Watson and Crick knew that the triple helix model of DNA that Linus Pauling had proposed was incorrect. What evidence did they have for such a conclusion?

Question

anonymous · Answer

I know why the Pauling model was wrong, but I know Rosalind Franklin pointed Watson and Crick in the right direction. So..my question is, what did Watson and Crick know before Frankin came in?

anonymous · Answer

@Abhisar

abhisar · Answer

Actually they did not perform any experiment, but intelligently enough, synthesized the data provided by Wilkins and Franklin about the chemical and physical aspects of DNA to develop a suitable model for its structure.

aaronq · Answer

i think chargaff's findings (equal ratios of A-T and G-C) that made them realize the triple helix form of DNA wasn't correct. 

It has to do with the bonding, typically nucleotides bind (through H-bonds) in a "watson-crick" type of bonding, and a triple helix would involve "hoogsteen" type bonding. 

This would yield unequal ratios of the nucleotides, for example, you'd have:

ACACACACACACA
 watson-crick
TGTGTGTGTGTGT  


ACACACACACACA
   watson-crick
TGTGTGTGTGTGT   
     hoogsteen
ACACACACACACA  


im not about to draw these things, but you can look them up