Cloning, sequencing, and site-directed mutagenesis of beta-lactamase gene from Streptomyces fradiae Y59.

The beta-lactamase gene from Streptomyces fradiae Y59 was cloned and sequenced. To determine which amino acid residues are critical in binding activity to blue dextran, chimera beta-lactamases were constructed and their binding abilities were determined. The results suggested that blue dextran binding may depend more on overall conformation of about two-thirds of the beta-lactamase molecule from the N terminus than on the primary structure.