Protein structure. Engineering of a superhelicase through conformational control

Science. 2015 Apr 17;348(6232):344-7. doi: 10.1126/science.aaa0445.


Conformational control of biomolecular activities can reveal functional insights and enable the engineering of novel activities. Here we show that conformational control through intramolecular cross-linking of a helicase monomer with undetectable unwinding activity converts it into a superhelicase 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 the regulation of nucleic acid unwinding activity and introduces a monomeric superhelicase without nuclease activities, which may be useful for biotechnological applications.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / genetics
  • Cross-Linking Reagents / chemistry
  • Crystallography, X-Ray
  • DNA Helicases / chemistry*
  • DNA Helicases / genetics
  • DNA Replication*
  • DNA, Single-Stranded / chemistry*
  • Deoxyribonucleases / chemistry
  • Deoxyribonucleases / genetics
  • Enzyme Stability
  • Escherichia coli Proteins / chemistry*
  • Escherichia coli Proteins / genetics
  • Protein Conformation
  • Protein Engineering


  • Bacterial Proteins
  • Cross-Linking Reagents
  • DNA, Single-Stranded
  • Escherichia coli Proteins
  • pcrA protein, Bacteria
  • rep protein, E coli
  • Deoxyribonucleases
  • DNA Helicases