Correlation of hydrophobicity and packing in A-DNA oligonucleotides.

A-DNA oligomers pack in a slanted fashion with the terminal base pairs abutting into the minor groove of neighboring molecules unlike the other forms of DNA which pack by vertically stacking one over the other into helical columns. To explain the differences in packing we have advanced a hypothesis that the orientation of the sugar-phosphate backbone is different in A-DNA from that in the other forms of DNA, mainly due to the differences in the sugar puckering.