In silico screening of 393 mutants facilitates enzyme engineering of amidase activity in CalB

TL;DR

This study benchmarks a computational screening method for predicting enzyme activity in CalB mutants, successfully identifying highly active mutants and proposing new candidates for enzyme engineering.

Contribution

It validates a high throughput computational screening approach for enzyme mutants and applies it to identify promising CalB mutants for enhanced amidase activity.

Findings

Qualitative activity predicted for 15 of 22 mutants

Four of six most active mutants identified

At least 20 new promising mutants proposed

Abstract

Our previously presented method for high throughput computational screening of mutant activity (Hediger et al., arXiv:1203.2950) is benchmarked against experimentally measured amidase activity for 22 mutants of Candida antarctica lipase B (CalB). Using an appropriate cutoff criterion for the computed barriers, the qualitative activity of 15 out of 22 mutants is correctly predicted. The method identifies four of the six most active mutants with >=3-fold wild type activity and seven out of the eight least active mutants with <=0.5-fold wild type activity. The method is further used to screen all sterically possible (386) double-, triple- and quadruple-mutants constructed from the most active single mutants. Based on the benchmark test at least 20 new promising mutants are identified.