Analysis of the reaction mechanism and substrate specificity of haloalkane dehalogenases by sequential and structural comparisons

摘要: Haloalkane dehalogenases catalyse environmentally important dehalogenation reactions. These microbial enzymes represent objects of interest for protein engineering studies, attempting to improve their catalytic efficiency or broaden substrate specificity towards environmental pollutants. This paper presents the results a comparative study haloalkane originating from different organisms. Protein sequences and models tertiary structures were compared investigate fold, reaction mechanism these enzymes. contain structural motifs alpha/beta-hydrolases epoxidases within sequences. They triad with two topological arrangements. The presence structurally conserved oxyanion hole suggests two-step previously described dehalogenase Xanthobacter autotrophicus GJ10. differences in species might be related size geometry an active site its entrance transition state halide ion stabilization by residues. Structurally identified can used design specific primers experimental screening dehalogenases. Those amino acids which predicted functionally possible targets future site-directed mutagenesis experiments.