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Stability of secondary structural elements in a solvent‐free environment: the α helix
Author(s) -
Kaltashov Igor A.,
Fenselau Catherine
Publication year - 1997
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/(sici)1097-0134(199702)27:2<165::aid-prot2>3.0.co;2-f
Subject(s) - chemistry , solvation , melittin , protein secondary structure , helix (gastropod) , molecule , crystallography , hydrogen bond , solvation shell , chemical physics , solvent , phase (matter) , protonation , computational chemistry , thermodynamics , ion , peptide , organic chemistry , physics , ecology , biochemistry , snail , biology
The stability of the α helix as an element of secondary structure is examined in the absence of solvation, in the gas phase. Mass‐analyzed ion kinetic energy (MIKE) spectrometry was applied to measure intercharge repulsion and intercharge distance in multiply protonated melittin, a polypeptide known to possess a stable helical structure in a number of different environments. The experimental results, interpreted in combination with molecular mechanics calculations, suggest that triply charged melittin retains its secondary structure in the gas phase. The stability if the α‐helical conformation of the polypeptide in the absence of solvent molecules reflects the fact that a network of intrinsic helical hydrogen bonds is energetically more favorable than unfolded conformations. © 1997 Wiley‐Liss, Inc.