MazE6-HIS antitoxin and MazF6-HSV toxin functionally and physically interact in vivo. A) Growth of E. coli BL21 (DE3) pLysE containing MazE6-HIS alone, B) MazF6-HSV alone, or C) MazE6-HIS co-produced with MazF6-HSV. Growth arrest due to MazF6-HSV production is recued by co-production of MazE6-HIS antitoxin. D) MazE6-HIS is present in the elution fraction, while MazF6-HSV is present in the unbound flow and wash fraction when each is produced alone. When co-produced, MazF6-HSV elutes primarily with MazE6-HIS, indicating that they physically interact. Data are representative of multiple independent experiments.