Characterization of a Deinococcus radiodurans MazF: A UACA‐specific RNA endoribonuclease

Microbes are known to withstand environmental stresses by using chromosomal toxin–antitoxin systems. MazEF is one of the most extensively studied toxin–antitoxin systems. In stressful environments, MazF toxins modulate translation by cleaving single‐stranded RNAs in a sequence‐specific fashion. Previously, a chromosomal gene located at DR0417 in Deinococcus radiodurans was predicted to code for a MazF endoribonuclease (MazF(DR) (0417)); however, its function remains unclear. In the present study, we characterized the molecular function of MazF(DR) (0417). Analysis of MazF(DR) (0417)‐cleaved RNA sites using modified massively parallel sequencing revealed a unique 4‐nt motif, UACA, as a potential cleavage pattern. The activity of MazF(DR) (0417) was also assessed in a real‐time fluorometric assay, which revealed that MazF(DR) (0417) strictly recognizes the unique tetrad UACA. This sequence specificity may allow D. radiodurans to alter its translation profile and survive under stressful conditions.