Biochemical and Functional Characterization of the NurA-HerA Complex from Deinococcus radiodurans

Abstract

Deinococcus radiodurans NurA (DrNurA) was identified as a manganese-dependent 5'-to-3' ssDNA/dsDNA exonuclease/endonuclease, and Deinococcus radiodurans HerA (DrHerA) was identified as an ATPase. Physical interactions between DrNurA and DrHerA explained mutual stimulation of their activities. The N-terminal HAS domain on DrHerA was identified as the interaction domain. Several essential functional sites on DrNurA and DrHerA were characterized. Both DrHerA and DrNurA showed mesophilic biochemical features, with their optimum activity temperatures 10 °C to 15 °C higher than their optimum growth temperatures in vitro. Knockout of nurA or herA led to abnormal cell proliferation and reduced intermolecular recombination efficiency but no obvious effect on radioresistence.