Plays a role in the inhibition of the host toxin-antitoxin (TA) system. These modules made by the host and composed of a toxic gene and a neutralizing gene play role in stress response and programmed cell death. Gp4.5 interacts with the host protease lon to neutralize the degradation of the antitoxin that would result in the activation of the toxin and the destruction of the bacteria. Interacts with host lon protease; this interaction prevents the degradation of antitoxin by lon and thus the toxin activation.