The Importance of the Hydrogen Bond
Hydrogen bonding is essential to the three-dimensional structure of DNA. These bonds do not, however, contribute largely to the stability of the double helix. Hydrogen bonds are very weak interactions and the orientation of the bases must be just right for the interactions to take place. While the large number of hydrogen bonds present in a double helix of DNA leads to a cumulative effect of stability, it is the interactions gained through the stacking of the base pairs that leads to most of the helical stability. Hydrogen bonding is most important for the specificity of the helix. Since the hydrogen bonds rely on strict patterns of hydrogen bond donors and acceptors, and because these structures must be in just the right spots, hydrogen bonding allows for only complementary strands to come together: A- T, and C-G. This complementary nature allows DNA to carry the information that it does.