title: Direct electrochemical interaction between a modified gold electrode and a bacterial membrane extract.
abstract: A novel electrochemical approach is described for redox-active membrane proteins. A total membrane extract (in the form of vesicles) of Bacillus subtilis is tethered onto gold surfaces modified with cholesterol based thiols. The membrane vesicles remain intact on the surface and do not rupture or fuse to form a planar bilayer. Oxidation/reduction signals are obtained of the natural co-enzyme, menaquinone-7, located in the membrane. The membrane protein, succinate menaquinone oxidoreductase (SQR), remains in the vesicles and is able to reduce fumarate using menaquinone as mediator. The catalysis of the reverse reaction (oxidation of succinate), which is the natural catalytic function of SQR, is almost absent with menaquinone. However, adding the co-enzyme ubiquinone, which has a reduction potential that is about 0.2 V higher, restores the succinate oxidation activity.
authors.affiliation: Institute of Molecular Biophysics, University of Leeds, Leeds LS2 9JT, UK. Jeuken@leeds.ac.uk
authors.forename: Lars J C
authors.initials: LJ
authors.lastname: Jeuken
authors.forename: Simon D
authors.initials: SD
authors.lastname: Connell
authors.forename: Mohammed
authors.initials: M
authors.lastname: Nurnabi
authors.forename: John
authors.initials: J
authors.lastname: O'Reilly
authors.forename: Peter J F
authors.initials: PJ
authors.lastname: Henderson
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Evans
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Bushby
mesh_terms: D001412:Bacillus subtilis / Q000737:chemistry*; D002457:Cell Extracts / Q000737:chemistry*; D002462:Cell Membrane / Q000737:chemistry*; D004563:Electrochemistry; D004566:Electrodes; D004926:Escherichia coli / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry; D018625:Microscopy, Atomic Force; D015394:Molecular Structure
chemical_list: D002457:Cell Extracts; D008055:Lipids; D006046:Gold