1.
J Am Chem Soc
; 127(49): 17241-4, 2005 Dec 14.
Artigo
em Inglês
| MEDLINE
| ID: mdl-16332072
RESUMO
We analyzed the response to strain of an infinite polyalanine chain in the alpha-helical conformation using density functional theory. Under compressive strain the alpha-helix is found to undergo structural transitions to a pi-helix when the length of the helix is reduced by more than 10%. Under tensile strain the structure changes into a 3(10)-helix when the length is stretched by more than 10%. Our analysis of these transitions shows that they proceed essentially in two steps: At first there is mainly a length change, and only with some delay the helix twist adjusts.