title: A Protein Rotaxane Controls the Translocation of Proteins Across a ClyA Nanopore.
abstract: Rotaxanes, pseudorotaxanes, and catenanes are supramolecular complexes with potential use in nanomachinery, molecular computing, and single-molecule studies. Here we constructed a protein rotaxane in which a polypeptide thread is encircled by a Cytolysin A (ClyA) nanopore and capped by two protein stoppers. The rotaxane could be switched between two states. At low negative applied potentials (<-50 mV) one of the protein stoppers resided inside the nanopore indefinitely. Under this configuration the rotaxane prevents the diffusion of protein molecules across the lipid bilayer and provides a useful platform for single-molecule analysis. High negative applied potentials (-100 mV) dismantled the interlocked rotaxane system by the forceful translocation of the protein stopper, allowing new proteins to be trapped inside or transported across the nanopore. The observed voltage threshold for the translocation of the protein stopper through the nanopore related well to the biphasic voltage dependence of the residence time measured for the freely diffusing protein stopper. We propose a model in which molecules translocate through a nanopore when the average dwell time decreases with the applied potential.
authors.affiliation: Department of Chemistry, University of Leuven, Leuven, 3001, Belgium.
authors.forename: Annemie
authors.initials: A
authors.lastname: Biesemans
authors.affiliation: Groningen Biomolecular Sciences & Biotechnology (GBB) Institute, University of Groningen, 9747 AG, Groningen, The Netherlands.
authors.forename: Misha
authors.initials: M
authors.lastname: Soskine
authors.affiliation: Groningen Biomolecular Sciences & Biotechnology (GBB) Institute, University of Groningen, 9747 AG, Groningen, The Netherlands.|Department of Chemistry, University of Leuven, Leuven, 3001, Belgium.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Maglia
mesh_terms: D004926:Escherichia coli / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism; D008958:Models, Molecular; D058608:Nanopores / Q000648:ultrastructure; D054353:Perforin / Q000737:chemistry / Q000378:metabolism*; D021381:Protein Transport; D043862:Rotaxanes / Q000737:chemistry / Q000378:metabolism*; D012485:Salmonella typhi / Q000737:chemistry / Q000378:metabolism*; D013762:Tetrahydrofolate Dehydrogenase / Q000737:chemistry / Q000378:metabolism*
chemical_list: D043862:Rotaxanes; D054353:Perforin; D013762:Tetrahydrofolate Dehydrogenase
keywords: ClyA nanopore; DHFR; protein translocation; rotaxane; voltage-dependent residence time