Engineering of a super-helicase through conformational control

Conformational control of biomolecular activities can reveal functional insights and enable the engineering of novel activities. Here, we show that conformational control through intramolecular crosslinking of a helicase monomer with undetectable unwinding activity converts it into a super-helicase that can unwind thousands of base pairs processively even against a large opposing force. A natural partner that enhances the helicase activity is shown to achieve its stimulating role also by selectively stabilizing the active conformation. Our work provides insight into how nature achieves the regulation of nucleic acid unwinding activity and introduces a monomeric super-helicase without nuclease activities which may be useful for biotechnological applications.