Wheat glutenin proteins assemble into a nanostructure with unusual structural features

Mackintosh, S.H., Meade, S.J., Healy, J.P., Sutton, K.H., Larsen, N.G., Squires, A.M. and Gerrard, J.A. (2009) Wheat glutenin proteins assemble into a nanostructure with unusual structural features. Journal of Cereal Science, 49 (1). pp. 157-162. ISSN 0733-5210 doi: 10.1016/j.jcs.2008.08.003

Abstract/Summary

The proteins of wheat have a known propensity to aggregate into a variety of forms. We report here a novel nanostructure from wheat proteins, derived from a crude extract of high molecular weight glutenins. The structure was characterised by a significant thioflavin T (ThT) fluorescence and a fibrillar morphology by transmission electron microscopy (TEM). The ThT fluorescence and TEM data are suggestive of an amyloid structure, but the X-ray fibre diffraction data show a reflection pattern (4.02, 4.2-4.3, 4.6, 12.9,19.3 and 38.7 angstrom) inconsistent with both the classic amyloid form and the previously described beta-helix structure. The 4.6 angstrom reflection is consistent with that predicted for the amyloid inter-beta-strand, and the absence of the inter-beta-sheet distance at approximate to 10-11 angstrom is not unprecedented in amyloid-like structures. However, our observed X-ray reflection pattern has not been previously reported and suggests a novel wheat glutenin nanostructure. (C) 2008 Elsevier Ltd. All rights reserved.