scholarly journals Studies on the reaction mechanism of a microbial lipase/acyltransferase using chemical modification and site-directed mutagenesis.

1991 ◽  
Vol 266 (2) ◽  
pp. 997-1000 ◽  
Author(s):  
S Hilton ◽  
J T Buckley
Keyword(s):  
Reaction Mechanism ◽  
Chemical Modification ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Microbial Lipase

Structure-Function Studies of Escherichia coli Biotin Synthase via a Chemical Modification and Site-Directed Mutagenesis Approach

2001 ◽  
Vol 130 (5) ◽  
pp. 627-635 ◽  
Author(s):  
L. Farh ◽  
S.-Y. Hwang ◽  
L. Steinrauf ◽  
H.-J. Chiang ◽  
D. Shiuan
Keyword(s):  
Escherichia Coli ◽  
Chemical Modification ◽  
Structure Function ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Biotin Synthase

scholarly journals Site-directed mutagenesis at aspartate and glutamate residues of xylanase from Bacillus pumilus

1992 ◽  
Vol 288 (1) ◽  
pp. 117-121 ◽  
Author(s):  
E P Ko ◽  
H Akatsuka ◽  
H Moriyama ◽  
A Shinmyo ◽  
Y Hata ◽  
...  
Keyword(s):  
Amino Acids ◽  
Reaction Mechanism ◽  
Amino Acid ◽  
Bacillus Pumilus ◽  
Specific Activity ◽  
Sequence Similarity ◽  
Site Directed Mutagenesis ◽  
Dimensional Structure ◽  
Amino Acid Sequence Similarity ◽  
Directed Mutagenesis

To elucidate the reaction mechanism of xylanase, the identification of amino acids essential for its catalysis is of importance. Studies have indicated the possibility that the reaction mechanism of xylanase is similar to that of hen's egg lysozyme, which involves acidic amino acid residues. On the basis of this assumption, together with the three-dimensional structure of Bacillus pumilus xylanase and its amino acid sequence similarity to other xylanases of different origins, three acidic amino acids, namely Asp-21, Glu-93 and Glu-182, were selected for site-directed mutagenesis. The Asp residue was altered to either Ser or Glu, and the Glu residues to Ser or Asp. The purified mutant xylanases D21E, D21S, E93D, E93S, E182D and E182S showed single protein bands of about 26 kDa on SDS/PAGE. C.d. spectra of these mutant enzymes show no effect on the secondary structure of xylanase, except that of D21E, which shows a little variation. Furthermore, mutations of Glu-93 and Glu-182 resulted in a drastic decrease in the specific activity of xylanase as compared with mutation of Asp-21. On the basis of these results we propose that Glu-93 and Glu-182 are the best candidates for the essential catalytic residues of xylanase.

Controlled Site-Selective Glycosylation of Proteins by a Combined Site-Directed Mutagenesis and Chemical Modification Approach

1998 ◽  
Vol 63 (26) ◽  
pp. 9614-9615 ◽  
Author(s):  
Benjamin G. Davis ◽  
Richard C. Lloyd ◽  
J. Bryan Jones
Keyword(s):  
Chemical Modification ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Site Selective
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