The Triple Helix

We have seen Paulings paper on Nucleic Acid. Have you? It contains several very bad mistakes. In addition, we suspect he has chosen the wrong type of model.

-James Watson, letter to Max Delbrück, February 20, 1953.

We were very interested to see that a model of the Pauling-Corey “triple helix” structure of DNA has been built by Farooq Hussain.  As Hussain notes on his website, the model was constructed based on drawings published by Linus Pauling and Robert Corey in their paper detailing the incorrect structure.

The proposed triple helix structure of DNA. Model by Farooq Hussain.

Hussain’s representation of the triple helix is striking; especially so when compared with Watson and Crick’s far more elegant and intuitive double helix, surely the most famous molecule in history.

Double helix model, courtesy of P. Shing Ho.

Indeed, Watson was well within his right to feel confident in his February letter to Delbrück.  As he noted before closing, “Today I am very optimistic since I believe I have a very pretty model, which is so pretty I am surprised no one has thought of it before.”

For more on the triple helix, see our write-up on the subject, published in April 2009.

3 Responses

  1. LP’s model combined the most essential elements of both the A & B structures of DNA, because he was relying on the Astbury data. He made the model fit the data, even though it broke some basic laws of chemistry. A technical error also pointed him in the direction of a triple helix. Boldness = always an LP trait.

  2. Rosalind Franklin noted that Pauling’s model incorporated the essential elements of both the A & B DNA structures. This was, of course, because LP relied on the Astbury data – which was rudimentary in nature. A technical error also pointed him in the wrong direction, to that of a triple helix.

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