scholarly journals Site-directed mutagenesis of histidine 93, aspartic acid 180, glutamic acid 205, histidine 290, and aspartic acid 291 at the active site and tryptophan 279 at the raw starch binding site in barley alpha-amylase 1.

1993 ◽  
Vol 268 (30) ◽  
pp. 22480-22484
Author(s):  
M Søgaard ◽  
A Kadziola ◽  
R Haser ◽  
B Svensson
Keyword(s):  
Glutamic Acid ◽  
Binding Site ◽  
Aspartic Acid ◽  
Active Site ◽  
Site Directed Mutagenesis ◽  
Alpha Amylase ◽  
Directed Mutagenesis ◽  
Raw Starch ◽  
Raw Starch Binding

scholarly journals Site-directed mutagenesis of dicarboxylic acids near the active site of Bacillus cereus 5/B/6 β-lactamase II

1991 ◽  
Vol 276 (2) ◽  
pp. 401-404 ◽  
Author(s):  
H M Lim ◽  
R K Iyer ◽  
J J Pène
Keyword(s):  
Bacillus Cereus ◽  
Aspartic Acid ◽  
Carboxy Group ◽  
Active Site ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
Aspartic Acid Residue ◽  
Beta Lactamase Ii

An amino acid residue functioning as a general base has been proposed to assist in the hydrolysis of beta-lactam antibiotics by the zinc-containing Bacillus cereus beta-lactamase II [Bicknell & Waley (1985) Biochemistry 24, 6876-6887]. Oligonucleotide-directed mutagenesis of cloned Bacillus cereus 5/B/6 beta-lactamase II was used in an ‘in vivo’ study to investigate the role of carboxy-group-containing amino acids near the active site of the enzyme. Substitution of asparagine for the wild-type aspartic acid residue at position 81 resulted in fully functional enzyme. An aspartic acid residue at position 90 is essential for beta-lactamase II to confer any detectable ampicillin and cephalosporin C resistance to Escherichia coli. Conversion of Asp90 into Asn90 or Glu90 lead to the synthesis of inactive enzyme, suggesting that the spatial position of the beta-carboxy group of Asp90 is critical for enzyme function.

scholarly journals Site-directed mutagenesis of active-site-related residues inTorpedoacetylcholinesterase Presence of a glutamic acid in the catalytic triad

FEBS Letters ◽  
1992 ◽  
Vol 309 (3) ◽  
pp. 421-423 ◽  
Author(s):  
Nathalie Duval ◽  
Suzanne Bon ◽  
Israel Silman ◽  
Joel Sussman ◽  
Jean Massoulié
Keyword(s):  
Glutamic Acid ◽  
Active Site ◽  
Catalytic Triad ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis

scholarly journals PEST motifs are not required for rapid calpain-mediated proteolysis of c-fos protein

1996 ◽  
Vol 313 (1) ◽  
pp. 245-251 ◽  
Author(s):  
Serge CARILLO ◽  
Magali PARIAT ◽  
Ann-Muriel STEFF ◽  
Isabelle JARIEL-ENCONTRE ◽  
Francis POULAT ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Step Process ◽  
Calcium Dependent ◽  
Fos Protein ◽  
A Cell ◽  
Intracellular Proteases

Cytoplasmic degradation of c-fos protein is extremely rapid. Under certain conditions, it is a multi-step process initiated by calcium-dependent and ATP-independent proteases called calpains. PEST motifs are peptide regions rich in proline, glutamic acid/aspartic acid and serine/threonine residues, commonly assumed to constitute built-in signals for rapid recognition by intracellular proteases and particularly by calpains. Using a cell-free degradation assay and site-directed mutagenesis, we report here that the three PEST motifs of c-fos are not required for rapid cleavage by calpains. Testing the susceptibility of PEST motif-bearing and non-bearing transcription factors including GATA1, GATA3, Myo D, c-erbA, Tal-1 and Sry, demonstrates that PEST sequences are neither necessary nor sufficient for specifying degradation of other proteins by calpains. This conclusion is strengthened by the observation that certain proteins, reportedly known to be cleavable by calpains, are devoid of PEST motifs

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