9.
B Type DNA
 Watson
went to London with news of Pauling's error, pointing
out that Pauling's mistake was somewhat similar to the
mistake he and Crick had made with their DNA model the
previous year. Watson's concentration on helical arrangements
annoyed Rosalind Franklin, especially when he implied
she was misinterpreting her X-ray photographs.
Maurice
Wilkins was more sympathetic, however, and told Watson
about a new form of DNA that Franklin had discovered
that summer. If the DNA were surrounded by lots of water
this new 'B' form occured. Wilkins showed Watson an
X-ray photograph of this new structure.
Watson
and Wilkins both agreed that the new photograph was
incredibly strong evidence for a helix structure. King's
College were trying to find a three chain structure,
but had difficulties in making the bases fit together
between external sugar-phosphate backbones.
Watson
decided to try to find a two chain structure. On his
train ride back to Cambridge he drew a sketch of Wilkin's
X-ray photograph from memory.
Next
Page
|
