Henry Rzepa's Blog Chemistry with a twist

January 1, 2011

A comparison of left and right handed DNA double-helix models.

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.

(more…)

December 29, 2010

The handedness of DNA: an unheralded connection.

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!).

(more…)

References

  1. 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

Powered by WordPress