Role of Acidic and Aromatic Amino Acids inRhodobacter CapsulatusCytochromec1. A Site-Directed Mutagenesis Study†

Biochemistry ◽  
2003 ◽  
Vol 42 (29) ◽  
pp. 8818-8830 ◽  
Author(s):  
Jun Li ◽  
Artur Osyczka ◽  
Richard C. Conover ◽  
Michael K. Johnson ◽  
Hong Qin ◽  
...  
Keyword(s):  
Amino Acids ◽  
Aromatic Amino Acids ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
A Site ◽  
Mutagenesis Study

The Role of Residues 103, 104, and 278 in the Activity of SMG1 Lipase from Malassezia globosa: A Site-Directed Mutagenesis Study

2015 ◽  
Vol 25 (11) ◽  
pp. 1827-1834 ◽  
Author(s):  
Dongming Lan ◽  
Qian Wang ◽  
Grzegorz Maria Popowicz ◽  
Bo Yang ◽  
Qingyun Tang ◽  
...  
Keyword(s):  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Malassezia Globosa ◽  
A Site ◽  
Mutagenesis Study

scholarly journals A site-directed mutagenesis study of human placental aromatase.

1992 ◽  
Vol 267 (2) ◽  
pp. 762-768
Author(s):  
D J Zhou ◽  
K R Korzekwa ◽  
T Poulos ◽  
S A Chen
Keyword(s):  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
A Site ◽  
Mutagenesis Study

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.

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