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Title: Structure, Morphology, and Assembly Behavior of Kafirin

Abstract

Prolamins from grains have attracted intensive attention in recent years due to their potential in satisfying the demand for environmentally friendly (biodegradable), abundantly available (sustainable), and cost-effective biomaterials. However, for kafirin, the prolamin from sorghum, its composition, structure, morphology, and self-assembly behaviors have not been fully characterized. In this paper, kafirin was extracted from the whole sorghum grain and found to contain 68, 14, 6, and 12% of α-, β-, and γ-fractions and cross-linked kafirin, respectively. Freeze-dried kafirin contained ~49% α-helix in the solid state. When dissolved in 65% (v/v) isopropanol, 60% (v/v) tert-butanol, and 85% (v/v) ethanol aqueous solvents, the relative α-helix content in kafirin increased with the decrease of solvent polarity. Structural analysis using small-angle X-ray scattering (SAXS) indicated that kafirin (2 mg/mL) took stretched and extended conformations with dimensions of 118 × 15 × 15 and 100 × 11 × 11 Å in 60% tert-butanol and 65% isopropanol, respectively. More elongated conformation of individual kafirin with high-order assembly was observed in 85% ethanol. Protein aggregation occurred as protein concentration increased in its good solvent. The morphology of kafirin assemblies captured by atomic force microscopy (AFM) revealed that kafirin protein took uniform particle morphology at low concentration, andmore » disk-like or rod-like structures resulting from solvent evaporation induced particle interactions emerged at high concentrations. These results suggest that both protein concentration and solvent polarity can effectively regulate kafirin assemblies from thick rod-like to slim rod-like structures, a convenient way to tune the fibrillation of prolamin-based biomaterials.« less

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1351364
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Agricultural and Food Chemistry; Journal Volume: 63; Journal Issue: 1
Country of Publication:
United States
Language:
ENGLISH
Subject:
60 APPLIED LIFE SCIENCES

Citation Formats

Xiao, Jie, Li, Yunqi, Li, Ji, Gonzalez, Alejandro Perez, Xia, Qiuyang, and Huang, Qingrong. Structure, Morphology, and Assembly Behavior of Kafirin. United States: N. p., 2015. Web. doi:10.1021/jf504674z.
Xiao, Jie, Li, Yunqi, Li, Ji, Gonzalez, Alejandro Perez, Xia, Qiuyang, & Huang, Qingrong. Structure, Morphology, and Assembly Behavior of Kafirin. United States. doi:10.1021/jf504674z.
Xiao, Jie, Li, Yunqi, Li, Ji, Gonzalez, Alejandro Perez, Xia, Qiuyang, and Huang, Qingrong. Wed . "Structure, Morphology, and Assembly Behavior of Kafirin". United States. doi:10.1021/jf504674z.
@article{osti_1351364,
title = {Structure, Morphology, and Assembly Behavior of Kafirin},
author = {Xiao, Jie and Li, Yunqi and Li, Ji and Gonzalez, Alejandro Perez and Xia, Qiuyang and Huang, Qingrong},
abstractNote = {Prolamins from grains have attracted intensive attention in recent years due to their potential in satisfying the demand for environmentally friendly (biodegradable), abundantly available (sustainable), and cost-effective biomaterials. However, for kafirin, the prolamin from sorghum, its composition, structure, morphology, and self-assembly behaviors have not been fully characterized. In this paper, kafirin was extracted from the whole sorghum grain and found to contain 68, 14, 6, and 12% of α-, β-, and γ-fractions and cross-linked kafirin, respectively. Freeze-dried kafirin contained ~49% α-helix in the solid state. When dissolved in 65% (v/v) isopropanol, 60% (v/v) tert-butanol, and 85% (v/v) ethanol aqueous solvents, the relative α-helix content in kafirin increased with the decrease of solvent polarity. Structural analysis using small-angle X-ray scattering (SAXS) indicated that kafirin (2 mg/mL) took stretched and extended conformations with dimensions of 118 × 15 × 15 and 100 × 11 × 11 Å in 60% tert-butanol and 65% isopropanol, respectively. More elongated conformation of individual kafirin with high-order assembly was observed in 85% ethanol. Protein aggregation occurred as protein concentration increased in its good solvent. The morphology of kafirin assemblies captured by atomic force microscopy (AFM) revealed that kafirin protein took uniform particle morphology at low concentration, and disk-like or rod-like structures resulting from solvent evaporation induced particle interactions emerged at high concentrations. These results suggest that both protein concentration and solvent polarity can effectively regulate kafirin assemblies from thick rod-like to slim rod-like structures, a convenient way to tune the fibrillation of prolamin-based biomaterials.},
doi = {10.1021/jf504674z},
journal = {Journal of Agricultural and Food Chemistry},
number = 1,
volume = 63,
place = {United States},
year = {Wed Jan 14 00:00:00 EST 2015},
month = {Wed Jan 14 00:00:00 EST 2015}
}