Scientists at Chalmers University of Technology in Sweden refuted the
prevailing theory that hydrogen bonds (H-bonds) bind the two strands of the
DNA together. They found out that water is the key. The results are
published in the journal Proceedings of the National Academy of Sciences of
the United States of America (PNAS).



DNA is composed of two strands with sugar molecules and phosphate groups,
and nitrogen bases in between the two strands. It has been believed that the
two single strands are bound together by hydrogen bonds. However, the
researchers found evidence that the secret to the structure of the DNA helix
may be due to the hydrophobic nature of the molecules inside the DNA. The
environment is hydrophilic, while the hydrophobic nitrogen bases push away
the water in the environment. When hydrophobic units are placed in a
hydrophobic environment, they clump together, to lessen water exposure. The
hydrogen bonds still have a crucial role, but not in holding the DNA helixes
together, instead in sorting the base pairs in the proper sequence.

This new discovery is vital in understanding how DNA reacts with its
environment.

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