Figure 1.

Chemical structure of the methylphosphonate modified DNA backbone (top). The partial charges on the phosphorous, 3′ ester oxygen, 5′ ester oxygen, sp2 phosphoryl oxygen, methyl carbon and methyl hydrogens are 1.09, –0.397, –0.378, –0.664, –0.458 and 0.136, respectively. Schematic representations of the methylphosphonate modified DNA backbone showing the 12 phosphate groups that are modified to methylphosphonates in the MD simulations described here (bottom).