Effects of Mutating the Alanine Residue in the Consensus Pentapeptide on Biochemical and Structural Characteristics of Bacillus licheniformis Lipase
This study aimed to investigate the effect of mutating the consensus pentapeptide on the enzymatic properties and structural characteristics of Bacillus licheniformis lipase. Site-directed mutagenesis was used to construct mutants and then expressed in Escherichia coli BL21. After purification and enzyme activity analysis, only A75C and A75G retained activity. Compared to the wild-type lipase and A75G, the A75C showed higher thermostability at 40°C and better alkali resistance in pH 9.0–10.0 after incubation for 1 h. The kinetic parameters, structural characteristics and surface hydrophobicity of the lipases were determined. The results indicated that the secondary structure was hardly changed, while mutants exhibited higher activity, thermostability and hydrophobicity. Finally, the reasons for the increased enzyme activity were conducted through molecular dynamics simulation. The strategy of mutating the first residue of the lipase consensus pentapeptide may provide new insights into the enzyme engineering for industrial applications.
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