School Kid Level Blunder

My 14 yo daughter is studying acids and bases in chemistry this year. Which is why I got a refresher that acids release hydrogen ions (H⁺) when dissolved in water; and bases either accept those hydrogen ions (H⁺) or release hydroxide ions (OH^-) when dissolved in water. Very elementary part of chemistry.

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Linus Pauling. In 1952, he hadn’t yet won a Nobel but was universally acknowledged as one of the world’s greatest chemists. At the time, the structure of the to-be-famous DNA molecule was unknown. Many teams were trying to figure it, including Watson and Crick. As also was Pauling – DNA was a molecule, so who better than a chemist to attack the problem? By the end of 1952, Pauling thought he had figured it, and communicated as much to his son, Peter, who was at Cambridge, same as Watson and Crick.

 

DNA’s structure was a rivalry – the British didn’t want to lose to the Americans. Peter mentions what his British colleagues were saying:

“You know how children are threatened “You had better be good or the bad ogre will come get you.” Well, for more than a year, Francis [Crick] and others have been saying to the nucleic acid people at King's “You had better work hard or Pauling will get interested in nucleic acids.’’

Such then was the aura and fear of Linus Pauling. And now it sounded like their worst fears had come true, that Pauling had cracked DNA’s structure.

 

Watson asked Peter to get a copy of Pauling’s paper and “instantly devoured” it, writes Mario Livio in Brilliant Blunders:

“After staring at the illustrations for a few minutes, he couldn't believe his eyes. Pauling's structure, with the phosphates in the center and the bases on the outside… was preposterously wrong!”

 

Wrong is one thing, why did Watson call it “preposterously” wrong? For one, Watson and colleagues had previously considered a model with 3 strands, and dismissed it when on further analysis. And Pauling’s model had 3 strands (DNA, as we all know since Watson and Crick’s eventual success, has 2 strands, the famous double helix).

 

But still, that didn’t warrant calling Pauling’s attempt “preposterously” wrong. No, the reason for calling it that was a very basic error in the model:

“The world's greatest chemist constructed a completely defective model, and the model was wrong not because of some subtle biological feature but because of a major blooper in the most basic chemistry.”

And that “blooper” was what even a school student could have understood!

“Pauling's nucleic acid molecule was simply not an acid at all. That is, it could not release positively charged hydrogen atoms when dissolved in water, the very definition of an acid.”

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But don’t feel too bad for Pauling. He would go on to become the only person to win two unshared Nobel Prizes (Chemistry in 1954 and Peace in 1962). He applied quantum mechanics to atomic structures and established how atoms share electrons. A genius and more. And also the man who committed that “blooper” when it came to the structure of DNA. Such is life.