101. Single-site substitutions improve cold activity and increase thermostability of the dehairing alkaline protease (DHAP)
- Author
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Li-Ying Wu, Hong-Yan Zhao, Hong Feng, and Gang Liu
- Subjects
Models, Molecular ,0301 basic medicine ,Proteases ,Protein Conformation ,Bacillus ,Peptide ,Applied Microbiology and Biotechnology ,Biochemistry ,Analytical Chemistry ,03 medical and health sciences ,Bacterial Proteins ,DHAP ,Casein ,Endopeptidases ,Enzyme Stability ,Amino Acid Sequence ,Enzyme kinetics ,Site-directed mutagenesis ,Molecular Biology ,Thermostability ,chemistry.chemical_classification ,030102 biochemistry & molecular biology ,biology ,Bacillus pumilus ,Hydrolysis ,Organic Chemistry ,Temperature ,General Medicine ,biology.organism_classification ,Kinetics ,Amino Acid Substitution ,chemistry ,Mutation ,Biotechnology - Abstract
To engineer dehairing alkaline protease (DHAP) variants to improve cold activity and increase thermostability so these variants are suitable for the leather processing industry. Based on previous studies with bacterial alkaline proteases, double-site mutations (W106K/V149I and W106K/M124L) were introduced into the DHAP from Bacillus pumilus. Compared with the wild-type DHAP hydrolytic activity, the double-site variant W106K/V149I showed an increase in specific hydrolytic activity at 15 °C by 2.3-fold toward casein in terms of hydrolytic rate and 2.7-fold toward the synthetic peptide AAPF-pN by means of kcat/Km value. The thermostability of the variant (W106K/V149I) was improved with the half-life at 60 and 70 °C increased by 2.7- and 5.0-fold, respectively, when compared with the thermostability of the wild-type DHAP. Conclusively, an increase in the cold activity and thermostability of a bacterial alkaline protease was achieved by protein engineering.
- Published
- 2016