title: Spectroscopic Observation of Calcium-Induced Reorientation of Cellobiose Dehydrogenase Immobilized on Electrodes and its Effect on Electrocatalytic Activity.
abstract: Cellobiose dehydrogenase catalyzes the oxidation of various carbohydrates and is considered as a possible anode catalyst in biofuel cells. It has been shown that the catalytic performance of this enzyme immobilized on electrodes can be increased by presence of calcium ions. To get insight into the Ca(2+) -induced changes in the immobilized enzyme we employ surface-enhanced vibrational (SERR and SEIRA) spectroscopy together with electrochemistry. Upon addition of Ca(2+) ions electrochemical measurements show a shift of the catalytic turnover signal to more negative potentials while SERR measurements reveal an offset between the potential of heme reduction and catalytic current. Comparing SERR and SEIRA data we propose that binding of Ca(2+) to the heme induces protein reorientation in a way that the electron transfer pathway of the catalytic FAD center to the electrode can bypass the heme cofactor, resulting in catalytic activity at more negative potentials.
authors.affiliation: Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin (Germany).
authors.forename: Patrycja
authors.initials: P
authors.lastname: Kielb
authors.affiliation: Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin (Germany).
authors.forename: Murat
authors.initials: M
authors.lastname: Sezer
authors.affiliation: Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin (Germany).
authors.forename: Sagie
authors.initials: S
authors.lastname: Katz
authors.affiliation: Department of Biochemistry and Structural Biology, Lund University, PO Box 124, 221 00 Lund (Sweden).
authors.forename: Francesca
authors.initials: F
authors.lastname: Lopez
authors.affiliation: Department of Biochemistry and Structural Biology, Lund University, PO Box 124, 221 00 Lund (Sweden).
authors.forename: Christopher
authors.initials: C
authors.lastname: Schulz
authors.affiliation: Department of Biochemistry and Structural Biology, Lund University, PO Box 124, 221 00 Lund (Sweden).
authors.forename: Lo
authors.initials: L
authors.lastname: Gorton
authors.affiliation: Department of Food Science and Technology, BOKU - University of Natural Resources and Life Science, Muthgasse 18, 1190 Vienna (Austria).
authors.forename: Roland
authors.initials: R
authors.lastname: Ludwig
authors.affiliation: Institüt für Biochemie und Biologie, Universität Potsdam, Karl Liebknecht Strasse 24-25, 14476 Golm (Germany).
authors.forename: Ulla
authors.initials: U
authors.lastname: Wollenberger
authors.affiliation: Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin (Germany).
authors.forename: Ingo
authors.initials: I
authors.lastname: Zebger
authors.affiliation: Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin (Germany). inez.weidinger@tu-berlin.de.
authors.forename: Inez M
authors.initials: IM
authors.lastname: Weidinger
mesh_terms: D002118:Calcium / Q000737:chemistry* / Q000378:metabolism; D002237:Carbohydrate Dehydrogenases / Q000737:chemistry / Q000378:metabolism*; D055664:Electrochemical Techniques; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism*; D013057:Spectrum Analysis; D013499:Surface Properties
chemical_list: D004800:Enzymes, Immobilized; D002237:Carbohydrate Dehydrogenases; C019859:cellobiose-quinone oxidoreductase; D002118:Calcium
keywords: cellobiose dehydrogenase; electron transfer; enzyme catalysis; spectroelectrochemistry; surface-enhanced vibrational spectroscopy