FT-Raman Spectroscopy as a Tool to Study the Secondary Structures of Wheat Gliadin Proteins |
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Authors: | Iwona Stawoska Aleksandra Weseucha-Birczyska Andrzej Skoczowski Micha Dziurka Jacek Waga |
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Institution: | 1.Institute of Biology, Pedagogical University of Krakow, Podchorążych 2, 30-084 Krakow, Poland;2.Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland;3.The Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Niezapominajek 21, 30-239 Krakow, Poland;4.Department of Physiology, Plant Breeding and Seed Science, University of Agriculture, Podłużna 3, 30-239 Kraków, Poland |
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Abstract: | Raman spectroscopy is a useful method in biological, biomedical, food, and agricultural studies, allowing the simultaneous examination of various chemical compounds and evaluation of molecular changes occurring in tested objects. The purpose of our research was to explain how the elimination of ω-fractions from the wheat gliadin complex influences the secondary structures of the remaining αβγ-gliadins. To this aim, we analyzed the endosperm of wheat kernels as well as gliadin proteins extracted from two winter wheat genotypes: wasko.gl+ (control genotype containing the full set of gliadins) and wasko.gl− (modified genotype lacking all ω-gliadins). Based on the decomposition of the amide I band, we observed a moderate increase in β-forms (sheets and turns) at the expense of α-helical and random coil structures for gliadins isolated from the flour of the wasko.gl− line. Since ω-gliadins contain no cysteine residues, they do not participate in the formation of the disulfide bridges that stabilize the protein structure. However, they can interact with other proteins via weak, low-energetic hydrogen bonds. We conclude that the elimination of ω-fractions from the gliadin complex causes minor modifications in secondary structures of the remaining gliadin proteins. In our opinion, these small, structural changes of proteins may lead to alterations in gliadin allergenicity. |
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Keywords: | gluten proteins gliadins amide I secondary structure Raman spectroscopy |
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