The gene as a nucleoprotein

From Florence Bell's X-ray studies, Astbury was able to calculate that the spacing between successive nucleotides in a nucleic acid chain was 3.4 Angstroms - almost exactly the same distance as that between individual amino acid side chains in a polypeptide.

Speaking of this remarkable correlation, Bell said:

'We were "ecstatic" to find a spacing identity-but not really surprised, because we had been hoping to find some relationship. Astbury considered that the nucleic acids were templates for protein duplication and organization, and held the polypeptide chains stretched and parallel for the division process.'

For Astbury, this suggested that proteins and nucleic acids might might somehow work together:

'The significance of these findings for chromosome structure and behaviour will be obvious. It seems difficult to believe that it is no more than a coincidence that thymonucleic acid consists of a long succession of nucleotides spaced at a distance so nearly equal to that of the long succession of amino-acid residues in a fully extended polypeptide. Rather it is a stimulating thought that probably the interplay of proteins and nucleic acids in the chromosomes is largely based on this very fact, and that some critical stage in mitosis, involving elongation of the protein chains, is realized in close co-operation with the dominating period of the interacting nucleotides.'

(Astbury & Bell, 1938, p.747)

In 1941, the cytologist Jack Schultz used the term 'nucleoprotein' to describe these complexes of proteins and nucleic acids, and argued that they possessed all the necessary properties required of a gene. (Schultz, 1941).

So, far from believing that genetic information was confined only to proteins, Astbury envisaged the gene as a nucleoprotein complex. He was well aware, however, that within this complex, the DNA molecule might have a very significant role to play - as is shown in the following letter which he wrote in 1945.

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