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.
January 1, 2011
A comparison of left and right handed DNA double-helix models.
Filed under: Interesting chemistry — Tags: B-DNA, computing, conformational analysis, dispersion energy, DNA duplex, interaction energy, optical rotation, van der Waals, Z-DNA — Henry Rzepa @ 8:23 pm
December 29, 2010
The handedness of DNA: an unheralded connection.
Filed under: Interesting chemistry — 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 — Henry Rzepa @ 11:14 am
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!).
References
- 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