title: A virus-based single-enzyme nanoreactor.
abstract: Most enzyme studies are carried out in bulk aqueous solution, at the so-called ensemble level, but more recently studies have appeared in which enzyme activity is measured at the level of a single molecule, revealing previously unseen properties. To this end, enzymes have been chemically or physically anchored to a surface, which is often disadvantageous because it may lead to denaturation. In a natural environment, enzymes are present in a confined reaction space, which inspired us to develop a generic method to carry out single-enzyme experiments in the restricted spatial environment of a virus capsid. We report here the incorporation of individual horseradish peroxidase enzymes in the inner cavity of a virus, and describe single-molecule studies on their enzymatic behaviour. These show that the virus capsid is permeable for substrate and product and that this permeability can be altered by changing pH.
authors.affiliation: Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands.
authors.forename: Marta
authors.initials: M
authors.lastname: Comellas-Aragonès
authors.forename: Hans
authors.initials: H
authors.lastname: Engelkamp
authors.forename: Victor I
authors.initials: VI
authors.lastname: Claessen
authors.forename: Nico A J M
authors.initials: NA
authors.lastname: Sommerdijk
authors.forename: Alan E
authors.initials: AE
authors.lastname: Rowan
authors.forename: Peter C M
authors.initials: PC
authors.lastname: Christianen
authors.forename: Jan C
authors.initials: JC
authors.lastname: Maan
authors.forename: Benedictus J M
authors.initials: BJ
authors.lastname: Verduin
authors.forename: Jeroen J L M
authors.initials: JJ
authors.lastname: Cornelissen
authors.forename: Roeland J M
authors.initials: RJ
authors.lastname: Nolte
mesh_terms: D032701:Biomimetics / Q000379:methods*; D019149:Bioreactors; D002213:Capsid / Q000737:chemistry* / Q000648:ultrastructure; D004800:Enzymes, Immobilized / Q000737:chemistry*; D006735:Horseradish Peroxidase / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods*; D010539:Permeability
chemical_list: D004800:Enzymes, Immobilized; D006735:Horseradish Peroxidase