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

Area of Science:

• Food Science and Technology
• Biochemistry
• Protein Chemistry

Background:

• Rice glutelin (RG) is a major storage protein in rice.
• Understanding protein-carbohydrate interactions is crucial for food processing and product development.

Purpose of the Study:

• To characterize the interaction between rice glutelin and amylose.
• To elucidate the binding mechanism, thermodynamic properties, and conformational changes of RG upon amylose interaction.

Main Methods:

• Spectroscopic techniques including intrinsic fluorescence, synchronous fluorescence, and circular dichroism (CD).
• Molecular docking studies for visualizing binding sites and interactions.

Main Results:

• Amylose addition increased RG intrinsic fluorescence, indicating binding.
• Binding is spontaneous and driven by hydrophobic interactions, with decreased surface hydrophobicity of RG.
• Conformational changes in RG include increased polarity around tyrosine residues, increased α-helix, and decreased β-sheet content.
• Molecular modeling identified two binding sites in the amorphous region of RG.

Conclusions:

• Rice glutelin and amylose interact spontaneously through hydrophobic forces.
• Amylose binding induces significant conformational changes in rice glutelin structure.
• The findings provide insights into the molecular basis of RG-amylose interactions relevant to rice-based food systems.