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Unfolding of an α‐helix in water
Author(s) -
Soman Kizhake V.,
Karimi Afshin,
Case David A.
Publication year - 1991
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360311202
Subject(s) - chemistry , myoglobin , hydrogen bond , molecule , aqueous solution , helix (gastropod) , crystallography , molecular dynamics , protein secondary structure , structural motif , turn (biochemistry) , alpha helix , computational chemistry , circular dichroism , organic chemistry , biochemistry , ecology , snail , biology
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 3 10 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.