RecGwed : A probable novel regulator in the resolution of branched DNA structures in mycobacteria.

Structure-specific helicases, such as RecG, play an important role in the resolution of recombination intermediates. A bioinformatic analysis of mycobacterial genomes led to the identification of a protein (RecGwed ) with a C-terminal "edge" domain, similar to the wedge domain of RecG. RecGwed is predominately found in the phylum Actinobacteria and in few human pathogens. Mycobacterium smegmatis RecGwed was able to bind branched DNA structures in vitro but failed to interact with single- or double-stranded DNA. The expression of recGwed in M. smegmatis cells was up-regulated during stationary phase/UV damage and down-regulated during MMS/H2 O2 treatment. These observations indicate the possible involvement of RecGwed in transactions during recombination events, that proceed though branched DNA intermediates.