BETA-LACTAMASE OF LYSOBACTER-ENZYMOGENES - CLONING, CHARACTERIZATION AND EXPRESSION OF THE GENE AND COMPARISON OF THE ENZYME TO OTHER LACTAMASES

The gene for the periplasmic beta-lactamase of Lysobacter enzymogenes was isolated as part of a 1017 bp EcoRI fragment and the nucleotide se quence of the gene was determined. It has a G + C content of 71.5 % an d encodes a 27 amino acid signal sequence and the mature beta-lactamas e of 276 amino acids which has a mass of 29 146 Da. The enzyme appears to be unique to L. enzymogenes but its amino acid sequence shows a hi gh degree of homology with the amino acid sequences of the lactamase f rom Citrobacter diversus and other Class A beta-lactamases. The beta-l actamase gene of L. enzymogenes was expressed in Escherichia coli usin g pUC118 as the vector. The production of active beta-lactamase was hi ghest after the active growth phase of the expression host and reached levels which were about three times higher than those obtained with L . enzymogenes.