To ensure efficient duplex unwinding, eIF4B and eIF4G cooperatively activate the duplex unwinding activity of eIF4A.
The activated helicase CMG exerts unwinding activity in the 3′ 5′ direction.
OsSUV3 can use mainly ATP or dATP as energy source for the unwinding activity and it cannot unwind the blunt-end duplex DNA substrate.
OsSUV3 exhibits bidirectional DNA unwinding activity and is unable to unwind the blunt-end DNA duplex substrate.
Moreover, association of Top3α and BLAP75 with BLM stimulates its HJ unwinding activity; however, neither WRN nor E. coli RecQ HJ unwinding was stimulated by Top3α BLAP75 [ 20].
(B) Measurement of dsRNA unwinding activity of ZIKV helicase.
RNA unwinding activity of ZIKV helicase was assayed using a radiolabeled dsRNA substrate.
Both complexes inhibited the unwinding activity of Hjm and the ligation activity of DNA Ligase I.
The RNA unwinding activity was assayed using radiolabeled double-stranded (ds) RNA, in the presence of Mg2+, ATP, and various concentrations of enzyme (Fig. 1B).
The accessory proteins eIF4G, eIF4B, and eIF4H enhance the duplex unwinding activity of eIF4A, but the extent to which they modulate eIF4A activity is poorly understood.
Most of these proteins also exhibit the nucleic acid unwinding activity [32], [33], [34], [35], [36].
