Posts Tagged ‘solvation algorithms’

Why are α-helices in proteins mostly right handed?

Saturday, April 9th, 2011

Understanding why and how proteins fold continues to be a grand challenge in science. I have described how Wrinch in 1936 made a bold proposal for the mechanism, which however flew in the face of much of then known chemistry. Linus Pauling took most of the credit (and a Nobel prize) when in a famous paper[cite]10.1073/pnas.37.4.205[/cite] in 1951 he suggested a mechanism that involved (inter alia) the formation of what he termed α-helices. Jack Dunitz in 2001[cite]10.1002/1521-3773(20011119)40:22%3C4167::AID-ANIE4167%3E3.0.CO;2-Q[/cite] wrote a must-read article[cite]10.fgkwqb[/cite] on the topic of “Pauling’s Left-handed α-helix” (it is now known to be right handed). I thought I would revisit this famous example with a calculation of my own and here I have used the ωB97XD/6-311G(d,p) DFT procedure[cite]10.1021/ct100469b[/cite] to calculate some of the energy components of a small helix comprising (ala)6 in both left and right handed form.