title: Protein structure. Engineering of a superhelicase through conformational control.
abstract: 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.
authors.affiliation: Physics Department and Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
authors.forename: Sinan
authors.initials: S
authors.lastname: Arslan
authors.affiliation: Physics Department and Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
authors.forename: Rustem
authors.initials: R
authors.lastname: Khafizov
authors.affiliation: Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Thomas
authors.affiliation: Physics Department and Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
authors.forename: Yann R
authors.initials: YR
authors.lastname: Chemla
authors.affiliation: Physics Department and Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Howard Hughes Medical Institute, University of Illinois, Urbana, IL 61801, USA. tjha@illinois.edu.
authors.forename: Taekjip
authors.initials: T
authors.lastname: Ha
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D003432:Cross-Linking Reagents / Q000737:chemistry; D018360:Crystallography, X-Ray; D004265:DNA Helicases / Q000737:chemistry* / Q000235:genetics; D004261:DNA Replication; D004277:DNA, Single-Stranded / Q000737:chemistry*; D003851:Deoxyribonucleases / Q000737:chemistry / Q000235:genetics; D004795:Enzyme Stability; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics; D011487:Protein Conformation; D015202:Protein Engineering
chemical_list: D001426:Bacterial Proteins; D003432:Cross-Linking Reagents; D004277:DNA, Single-Stranded; D029968:Escherichia coli Proteins; C084217:pcrA protein, Bacteria; C506744:rep protein, E coli; D003851:Deoxyribonucleases; D004265:DNA Helicases