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Characterization of the structure and dynamics of mastoparan‐X during folding in aqueous TFE by CD and NMR spectroscopy
Author(s) -
Crandall Yvette M.,
Bruch Martha D.
Publication year - 2008
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.20891
Subject(s) - chemistry , mastoparan , peptide , folding (dsp implementation) , nuclear magnetic resonance spectroscopy , amino acid , aqueous solution , circular dichroism , crystallography , chemical shift , two dimensional nuclear magnetic resonance spectroscopy , residue (chemistry) , stereochemistry , organic chemistry , biochemistry , receptor , g protein , electrical engineering , engineering
Mastoparan‐X, a 14‐residue peptide found in wasp venom, does not adopt a well‐defined structure in water, but it folds into an α‐helix upon addition of trifluoroethanol (TFE). At low levels of TFE, the peptide is partially folded, passing through intermediate stages of folding as the amount of TFE is increased. These partially folded states have been characterized by CD and NMR spectroscopy, and methods to estimate the helical content from CD, chemical shift, and nuclear overhauser effect (NOE) data are compared. Variation in the sign and intensity of NOE cross‐peaks is observed in different regions of the peptide, indicative of greater mobility of the sidechains compared to the backbone of the peptide. Furthermore, variation in the sidechain mobility is observed, both between sidechains of different amino acids and within the sidechain of a given amino acid. By monitoring chemical shifts and NOE intensities as the TFE concentration is increased, the initiation site for helix formation could be identified. Furthermore, details of the peptide structure and dynamics during the folding process were elucidated. © 2007 Wiley Periodicals, Inc. Biopolymers 89: 197–209, 2008. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley. com