Because phage enzymes are so efficient in killing pathogenic bacteria, they may be valuable tools in controlling biowarfare bacteria. To determine the feasibility of the approach, we identified a lytic enzyme from the gamma phage that is specific for
Bacillus anthracis [
15]. In cloning experiments using the gamma-phage DNA, we identified a ~700 bp ORF in the phage genome encoding a 26 kDa product very similar in size and features to a variety of
Bacillus and
Listeria, phage lysins. The gamma lysin, referred to as PlyG, was then purified to homogeneity by a two-step ion exchange chromatography procedure and tested for its lethal action on gamma phage sensitive
bacilli. Three seconds after contact, as little as 10 ug of PlyG mediated a 5,000-fold decrease in viable counts of a ~10
7 bacillus culture [
8]. This lethal activity was observed in growth media, phosphate buffer, and even human blood. When the enzyme was then tested against five mutant
B. anthracis strains and ten different virulent
B. anthracis strains isolated worldwide, it was found to be lethal for them all. Although PlyG has no effect on
B. anthracis spores, we discovered that the addition of the germinant L-alanine after a short heat shock of 60C resulted in the rapid germination of the spore, at which time the enzyme was rapidly lethal.