ISSN:
1572-8951
Keywords:
Bacillus stearothermophilus α-amylase
;
catalytic residues
;
site-directed mutagenesis
;
structure-function studies
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Putative catalytic residues of the thermostable Bacillus stearothermophilus α-amylase derived by sequence analysis and computer modeling were tested by site-directed mutagenesis. The conservative mutations produced were Asp-234-Glu, Glu-264-Asp, and Asp-331-Asn. The corresponding amino acids have been proposed to act in acid-base catalysis in the Aspergillus oryzae and porcine pancreatic α-amylase. Isoelectric focusing and immunodiffusion studies showed that, although inactive, the mutant proteins have conformations similar to the wild type enzyme. The cause of inactivation is presumably a steric clash or alteration of a catalytic amino acid in the case of Asp-234-Glu and a mutation of a catalytic residue in the mutants Glu-264-Asp and Asp-331-Asn.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00161668
Permalink
