Enhancing Thermostability of Aminopeptidase by Improving the Hydrophobic Interactions in the Substrate Binding Region

Abstract:

The increase of thermostability of aminopeptidase by creating hydrophobic interactions in the substrate binding region was exploited in Bacillus subtilis 168. The hydrophilic residue N385 was targeted and substituted by hydrophobic residue L385. Based on thermostability analysis，N385L mutant was found to retain 20% while the relative activity of the wild type was reduced to 0% at the same temperature（80 ℃）in 30 min. Furthermore，the affinity and catalytic efficiency of the mutant N385L for the subtrate of L-Leu-pNA increased by 47.4% and 28.5%，respectively，compared to wild type. This study will inspire the production of thermostable aminopeptidase for industrial application.