Replicative helicases are essential for DNA replication in organisms across all domains of life. The steric exclusion model of unwinding, where one strand is encircled by the hexameric helicase and the other is excluded from the central channel during unwinding, is widely accepted. However, many details of the helicase loading and unwinding mechanisms remain unknown. The role of the excluded strand is increasingly being recognized as a significant factor in helicase unwinding mechanisms. Recently, our group showed that an interaction between the excluded strand and the outer surface of the 3’-5’ MCM helicase from Sulfolobus solfataricus (Sso) is critical for unwinding activity.Using single-molecule FRET, we now show that this interaction also exists for the hexameric E.coli DnaB (EcDnaB) helicase, which has an opposite 5’-3’ polarity, and that similar dynamics are exhibited by both helicases. However, this interaction does not stimulate unwinding in the case of EcDnaB, and mutational analysis shows that disrupting the wrapping interaction instead leads to enhanced unwinding. This suggests that the wrapping interaction can have different roles that depend on helicase polarity and replisome architecture. Two hyperactive EcDnaB mutants were identified and characterized during the mutational analysis. These novel mutants have ∼20-fold enhanced unwinding activity that is not dependent on enhanced ATPase rates or the wrapping interaction. We hypothesize that these mutants may provide insight into the structural changes required for DNA unwinding by EcDnaB. Details of DNA unwinding mechanisms are continually being revealed, and it is likely that many helicases utilize an excluded strand wrapping interaction. However, the excluded strand interaction could play varying roles during DNA replication initiation and elongation depending on the local replisome architecture.