Modified Listeria bacteriophage lysin genes (ply) allow efficient overexpression and one-step purification of biochemically active fusion proteins.

Listeria bacteriophage lytic enzymes are useful for in vitro applications such as rapid, gentle cell disruption, and they provide new approaches as selective antimicrobial agents for destruction of Listeria monocytogenes in contaminated foods. We describe here the amino-terminal modification of three cloned Listeria phage lysin genes (ply), resulting in fusion proteins with a 12-amino-acid leader containing six consecutive histidine residues. The recombinant enzymes retain their native specific activity and can be efficiently overproduced in Escherichia coli. By one-step metal chelate affinity chromatography, active lysins could be purified to more than 90% homogeneity.