Biochemical and Molecular Characterization of Cell Wall Degrading Enzyme, Pectin Methylesterase Versus Banana Ripening: An Overview

Ripening of fruit is very important process but in some fruits, early ripening leads to a great damage during long distance transportation. There are various biochemical changes taking place during ripening such as changes in respiration, aroma, flavor, ethylene production and activity of cell wall degrading enzymes. Pectin methylesterase is one of the cell wall degrading enzymes, which acts on pectin, (a primary cell wall constituent) and releases methanol and hydrogen ions. The present compilation includes the studies on biochemical and molecular characterization of pectin methylesterase from Musa acuminata (banana). This study also deals with the in silico study reflecting inhibition of enzyme activity in context to delayed ripening in banana. It mainly deals with the identification of a PME1 gene from Grand nain variety of banana, the expression of which is related to the process of ripening. Using cross species analysis, researchers found that banana has maximum homology with carrot. The validation and verification of the designed model has been performed and found to be of good quality and further used for docking studies. Docking results suggested that green tea catechin and salicin were the best inhibitors having good interaction energies which bind at third motif, Asp381 residue on active site of PME in Musa acuminata. It was found that green tea catechin was better than salicin probably because of being a natural inhibitor, antioxidant and thus inhibiting the activity of PME. Salicin is a chemical compound that inhibits ripening at some specific concentrations only, although the binding energies of both the inhibitors have been monitored to be approximately same. The information of binding sites of ligand provides new insights into the predictable functioning of relevant protein.