@article{PengUteschYarmanetal.2015, author = {Peng, Lei and Utesch, Tillmann and Yarman, Aysu and Jeoung, Jae-Hun and Steinborn, Silke and Dobbek, Holger and Mroginski, Maria Andrea and Tanne, Johannes and Wollenberger, Ursula and Scheller, Frieder W.}, title = {Surface-Tuned Electron Transfer and Electrocatalysis of Hexameric Tyrosine-Coordinated Heme Protein}, series = {Chemistry - a European journal}, volume = {21}, journal = {Chemistry - a European journal}, number = {20}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0947-6539}, doi = {10.1002/chem.201405932}, pages = {7596 -- 7602}, year = {2015}, abstract = {Molecular modeling, electrochemical methods, and quartz crystal microbalance were used to characterize immobilized hexameric tyrosine-coordinated heme protein (HTHP) on bare carbon or on gold electrodes modified with positively and negatively charged self-assembled monolayers (SAMs), respectively. HTHP binds to the positively charged surface but no direct electron transfer (DET) is found due to the long distance of the active sites from the electrode surfaces. At carboxyl-terminated surfaces, the neutrally charged bottom of HTHP can bind to the SAM. For this "disc" orientation all six hemes are close to the electrode and their direct electron transfer should be efficient. HTHP on all negatively charged SAMs showed a quasi-reversible redox behavior with rate constant k(s) values between 0.93 and 2.86 s(-1) and apparent formal potentials E-app(0)' between -131.1 and -249.1 mV. On the MUA/MU-modified electrode, the maximum surface concentration corresponds to a complete monolayer of the hexameric HTHP in the disc orientation. HTHP electrostatically immobilized on negatively charged SAMs shows electrocatalysis of peroxide reduction and enzymatic oxidation of NADH.}, language = {en} } @article{TanneJeoungPengetal.2015, author = {Tanne, Johannes and Jeoung, Jae-Hun and Peng, Lei and Yarman, Aysu and Dietzel, Birgit and Schulz, Burkhard and Schad, Daniel and Dobbek, Holger and Wollenberger, Ursula and Bier, Frank Fabian and Scheller, Frieder W.}, title = {Direct Electron Transfer and Bioelectrocatalysis by a Hexameric, Heme Protein at Nanostructured Electrodes}, series = {Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis}, volume = {27}, journal = {Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis}, number = {10}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1040-0397}, doi = {10.1002/elan.201500231}, pages = {2262 -- 2267}, year = {2015}, abstract = {A nanohybrid consisting of poly(3-aminobenzenesulfonic acid-co-aniline) and multiwalled carbon nanotubes [MWCNT-P(ABS-A)]) on a gold electrode was used to immobilize the hexameric tyrosine-coordinated heme protein (HTHP). The enzyme showed direct electron transfer between the heme group of the protein and the nanostructured surface. Desorption of the noncovalently bound heme from the protein could be excluded by control measurements with adsorbed hemin on aminohexanthiol-modified electrodes. The nanostructuring and the optimised charge characteristics resulted in a higher protein coverage as compared with MUA/MU modified electrodes. The adsorbed enzyme shows catalytic activity for the cathodic H2O2 reduction and oxidation of NADH.}, language = {en} } @article{PengYarmanJetzschmannetal.2016, author = {Peng, Lei and Yarman, Aysu and Jetzschmann, Katharina J. and Jeoung, Jae-Hun and Schad, Daniel and Dobbek, Holger and Wollenberger, Ursula and Scheller, Frieder W.}, title = {Molecularly Imprinted Electropolymer for a Hexameric Heme Protein with Direct Electron Transfer and Peroxide Electrocatalysis}, series = {SENSORS}, volume = {16}, journal = {SENSORS}, publisher = {MDPI}, address = {Basel}, issn = {1424-8220}, doi = {10.3390/s16030272}, pages = {1343 -- 1364}, year = {2016}, abstract = {For the first time a molecularly imprinted polymer (MIP) with direct electron transfer (DET) and bioelectrocatalytic activity of the target protein is presented. Thin films of MIPs for the recognition of a hexameric tyrosine-coordinated heme protein (HTHP) have been prepared by electropolymerization of scopoletin after oriented assembly of HTHP on a self-assembled monolayer (SAM) of mercaptoundecanoic acid (MUA) on gold electrodes. Cavities which should resemble the shape and size of HTHP were formed by template removal. Rebinding of the target protein sums up the recognition by non-covalent interactions between the protein and the MIP with the electrostatic attraction of the protein by the SAM. HTHP bound to the MIP exhibits quasi-reversible DET which is reflected by a pair of well pronounced redox peaks in the cyclic voltammograms (CVs) with a formal potential of -184.4 +/- 13.7 mV vs. Ag/AgCl (1 M KCl) at pH 8.0 and it was able to catalyze the cathodic reduction of peroxide. At saturation the MIP films show a 12-fold higher electroactive surface concentration of HTHP than the non-imprinted polymer (NIP).}, language = {en} } @misc{PengYarmanJetzschmannetal.2017, author = {Peng, Lei and Yarman, Aysu and Jetzschmann, Katharina J. and Jeoung, Jae-Hun and Schad, Daniel and Dobbek, Holger and Wollenberger, Ursula and Scheller, Frieder W.}, title = {Molecularly imprinted electropolymer for a hexameric heme protein with direct electron transfer and peroxide electrocatalysis}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-400627}, pages = {11}, year = {2017}, abstract = {For the first time a molecularly imprinted polymer (MIP) with direct electron transfer (DET) and bioelectrocatalytic activity of the target protein is presented. Thin films of MIPs for the recognition of a hexameric tyrosine-coordinated heme protein (HTHP) have been prepared by electropolymerization of scopoletin after oriented assembly of HTHP on a self-assembled monolayer (SAM) of mercaptoundecanoic acid (MUA) on gold electrodes. Cavities which should resemble the shape and size of HTHP were formed by template removal. Rebinding of the target protein sums up the recognition by non-covalent interactions between the protein and the MIP with the electrostatic attraction of the protein by the SAM. HTHP bound to the MIP exhibits quasi-reversible DET which is reflected by a pair of well pronounced redox peaks in the cyclic voltammograms (CVs) with a formal potential of -184.4 ± 13.7 mV vs. Ag/AgCl (1 M KCl) at pH 8.0 and it was able to catalyze the cathodic reduction of peroxide. At saturation the MIP films show a 12-fold higher electroactive surface concentration of HTHP than the non-imprinted polymer (NIP).}, language = {en} }