Two heads are better than one: Single stranded DNA translocation of UvrD-family dimers vs. monomers

UvrD-family Superfamily 1A helicases are ATP-dependent motor proteins involved in DNA replication, recombination, repair, and transcription. While UvrD-family monomers can translocate along single-stranded (ss) DNA with 3'-to-5' directionality, they must be activated by dimerization to become helicases in the absence of force or accessory factors. Mycobacterium tuberculosis UvrD1 forms dimers via a disulfide bond between native cysteines in the 2B sub-domains, and E. coli UvrD uses the same 2B domain interface to form non-covalent dimers.