T4 DNA helicase (gp41) is a hexameric, DnaB-like helicase that unwinds DNA with 5′ to 3′ polarity (1-3). Helicase activity has been shown to be stimulated upon association with gp61 or in coupled assays with the T4 DNA polymerase gp43 (4, 5). T4 replication helicase (gp41) and polymerase (gp43) can carry out ATP-dependent strand displacement DNA synthesis at physiological rates with high processivity in the absence of other T4 DNA replication proteins.
The physical purity of this enzyme is ≥98% as assessed by SDS-PAGE with Coomassie® blue staining (Fig. 1).