Enzymes from Cold-Adapted Microorganisms. The Class C Beta-Lactamase from the Antarctic Psychrophile Psychrobacter Immobilis A5
peer reviewed 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-lactam...
| Published in: | European Journal of Biochemistry |
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| Main Authors: | , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Blackwell
1997
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| Subjects: | |
| Online Access: | https://orbi.uliege.be/handle/2268/16260 https://orbi.uliege.be/bitstream/2268/16260/1/EJB_1997_betalact.pdf https://doi.org/10.1111/j.1432-1033.1997.00186.x |
| Summary: | peer reviewed 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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