Mechanism Of PMEI Inhibiting PME And Modification Of Food Application PMEI

Fruit and vegetable juice is a kind of mixed product made from fruit or vegetables,which is widely praised by consumers because of its high nutritional value and unique flavor.The stable presence of turbid state can give fruit and vegetable juice a good appearance and taste.However,the endogenous PME in fruit juice can hydrolyze the methylester group in pectin,reduce the esterification degree of pectin,and destroy the stable turbidity state of fruit juice.The activity of PME is regulated by a variety of factors,among which PMEI can specifically bind to and inhibit the activity of PME,which together determine the degree of deesterification of pectin.PMEI not only plays an important role in fruit and vegetable processing,but also has broad application prospects in plant disease and insect pest control.In this paper,the processing methods and physicochemical properties of fruit and vegetable juices,the gene family,crystal structure,mechanism of action of PME and PMEI,and their roles in plants and industry were reviewed.Then,the molecular recognition and conformational change of PME and PMEI were analyzed by various molecular simulation methods.Suggestions to improve the thermal stability and affinity maturation of PMEI were made by semi-rational design.The phylogenetic tree results show that PME and PMEI have good sequence and structural conservation in a variety of plants,and the simulated data can be widely adopted.Protein interaction analysis showed that hydrogen bonds,van der Waals forces and the salt bridge formed by K224 and _ID116 were the main driving forces for the mutual molecular recognition of PME and PMEI.Based on free energy landscape(FEL),conformational clustering,and motion analysis,binding to PMEI greatly disrupted the dispersed functional movement patterns and biological functions of PME.The _IG35M/_IG35R:_IT93F and _IT113W/_IT113W:_ID116W mutations contribute to the thermal stability and affinity maturation of the PMEI,respectively,by monitoring changes in the number of residue contacts and binding free energy.This work reveals the interaction between PME and PMEI at the gene and protein levels,provides a possible option for modifying specific PMEI,and has important guiding significance for the development of fruit and vegetable juice processing industry.