TY  - JOUR
A1  - Peng, Lei
A1  - Utesch, Tillmann
A1  - Yarman, Aysu
A1  - Jeoung, Jae-Hun
A1  - Steinborn, Silke
A1  - Dobbek, Holger
A1  - Mroginski, Maria Andrea
A1  - Tanne, Johannes
A1  - Wollenberger, Ursula
A1  - Scheller, Frieder W.
T1  - Surface-Tuned Electron Transfer and Electrocatalysis of Hexameric Tyrosine-Coordinated Heme Protein
JF  - Chemistry - a European journal
N2  - 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.
KW  - electrochemistry
KW  - electron transfer
KW  - heme proteins
KW  - molecular modeling
KW  - monolayers
Y1  - 2015
U6  - https://doi.org/10.1002/chem.201405932
SN  - 0947-6539
SN  - 1521-3765
VL  - 21
IS  - 20
SP  - 7596
EP  - 7602
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Tanne, Johannes
A1  - Jeoung, Jae-Hun
A1  - Peng, Lei
A1  - Yarman, Aysu
A1  - Dietzel, Birgit
A1  - Schulz, Burkhard
A1  - Schad, Daniel
A1  - Dobbek, Holger
A1  - Wollenberger, Ursula
A1  - Bier, Frank Fabian
A1  - Scheller, Frieder W.
T1  - Direct Electron Transfer and Bioelectrocatalysis by a Hexameric, Heme Protein at Nanostructured Electrodes
JF  - Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis
N2  - 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.
KW  - HTHP
KW  - Nanohybrid
KW  - Poylaniline
KW  - Multiwalled carbon nanotube
Y1  - 2015
U6  - https://doi.org/10.1002/elan.201500231
SN  - 1040-0397
SN  - 1521-4109
VL  - 27
IS  - 10
SP  - 2262
EP  - 2267
PB  - Wiley-VCH
CY  - Weinheim
ER  -