Reference : Enzymes from Cold-Adapted Microorganisms. The Class C Beta-Lactamase from the Antarct...
Scientific journals : Article
Life sciences : Biochemistry, biophysics & molecular biology
Enzymes from Cold-Adapted Microorganisms. The Class C Beta-Lactamase from the Antarctic Psychrophile Psychrobacter Immobilis A5
Feller, Georges mailto [Université de Liège - ULg > Département des sciences de la vie > Labo de biochimie >]
Zekhnini, Z. [> > > >]
Lamotte-Brasseur, J. [> > > >]
Gerday, Charles mailto [Université de Liège - ULg > Services généraux (Faculté des sciences) > Relations académiques et scientifiques (Sciences) >]
European Journal of Biochemistry
Yes (verified by ORBi)
[en] A heat-labile beta-lactamase has been purified from culture supernatants of Psychrobacter immobilis A5 grown at 4 degrees C and the corresponding chromosomal ampC gene has been cloned and sequenced. All structural and kinetic properties clearly relate this enzyme to class C beta-lactamases. The kinetic parameters of P. immobilis beta-lactamase for the hydrolysis of some beta-lactam antibiotics are in the same range as the values recorded for the highly specialized cephalosporinases from pathogenic mesophilic bacteria. By contrast, the enzyme displays a low apparent optimum temperature of activity and a reduced thermal stability. Structural factors responsible for the latter property were analysed from the three-dimensional structure built by homology modelling. The deletion of proline residues in loops, the low number of arginine-mediated H-bonds and aromatic-aromatic interactions, the lower global hydrophobicity and the improved solvent interactions through additional surface acidic residues appear to be the main determinants of the enzyme flexibility.

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