| The role of enzymes in life activities is self-evident,and the enzyme engineering is a research hotspot in biology.It is a general trend to study the structure and function of biomolecules by computer simulation.Carboxylase can catalyze the preparation of hydroxybenzoic acid and other phenolic acids using CO2as a carbon source.The laboratory has designed a green production pathway for terephthalic acid,which requires carboxylase to break through.In this paper,the following two issues have been studied through the method of calculating enzyme design:1)fitting the conversion rate of carboxylase;2)Directional modification of carboxylase and prediction of conversion rate.1)Fitting of carboxylase conversion.This article selects 2,3-DHBD＿Fo、2,3-DHBD＿Ao、2,6-DHBD＿Rs、SAD＿Tm carboxylases as research objects,and select multiple small molecules to construct a system for MD simulation.Take 30 distances,angles and dihedral angle as evaluation parameters to calculate simulation scores,and fit them with the experimental conversion rate.The R2of the fitting equation is considerable.The obtained fitting equation provides support for the directed modification of carboxylase.2)Directional modification of carboxylase and prediction of conversion rate.In order to open up a green path for the production of2-hydroxyterephthalic acid,this article uses PRODA to analyze 2,3-DHBD＿Fo for mutation design,allowing it to produce 2-hydroxyterephthalic acid using 3-hydroxybenzoic acid as the substrate and CO2as the carbon source.Nine sites around the substrate were selected for mutation design in the enzyme substrate complex structure.Multiple mutation sequences were obtained from three design schemes,and MD simulations were performed on the sequence systems to predict the mutation conversion rate by fitting equations.The W22Q/L25H/F26S/A27H/A62Y and W22N/L25H/F26S/H33M/A62Y mutants had better prediction results;The prediction results of the W22C/F26G/A62S mutant designed based on F26G were higher than those of all mutants. |
