Improving Sensitivity of Enzyme to Organophosphorous Compounds by Combining Experiment and Theory Methods

In this paper,we compared the sensitivities of AFEST（a thermophilic esterase from the archaea Archaeoglobus fulgidus） and acetylcholinesterase（AChE） towards five organophosphorus compounds（OPs） by means of molecular docking,and found that only the docking energy between AFEST and dichlorvos is lower than that between AChE and dichlorvos.Via the docking model of AFEST and dichlorvos,Arg43 was found to play an important role in the interaction between AFEST and dichlorvos by means of stabilizing the complex.Then mutant R43S was constructed,the IC 50（the concentration required to reduce virus-induced cytopathicity by 50% is estimated as 50% inhibitory concentration） of which to dichlorvos was lower than that of the wild type AFEST by a factor of 1.56,indicating the enhanced sensitivity of mutant R43S to dichlorvos.Combining of theory with experiment,we have obtained important structure-function information of AFEST,which will be helpful to the further studies of esterase.

Insight into Substrate Preference of Two Chimeric Esterases by Combining Experiment and Molecular Simulation

Better understanding of the relationship between the substrate preference and structural module of esterases is helpful to novel enzyme development. For this purpose, two chimeric esterases AAM7 and PAR, constructed via domain swapping between two ancient thermophilic esterases, were investigated on their molecular simulation（including homology modeling, substrates docking and substrate binding affinity validation） and enzymatic assay（specific activities and activation energies calculating）. Our results indicate that the factors contributing to the substrate preference of many enzymes especially the broad-specificity enzymes like esterases are multiple and complicated, the substrate binding domains or binding pockets are important but not the only factor for substrate preference.