Letter from Francis Crick to Jerry Donohue


Title:
Letter from Francis Crick to Jerry Donohue
Description:
Donohue published an article in the September 12, 1969, issue of Science (vol. 165, p. 1091), in which he questioned whether Fourier syntheses, a method for calculating the distribution of electron density from amplitudes (seen in X-ray diffraction images) and assumed bond angles of molecules in crystals--and thus a method for inferring the structure of such molecules--did in fact provide evidence for the Watson-Crick structure, specifically the base pairs, as DNA researchers like Maurice Wilkins claimed. Donohue in his article presented electron density maps of various combinations of base pairs which he claimed fit Fourier syntheses just as well as the canonical A=T and C=G pairs. He thereby implied that other base pairs and thus other structures for DNA were conceivable.. Crick, along with Maurice Wilkins and other DNA scientists, refuted Donohue's criticism and arguments in letters published in the March 27, 1970, issue of Science (vol. 167, p.1693). He did so again in this letter, challenging Donohue to further explain the results of his Fourier syntheses of his proposed base pairs.. In crystallography, a dyad (mentioned in the letter) is a two-fold symmetry, or a symmetry around two axes. A Patterson function is a technique developed in the 1920s for estimating the distances between atoms in a molecule by analyzing the intensities--the darkness--of the spots produced on a photographic plate by X-ray diffraction. This technique thus avoided the so-called phase problem in crystallography, the problem of measuring the X-rays' peaks and troughs, providing hints (though not conclusive evidence) of the internal structure of molecules.
Extent:
1 pages
Date Created:
20 May 1970
Creator:
Crick, Francis, 1916-2004
Recipient:
Donohue, Jerry (Jerry Donohue)
Source:
Original Repository. Wellcome Library for the History and Understanding of Medicine. Francis Harry Compton Crick Papers. 11646. URL. http://archives.wellcome.ac.uk/
Original Repository:
The Wellcome Library for the History and Understanding of Medicine. Francis Harry Compton Crick Papers
Right Type:
Permission Granted - No Conditions
Right Statement:
Reproduced with permission of the Wellcome Library for the History and Understanding of Medicine. and http://library.wellcome.ac.uk/
Subject:
DNA and Crystallography, X-Ray
Profiles in Science ID:
SCBBNC
NLM ID:
101584582X188
Genre:
Letters (correspondence)
Language:
English
Format:
Text
Location:
Box: 21. Folder: PP/CRI/D/2/11/1