Binding interaction between rice glutelin and amylose: Hydrophobic interaction and conformational changes

Published Date

November 2015, Vol.81:942–950, doi:10.1016/j.ijbiomac.2015.09.041

Title 

Binding interaction between rice glutelin and amylose: Hydrophobic interaction and conformational changes

• Author 

• Xingfeng Xu ^a
• Wei Liu ^a,,
• Junzhen Zhong ^a
• Liping Luo ^a
• Chengmei Liu ^a,,
• Shunjing Luo ^a
• Lin Chen ^b

• aState Key Laboratory of Food Science and Technology, Nanchang University, No. 235 Nanjing East Road, Nanchang 330047, Jiangxi, China
• bGolden Agriculture Biotech Company Limited, No. 100 Xinzhou Road, Nanchang 330000, Jiangxi, China

Received 4 May 2015. Revised 22 September 2015. Accepted 23 September 2015. Available online 28 September 2015.

Highlights

• •
  The intermolecular interaction in glutelin–amylose mixed system was investigated.
• •
  Hydrophobic interaction was the predominant binding force in the binding process.
• •
  Surface hydrophobicity of glutelin decreased in the presence of amylose.
• •
  The conformational changes were studied in glutelin–amylose mixed system.
• •
  Binding sites located in the amorphous area were presented by molecular modeling.

Abstract

The interaction of rice glutelin (RG) with amylose was characterized by spectroscopic and molecular docking studies. The intrinsic fluorescence of RG increased upon the addition of amylose. The binding sites, binding constant and thermodynamic features indicated that binding process was spontaneous and the main driving force of the interaction was hydrophobic interaction. The surface hydrophobicity of RG decreased with increasing amount of amylose. Furthermore, synchronous fluorescence and circular dichroism (CD) spectra provided data concerning conformational and micro-environmental changes of RG. With the concentration of amylose increasing, the polarity around the tyrosine residues increased while the hydrophobicity decreased. Alteration of protein conformation was observed with increasing of α-helix and reducing of β-sheet. Finally, a visual representation of two binding sites located in the amorphous area of RG was presented by molecular modeling studies.

Keywords

• Rice glutelin
• Amylose
• Hydrophobic interaction
• Conformation
• Molecular modeling

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• ⁎ 
  Corresponding author.

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