title: Toward single-enzyme molecule electrochemistry: [NiFe]-hydrogenase protein film voltammetry at nanoelectrodes.
abstract: We have scaled down electrochemical assays of redox-active enzymes enabling us to study small numbers of molecules. Our approach is based on lithographically fabricated Au nanoelectrodes with dimensions down to ca. 70 x 70 nm(2). We first present a detailed characterization of the electrodes using a combination of scanning electron microscopy, cyclic voltammetry, and finite-element modeling. We then demonstrate the viability of the approach by focusing on the highly active [NiFe]-hydrogenase from Allochromatium vinosum immobilized on polymyxin-pretreated Au. Using this system, we successfully demonstrate a distinct catalytic response from less than 50 enzyme molecules. These results strongly suggest the feasibility of using bioelectrochemistry as a new tool for studying redox enzymes at the single-molecule level.
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, Delft, The Netherlands.
authors.forename: Freek J M
authors.initials: FJ
authors.lastname: Hoeben
authors.forename: F Stefan
authors.initials: FS
authors.lastname: Meijer
authors.forename: Cees
authors.initials: C
authors.lastname: Dekker
authors.forename: Simon P J
authors.initials: SP
authors.lastname: Albracht
authors.forename: Hendrik A
authors.initials: HA
authors.lastname: Heering
authors.forename: Serge G
authors.initials: SG
authors.lastname: Lemay
mesh_terms: D002841:Chromatiaceae / Q000201:enzymology*; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry; D006864:Hydrogenase / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008958:Models, Molecular
chemical_list: D004800:Enzymes, Immobilized; C043296:nickel-iron hydrogenase; D006864:Hydrogenase