Avocado Fruit Defensin (PaDef) Promote Trypsin and Chymotrypsin Enzyme Activity: A Computational Approach

The fruit ripening process affects the nutritional content and quality. Many fruit species have become more acceptable and present high nutritional value for animal consumption. The avocado is a fruit that produces various compounds of great significance to human nutrition, including peptides crucial to innate immunity. Avocado defensin (PaDef) is an antimicrobial peptide produced during the fruit ripening stage. Defensins have been reported to present antimicrobial activity and act as serin protease inhibitors. However, the present study found that PaDef enhanced the activity of serine proteases (which are digestive enzymes) such as trypsin and chymotrypsin, which is a new finding on the functions of plant defensin. Via the use of molecular docking assessments, the present study found that specific PaDef fragments primarily bind to the active sites of trypsin and chymotrypsin. Moreover, the stability and behavior of the peptides generated in silico from PaDef were evaluated in the presence of chymotrypsin A protease digestion using molecular dynamics simulations under basic conditions. The results obtained suggest that the selective fragments of PaDef peptides induce enzyme activity via allosteric modulation, an area of increasing research interest due to its implications for both fundamental biochemistry and applied biotechnology. The present study is a novel report on the activity of a plant defensin at a molecular level.