Bactericidal and virucidal activity of the alkalophilic P395D/L241V/T343A mutant of vanadium chloroperoxidase

Aims: Vanadium chloroperoxidase and its directed evolution mutant P395D/L241V/T343A were investigated for their antibacterial and antiviral potential at slightly alkaline pH and at a H2O2 concentration that is low compared to current nonenzymatic formulations. Methods and Results: Two bacteria (the Gram-negative Pseudomonas aeruginosa and the Gram-positive Staphylococcus aureus) and two viruses (the enveloped Herpes Simplex Virus and the nonenveloped Coxsackievirus B4) were incubated with the P395D/L241V/T343A mutant, 10 mmol l(-1) H2O2 and 100 mmol l(-1) Br- at pH 8. Strong microbial reduction was observed and bactericidal and virucidal activities of the mutant were three to six orders of magnitude higher than for the wild-type enzyme. Conclusions: The P395D/L241V/T343A mutant of vanadium chloroperoxidase has a broad antimicrobial activity at alkaline conditions. Significance and Impact of the Study: For many disinfection formulations, antimicrobial activity at slightly alkaline pH values is required. To date, only the wild-type vanadium chloroperoxidase has been studied for its antibacterial activity, and only at acidic to neutral pH values. Its antiviral activity (e.g. useful for the cleaning of medical equipment) was not studied before. The observed activity for the alkalophilic P395D/L241V/T343A mutant is an important step forward in the application of this robust enzyme as a component in disinfection formulations.