Understanding the Molecular Basis for Enhanced Glutenase Activity of Actinidin using Structural Bioinformatics

Background: Management of gluten intolerance is currently possible only by consumption of a gluten-free diet (GFD) for a lifetime. The scientific community has been searching for alternatives to GFD, like the inclusion of natural proteases with meals or pre-treatment of gluten-containing foods with glutenases. Actinidin from kiwifruit has shown considerable promise in digesting immunogenic gliadin peptides compared to other plant-derived cysteine proteases. Methods: In this study, we aimed to understand the structural basis for the elevated protease action of actinidin against gliadin peptides by using an in silico approach. Results: Docking experiments revealed key differences between the binding of gliadin peptide to actinidin and papain, which may be responsible for their differential digestive action. Conclusion: Sequence comparison of different plant cysteine proteases highlights amino acid residues surrounding the active site pocket of actinidin that are unique to this molecule and hence likely to contribute to its digestive properties.