Exploring the impact of 1-deoxynojirimycin on alpha-galactosidase activity and chickpea seed germination through in vitro experiments and molecular docking analysis

ABSTRACT:

Seed germination is a tightly regulated physiological process. Hydrolytic enzymes provide energy that brings physiological, biochemical, and physical changes to the seed during germination. Alpha-galactosidases break down alpha 1-6 linked galactosyl groups in glycoproteins, glycolipids, and oligosaccharides into simple compounds to provide energy during seed germination. Chickpea seed germination characteristics showed that inhibition of alpha-galactosidase using 1-deoxynojirimycin (DNJ), a derivative of deoxygalactonojirimycin, delays germination. To gain insights into the mechanism of inhibition, we modeled the enzyme’s structure and performed in-silico docking of the inhibitor and natural substrates (raffinose and stachyose) to the enzyme. We also validated our model using recombinant chickpea alpha-galactosidase. Our docking studies showed that both the inhibitor and the substrates bind to the same active site pocket in the enzyme but to different amino acid residues, stachyose being a preferred substrate, and DNJ competitively inhibits alpha-galactosidase with a Ki and IC50 of 44.5 µM and 89.13 µM respectively. Delayed germination is a desirable agronomic practice that can be explored for better crop establishment and to prevent pre-harvest sprouting in crops.

Index terms:
1-deoxynojirimycin; alpha-galactosidase; germination; inhibition kinetics