Reference : Site-Directed Mutagenesis of the Streptomyces R61 Dd-Peptidase. Catalytic Function of th...
Scientific journals : Article
Life sciences : Microbiology
http://hdl.handle.net/2268/5960
Site-Directed Mutagenesis of the Streptomyces R61 Dd-Peptidase. Catalytic Function of the Conserved Residues around the Active Site and a Comparison with Class-a and Class-C Beta-Lactamases
[en] The importance of various residues in the Streptomyces R61 penicillin-sensitive DD-peptidase has been assessed by site-directed mutagenesis. The replacement of the active Ser62 by a Cys residue yielded an inactive protein which was also unable to recognize penicillin. The activity of the Lys65----Arg mutant with the peptide and thiolester substrates was decreased 100-200-fold and the rate of penicillin inactivation was decreased 20,000-fold or more. The mutant thus behaved as a poor, but penicillin-resistant, DD-peptidase. The other studied mutations, the mutations Phe58----Leu, Tyr90----Asn, Thr101----Asn, Phe164----Ala, Asp225----Glu and Asp225----Asn had little influence on the catalytic and penicillin-binding properties. The Asp225 mutants did not exhibit an increased sensitivity to cefotaxime. The Phe164----Ala mutant was significantly more unstable than the wild-type enzyme.
[Université de Liège - ULg > > Centre d'ingénierie des protéines >]
