PprA: A novel protein from Deinococcus radiodurans that stimulates DNA ligation

Abstract

The extraordinary radiation resistance of Deinococcus radiodurans results from the efficient capacity of the bacterium to repair DMA double-strand breaks. By analysing the DNA damage repair-deficient mutant, KH311, a unique radiation-inducibie gene (designated pprA) responsible for loss of radiation resistance was identified. Investigations in vitro showed that the gene product of pprA (ParA) preferentially bound to double-stranded DNA carrying strand breaks, inhibited Escherichia coli exonuclease III activity, and stimulated the DHA end-joining reaction catalysed by ATP-dependent and NAD-dependent DNA ligases. These results suggest that D. radiodurans has a radiation-induced non-homologous end-joining repair mechanism in which PprA plays a critical role.