Editing Alpha helix (section)

== Dynamical features ==
Alpha-helices in proteins may have [[low-frequency collective motion in proteins and DNA|low-frequency]] accordion-like motion as observed by the [[Raman spectroscopy]]<ref name="pmid7115900">{{cite journal | vauthors = Painter PC, Mosher LE, Rhoads C | title = Low-frequency modes in the Raman spectra of proteins | journal = Biopolymers | volume = 21 | issue = 7 | pages = 1469–72 | date = July 1982 | pmid = 7115900 | doi = 10.1002/bip.360210715 | doi-access = free }}</ref> and analyzed via the quasi-continuum model.<ref name="pmid6362659">{{cite journal | vauthors = Chou KC | title = Identification of low-frequency modes in protein molecules | journal = The Biochemical Journal | volume = 215 | issue = 3 | pages = 465–9 | date = December 1983 | pmid = 6362659 | pmc = 1152424 | doi = 10.1042/bj2150465 }}</ref><ref name="pmid6428481">{{cite journal | vauthors = Chou KC | title = Biological functions of low-frequency vibrations (phonons). III. Helical structures and microenvironment | journal = Biophysical Journal | volume = 45 | issue = 5 | pages = 881–9 | date = May 1984 | pmid = 6428481 | pmc = 1434967 | doi = 10.1016/S0006-3495(84)84234-4 | bibcode = 1984BpJ....45..881C }}</ref> Helices not stabilized by tertiary interactions show dynamic behavior, which can be mainly attributed to helix fraying from the ends.<ref>{{cite journal | vauthors = Fierz B, Reiner A, Kiefhaber T | title = Local conformational dynamics in alpha-helices measured by fast triplet transfer | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 106 | issue = 4 | pages = 1057–62 | date = January 2009 | pmid = 19131517 | pmc = 2633579 | doi = 10.1073/pnas.0808581106 | bibcode = 2009PNAS..106.1057F | doi-access = free }}</ref>