"An error in model building"

Date:
1967
Reference:
PP/CRI/H/4/8
Catalogue details

Licence: In copyright

Credit: "An error in model building". Source: Wellcome Collection.

    5/55
    About a year ago Dr S.R. Pele and Miss M. G.E. Welton published two papers' in Nature purporting to show that it is possible to fit amino-acids stereoehemically to their codons 11 . They described how they built models using Courtauld space-filling components, but it was not possible to tell from their very brief descriptions whether their models were stereoehemically acceptable. I therefore corresponded with Dr Pele and he was kind enough to show me some of their models. Dr Pele produced several examples for me to examine but I will comment here only on their model of lysine fitted to AAG, as illustrated in the photograph of Fig. 2 of the first of their two papers'. This model was stereoehemically unacceptable for the following reasons: 1. The terminal - NH* group of the lysine was built as jjft NHg. 2. In two places (one in the amino acid, one in the triplet) adjacent methyl groups were in the eclipsed rather than the staggered configuration. 3. In two cases an ^>NH, which should either make a satisfactory hydrogen bond, or at least be free to make one to a water molecule, was pointing directly at a hydrophobic group. Further inspection revealed a more basic error. Dr Pele and Miss Welton had unfortunately not understood correctly the
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