Posts Tagged ‘van der Waals’
Saturday, January 1st, 2011
When Watson and Crick (WC) constructed their famous 3D model for DNA, they had to decide whether to make the double helix left or right handed. They chose a right-handed turn, on the grounds that their attempts at left-handed models all “violated permissible van der Waals contacts“. No details of what these might have been were given in their original full article (or the particular base-pairs which led to the observation). This follow-up to my earlier post explores this aspect, using a computer model.
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Tags:B-DNA, computing, conformational analysis, dispersion energy, DNA duplex, interaction energy, optical rotation, van der Waals, Z-DNA
Posted in Interesting chemistry | 7 Comments »
Wednesday, December 29th, 2010
Science is about making connections. Plenty are on show in Watson and Crick’s famous 1953 article on the structure of DNA[1] but often with the tersest of explanations. Take for example their statement “Both chains follow right-handed helices“. Where did that come from? This post will explore the subtle implications of that remark (and how in one aspect they did not quite get it right!).
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References
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J.D. WATSON, and F.H.C. CRICK, "Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid", Nature, vol. 171, pp. 737-738, 1953. http://dx.doi.org/10.1038/171737a0
Tags:Bijvoet, chemist, chiroptical, d(CGCG), Derek Barton, dispersion forces, DNA duplex, Historical, Marcus du Sautoy, Note, Odile Crick, professional artist, Tartaric Acid, van der Waals, watoc11, Watson Crick, Web sense, Z-DNA
Posted in Interesting chemistry | 8 Comments »