SNIC SUPR
Validating the structure of gluten proteins
Dnr:

SNIC 2018/3-567

Type:

SNIC Medium Compute

Principal Investigator:

Mikael Hedenqvist

Affiliation:

Kungliga Tekniska högskolan

Start Date:

2018-12-01

End Date:

2019-12-01

Primary Classification:

10406: Polymer Chemistry

Secondary Classification:

10403: Materials Chemistry

Tertiary Classification:

10304: Condensed Matter Physics

Webpage:

Allocation

Abstract

The gluten proteins α-gliadin and LMW-glutenin, with properties interesting for industrial applications, differ noteworthy in one aspect -their ability to polymerize. Both proteins are composed of similar building blocks with repetitive regions of amino acid sequences and have the components necessary to polymerize. Additional both are intrinsically disordered and therefore lack structures, still only the LMW-glutenins are capable to polymerize in-vivo. The LMW-glutenins polymerize with other glutenin proteins in the wheat seed by forming covalent bonds between cysteine residues, meanwhile the α-gliadins appear as single molecules. The proteins are of industrial interest, especially within material and food industry, due to their different elasticity and viscosity properties. Especially the Gliadin proteins possess unique film forming properties similar to those of petroleum based low density polypropylene materials. We know that when gliadin proteins are modified with additives and molded at a high temperature, they show hierarchical arrangements in the form of hexagonal nano-structures. The polymerization frequency among the proteins, impact the quality of wheat flour. With knowledge of the polymerization process, it can lead to altered agricultural practices towards higher quality of wheat grain yield. Our recent results, obtained in our outgoing SNIC allocation indicate what protein properties that explain the molecular behavior in terms of the tendency of the proteins to self-associate or polymerize. We currently work with two manuscripts explaining the self-association behavior of α-gliadin, and the reason why LMW-glutenins are monomeric, which need a continuation of current allocation. These data were obtained through Monte Carlo simulations, introducing disulphide bonds between cysteines within the proteins and exposing the proteins to a crowded environment. With a continuation of current project we will be able to continue to unravel further the molecular background of the behavior of these proteins. In order to validate the simulations we have already obtained experimental data on the proteins from samples analyzed with HPLC, FT-IR, SAXS, WAXS and Tensile methods. We have pure samples of α-gliadin available, and have experimental data on it from Light scattering, Circular dichroism and Infra-red scattering. Next step in the project is to evaluate the effects of chaperons and other additives on the proteins. The introduction of these components will effect both the chemical structure of the protein and the environment surrounding it. We will investigate the proteins behavior both from a biological and a material point of view. The first two chemical chaperones planned to be evaluated are “BiP” and “Glycerol”. BiP is present in the wheat seed contributing to native protein folding. Glycerol is contributing to fold the α-gliadin into supramolecular hexagonal structure. By the use of simulations we hope to extract kinetic data, possibly explaining protein folding, and structural data to understand and describe potential material properties. A continuation of current allocation is necessary to finalize current manuscripts and continue the project toward upcoming planed simulation experiments. We find a allocation matching current one as sufficient for the tasks at hand, and a continuation will suffice.