scholarly journals Site-directed mutagenesis of the beta subunit of tryptophan synthase from Salmonella typhimurium. Role of active site glutamic acid 350.

1991 ◽  
Vol 266 (12) ◽  
pp. 7618-7625
Author(s):  
A M Kayastha ◽  
Y Sawa ◽  
S Nagata ◽  
E W Miles
Keyword(s):  
Glutamic Acid ◽  
Salmonella Typhimurium ◽  
Active Site ◽  
Beta Subunit ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Tryptophan Synthase

Role of the amino acid invariants in the active site of MurG as evaluated by site-directed mutagenesis

Biochimie ◽  
2007 ◽  
Vol 89 (12) ◽  
pp. 1498-1508 ◽  
Author(s):  
Muriel Crouvoisier ◽  
Geneviève Auger ◽  
Didier Blanot ◽  
Dominique Mengin-Lecreulx
Keyword(s):  
Amino Acid ◽  
Active Site ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis

scholarly journals The mechanism of action of dd-peptidases: the role of Threonine-299 and -301 in the Streptomyces R61 dd-peptidase

1994 ◽  
Vol 301 (2) ◽  
pp. 477-483 ◽  
Author(s):  
J M Wilkin ◽  
A Dubus ◽  
B Joris ◽  
J M Frère
Keyword(s):  
Amino Acids ◽  
Active Site ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Peptide Substrate ◽  
Binding Properties ◽  
Beta Lactamases ◽  
Penicillin Binding Proteins ◽  
Active Site Cavity

The side chains of residues Thr299 and Thr301 in the Streptomyces R61 DD-peptidase have been modified by site-directed mutagenesis. These amino acids are part of a beta-strand which forms a wall of the active-site cavity. Thr299 corresponds to the second residue of the Lys-Thr(Ser)-Gly triad, highly conserved in active-site beta-lactamases and penicillin-binding proteins (PBPs). Modification of Thr301 resulted only in minor alterations of the catalytic and penicillin-binding properties of the enzyme. No selective decrease of the rate of acylation was observed for any particular class of compounds. By contrast, the loss of the hydroxy group of the residue in position 299 yielded a seriously impaired enzyme. The rates of inactivation by penicillins were decreased 30-50-fold, whereas the reactions with cephalosporins were even more affected. The efficiency of hydrolysis against the peptide substrate was also seriously decreased. More surprisingly, the mutant was completely unable to catalyse transpeptidation reactions. The conservation of an hydroxylated residue in this position in PBPs is thus easily explained by these results.

Site-directed mutagenesis of the α subunit of tryptophan synthase from salmonella typhimurium

1988 ◽  
Vol 151 (2) ◽  
pp. 672-678 ◽  
Author(s):  
Syed Ashrafuddin Ahmed ◽  
Haruhiko Kawasaki ◽  
Ronald Bauerle ◽  
Hatsué Morita ◽  
Edith Wilson Miles
Keyword(s):  
Salmonella Typhimurium ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Tryptophan Synthase ◽  
Α Subunit

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
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