RT Journal Article SR Electronic(1) A1 Zegeye, Ephrem Debebe A1 Balasingham, Seetha V. A1 Laerdahl, Jon K. A1 Homberset, Håvard A1 Tønjum, ToneYR 2012 T1 Mycobacterium tuberculosis RecG binds and unwinds model DNA substrates with a preference for Holliday junctions JF Microbiology, VO 158 IS 8 SP 1982 OP 1993 DO https://doi.org/10.1099/mic.0.058693-0 PB Microbiology Society, SN 1465-2080, AB The RecG enzyme, a superfamily 2 helicase, is present in nearly all bacteria. Here we report for the first time that the recG gene is also present in the genomes of most vascular plants as well as in green algae, but is not found in other eukaryotes or archaea. The precise function of RecG is poorly understood, although ample evidence shows that it plays critical roles in DNA repair, recombination and replication. We further demonstrate that Mycobacterium tuberculosis RecG (RecGMtb) DNA binding activity had a broad substrate specificity, whereas it only unwound branched-DNA substrates such as Holliday junctions (HJs), replication forks, D-loops and R-loops, with a strong preference for the HJ as a helicase substrate. In addition, RecGMtb preferentially bound relatively long (≥40 nt) ssDNA, exhibiting a higher affinity for the homopolymeric nucleotides poly(dT), poly(dG) and poly(dC) than for poly(dA). RecGMtb helicase activity was supported by hydrolysis of ATP or dATP in the presence of Mg2+, Mn2+, Cu2+ or Fe2+. Like its Escherichia coli orthologue, RecGMtb is also a strictly DNA-dependent ATPase., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.058693-0