z-DNA of Rich and co-workers, taking into account the contribution to shielding from ring current effects and effects from the diamagnetic and paramagnetic components of the atomic magnetic anisotropy. Comparison of the calculated shielding from ring current effects and effects from the diamagnetic and paramagnetic components of the atomic magnetic anisotropy. Comparison of the calculated shielding values with the experimentally observed NMR shift data for poly(dG-dC).cntdot.poly(dG-dC) in high salt solution shows striking agreement for Z-DNA and considerable deviation for B-DNA, indicating that this synthetic DNA double helix in high salt solution can assume the spatial configuration of the left-handed Z-DNA double helix known to occur in crystals.