Open Access Short Report

Seed storage proteins of the globulin family are cleaved post-translationally in wheat embryos

Adam G Koziol1, Evelin Loit1,2, Melissa McNulty1,3, Amanda J MacFarlane1,4,5, Fraser W Scott1,4 and Illimar Altosaar1*

Author Affiliations

1 Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, K1H 8M5, Canada

2 Present address: Department of Field Crops and Grassland Husbandry, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu, 51014, Estonia

3 Present address: Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, 55905, USA

4 Ottawa Hospital Research Institute, Ottawa, Ontario, K1H 8L6, Canada

5 Present address: Nutrition Research Division, Food Directorate, Health Canada, Ottawa, Ontario, K1A 0K9, Canada

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BMC Research Notes 2012, 5:385 doi:10.1186/1756-0500-5-385

Published: 28 July 2012

Abstract

Background

The 7S globulins are plant seed storage proteins that have been associated with the development of a number of human diseases, including peanut allergy. Immune reactivity to the wheat seed storage protein globulin-3 (Glo-3) has been associated with the development of the autoimmune disease type 1 diabetes in diabetes-prone rats and mice, as well as in a subset of human patients.

Findings

The present study characterized native wheat Glo-3 in salt-soluble wheat seed protein extracts. Glo-3-like peptides were observed primarily in the wheat embryo. Glo-3-like proteins varied significantly in their molecular masses and isoelectric points, as determined by two dimensional electrophoresis and immunoblotting with anti-Glo-3A antibodies. Five major polypeptide spots were identified by mass spectrometry and N-terminal sequencing as belonging to the Glo-3 family.

Conclusions

These results in combination with our previous findings have allowed for the development of a hypothetical model of the post-translational events contributing to the wheat 7S globulin profile in mature wheat kernels.

Keywords:
Globulin 3; Type 1 diabetes; Vicilin; Wheat; Allergies; Post-translational processing; Mass spectrometry; Seed storage protein; Celiac disease