Protein-tannins binding mode in hydrolyzable tannins-induced protein aggregation

Area of Science:

• Biochemistry
• Molecular Biology
• Structural Biology

Background:

• Protein-tannin interactions are complex and poorly understood, particularly in aqueous environments where protein structure is maintained.
• Elucidating these binding modes is crucial for understanding the bioactivity and sensory properties of polyphenols.

Purpose of the Study:

• To elucidate the mode of interaction between proteins and tannins using advanced computational and experimental techniques.
• To identify specific binding sites and mechanisms governing protein-tannin complex formation.

Main Methods:

• Utilized multi-molecule molecular dynamics (MD) simulations to model protein-tannin systems.
• Employed 1H15N heteronuclear single quantum coherence (HSQC) NMR spectroscopy to experimentally validate simulation findings.

Main Results:

• MD simulations revealed that tannins bind to proteins indirectly, mediated by water molecules, not through direct protein-tannin contact.
• Identified specific protein regions with high hydrogen bonding activity between water, tannins, and proteins.
• HSQC NMR chemical shift changes correlated with predicted binding sites, confirming simulation results.

Conclusions:

• The study reveals tannins bind to proteins indirectly via water bridges, clarifying a complex molecular interaction.
• Identified key protein-tannin binding sites, advancing understanding of polyphenol astringency and bioactivity.
• Provides a molecular basis for protein aggregation phenomena mediated by tannins.