title: [Enhancement of enzyme activity and thermostability of N-acylhomoserine lactonase by site-directed mutagenesis].
abstract: 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.
  
  
  CONCLUSIONS
  Molecular modulation by site-directed mutagenesis could significantly improve enzymatic activity and thermostability of AiiA.
authors.forename: Mei
authors.initials: M
authors.lastname: Yang
authors.forename: Panpan
authors.initials: P
authors.lastname: Xie
authors.forename: Simei
authors.initials: S
authors.lastname: Jian
authors.forename: Liyu
authors.initials: L
authors.lastname: Lin
authors.forename: Caiyun
authors.initials: C
authors.lastname: Yang
mesh_terms: D000595:Amino Acid Sequence; D001413:Bacillus thuringiensis / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D003001:Cloning, Molecular; D004795:Enzyme Stability; D006358:Hot Temperature; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D002265:Carboxylic Ester Hydrolases; C432003:N-acyl homoserine lactonase