Unfolding of an α‐helix in water

Kizhake V. Soman, Afshin Karimi, David A. Case

Research output: Contribution to journalArticlepeer-review

139 Scopus citations


We describe a 1 ns molecular dynamics simulation of an 18‐residue peptide (corresponding to a portion pf the H helix of myoglobin) in water. The initial helical conformation progressively frays to a more disordered structure, with the loss of internal secondary structure generally proceeding from the C‐terminus toward the N‐terminus. Although a variety of mechanisms are involved in the breaking of helical hydrogen bonds, the formation of transient turn structures, with i → i + 3 hydrogen bonds, and bifurcated hydrogen‐bond structures intermediate between α and turn or 310 structures is a common motif. In some cases a single water molecule is inserted into an internal hydrogen bond, but it is also common to have several water molecules involved in transient intermediates. Overall, the results provide new information about the detailed mechanisms by which helices are made and broken in aqueous solution.

Original languageEnglish (US)
Pages (from-to)1351-1361
Number of pages11
Issue number12
StatePublished - Oct 15 1991
Externally publishedYes

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Biomaterials
  • Organic Chemistry


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