A RelE/ParE superfamily toxin in Vibrio parahaemolyticus has DNA nicking endonuclease activity

RelE and ParE family toxins belong to the RelE/ParE superfamily, despite distinct biological activities; RelE toxins are a protein synthesis inhibitor by cleaving mRNA, while ParE toxins have inhibitory activity toward Gyr. We found that the Vibrio parahaemolyticus toxin, Vp1843, unlike RelE and ParE toxins, exhibited a DNA nicking endonuclease activity. The present result may assign DNA nicking endonuclease activity of Vp1843 as a third biological activity in the RelE/ParE superfamily toxins.170