Quantitative Structure‐Function Relationships of the Single‐Point Mutants of Haloalkane Dehalogenase: A Multivariate Approach

The applicability of multivariate statistical methods for the systematic analysis of results from the site‐directed experiments was tested. Dehalogenation data obtained with 15 single‐point mutants of haloalkane dehalogenase of Xanthobacter autotrophicus GJ10 has been related to various physico‐chemical properties of substituted amino acids. A two component model which explains 84% of activity data was derived. The most influential properties, required on position 172 in haloalkane dehalogenase were: aromaticity, main‐chain flexibility, refractivity and bulkiness, and were related mainly to the transition state/halide stabilization. The general usage of multivariate techniques for quantitative structure‐function relationships (QSFR) and protein engineering studies can be recommended. Score and loading plots from Principal Component Analysis (PCA) of physico‐chemical properties of amino acids can be used for planning and design of site‐directed mutagenesis experiments, while the models obtained from Projection to Latent Structures (PLS) can provide predictions on the effect of the mutations on protein functionality prior to its testing.