Features of DNA Helicase Encoded by the uvrD Gene of Deinococcus radiodurans R1 in Escherichia coli K-12 Cells

Abstract

Reparative helicase II of Deinococcus radiodurans performs an unexpected critical function in repair of double-strand DNA breaks through the mechanism of extended synthesis-dependent strand annealing (ESDSA), while it is considered as an optional participant in the RecF pathway of recombinational repair in Escherichia coli. A fragment of genomic DNA of the radioresistant bacterium Deinococcus radiodurans with the uvrD gene encoding DNA helicase II, which is involved in excision repair of nucleotides, mismatch repair, and recombinational repair and replication, was cloned in the cells of the model object, Escherichia coli K-12. The pCR 2.1-uvrD+ plasmid restores resistance to ultraviolet light of mutant cells of Escherichia coliuvrD–, helD–, and rep– defective in reparative helicase II, helicase IV, and replicative helicase Rep, respectively, almost to the level of wild-type AB1157 and uvrD+, and, to a lesser extent, the strain with a mutation in the recQ gene encoding the key helicase of recombinational repair RecQ. The protective effect is also noticeable when strains with the plasmid are irradiated with γ-rays. It is established that Deinococcus radiodurans UvrD helicase possesses broad possibilities.