Crystal Structures of Complexes of PcrA DNA Helicase with a DNA Substrate Indicate

between domains 1A and 2A that is lined with a number of conserved sequence motifs that are characteristic of helicases (Gorbalenya and Koonin, 1993). PcrA is a member of a large family of helicases that have a 39±59 directionality (Bird et al., 1998a) and share a number o