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Effect of Selected Hofmeister Anions on the Secondary Structure and Dynamics of Wheat Prolamins in Gluten
Author(s) -
Wellner Nikolaus,
Bianchini David,
Mills E. N. Clare,
Belton Peter S.
Publication year - 2003
Publication title -
cereal chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.558
H-Index - 100
eISSN - 1943-3638
pISSN - 0009-0352
DOI - 10.1094/cchem.2003.80.5.596
Subject(s) - chemistry , chaotropic agent , glutenin , hofmeister series , crystallography , prolamin , gluten , electrolyte , salt (chemistry) , relaxation (psychology) , chromatography , storage protein , food science , organic chemistry , biochemistry , protein subunit , gene , psychology , social psychology , electrode
The effect of selected salts (NaCl, NaBr, NaI) with increasingly chaotropic anions on gluten prolamin secondary structure and dynamics was studied using FT‐IR and NMR spectroscopy. FT‐IR spectra indicated a small increase in intermolecular β‐sheet structures when gluten samples were incubated with low levels of NaCl and NaBr. The β‐sheet content remained constant with further NaCl addition, but was reduced again with higher NaBr concentrations. NaI addition generally reduced the amount of β‐sheet and increased the amount of β‐turns. From these data, it could be concluded that, in the presence of chaotropic anions, the proteins tended to prefer the β‐turn helix structure characteristic of glutenin subunits in solution. 1 H‐NMR relaxation showed that the molecules were more rigid in 1 M NaCl than in pure water, and that the mobility of the prolamins in the presence of 1 M NaCl, NaBr, and NaI increased in accordance with the position of the anions in the Hofmeister series. The increase in mobility appeared to be associated with the increase in β‐turn helical structures.