OBJECTIVE: To enhance enzymatic activity and thermostability of N-acylhomoserine lactonase (AiiA). METHODS: We performed site-directed mutagenesis based on AiiA homologous 3-D protein structure, and analyzed enzymatic activity and thermostability of both wild type and mutated AiiA. RESULTS: The wild type AiiA lost its N-acylhomoserine lactone (AHL) degrading activity after being incubated at 45 degrees C for 30 min or after being stored at 4 degrees C for 5 days. By comparison, the AHL-degrading activities of three types of mutated AiiA (N65K, T195R, and A206E) were enhanced, and their storage periods at 4 degrees C were extended to 7 days. In addition, the N65K mutant acquired higher temperature tolerance with remain of more than 45% of its enzymatic activity after being incubated at 45 degrees C and 5.0% enzymatic activity after being incubated at 55 degrees C as compared to the wild type. CONCLUSION: Molecular modulation by site-directed mutagenesis could significantly improve enzymatic activity and thermostability of AiiA.
OBJECTIVE: To enhance enzymatic activity and thermostability of N-acylhomoserine lactonase (AiiA). METHODS: We performed site-directed mutagenesis based on AiiA homologous 3-D protein structure, and analyzed enzymatic activity and thermostability of both wild type and mutated AiiA. RESULTS: The wild type AiiA lost its N-acylhomoserine lactone (AHL) degrading activity after being incubated at 45 degrees C for 30 min or after being stored at 4 degrees C for 5 days. By comparison, the AHL-degrading activities of three types of mutated AiiA (N65K, T195R, and A206E) were enhanced, and their storage periods at 4 degrees C were extended to 7 days. In addition, the N65K mutant acquired higher temperature tolerance with remain of more than 45% of its enzymatic activity after being incubated at 45 degrees C and 5.0% enzymatic activity after being incubated at 55 degrees C as compared to the wild type. CONCLUSION: Molecular modulation by site-directed mutagenesis could significantly improve enzymatic activity and thermostability of AiiA.