In 1953, James Watson and Francis Crick published a breakthrough paper entitled, "Molecular Structure of Nucleic Acids".

This paper is somewhat different from the "standard" scientific paper, it was a short letter to the British journal Nature.

These letters are written without distinct sections. Nevertheless, their structure is similar to that of the more standard research paper.

Read the paper.  If you need an accessible refresher on DNA, follow this link.

The abstract is
contained in first
We wish to suggest a structure for the salt of deoxyribose nucleic acid (D.N.A.). This structure has novel features which are of considerable biological interest.

In their introduction, paragraphs 2 and 3, they describe a model for DNA structure proposed by Linus Pauling and Robert Corey, as well as model by Fraser.


Pauling and Corey had been working on the structure of proteins since the 1930s.

In 1951, using data from X-ray diffraction experiments, they described two common structural motifs present in proteins, the α-helix and the β-sheet.

Pauling was a particularly intimidating competitor, since he had a long history of important contributions, including early work on the nature of the chemical bond.

He won the Nobel prize in Chemistry in 1954, and a second Nobel prize for Peace in 1963 for his work against the testing and proliferation of nuclear weapons.

Questions to answer
  • Watson and Crick found the Pauling/Corey model of DNA unconvincing, why? 

In the next two paragraphs Watson and Crick describe their results, their model for DNA's structure.

There are some chemical terms here and later in the paper, such as the description of chemical linkages, that you may not understand.

We wish to put forward a radically different structure for the salt of deoxyribose nucleic acid. This structure has two helical chains chains each coiled round the same axis.
Here are the terms you need to understand
  • axis - an imaginary line about which symmetry relationships occur
  • dyad - a two-fold axis of symmetry.  If you can rotate the structure by 180° and it looks exactly the same, then it has a dyad symmetry axis.
  • Å - Ångstrom - a unit of length, 10-10 meters.

In the next paragraph the authors describe their assumption that the bases are in the " keto" rather than the " enol" forms.

These are tautomers of one another, they contain the same atoms but in different arrangements. As you can appreciate, the overall shape of these groups of atoms differs considerably.

The form of the base really makes a difference in how they interact with one another.

Questions to answer
  • They describe the novel features of their model and their implications.   What are they

Use Wikipedia | revised 20 November 2010