TY  - JOUR
AU  - Hrabakova, J.
AU  - Ataka, K.
AU  - Heberle, J.
AU  - Hildebrandt, P.
AU  - Murgida, D.
TI  - Long distance electron transfer in cytochrome c oxidase immobilised on electrodes. A surface enhanced resonance Raman spectroscopic study
JO  - Physical Chemistry Chemical Physics
VL  - 8
SN  - 1463-9076
CY  - Cambridge
PB  - RSC Publ.
M1  - PreJuSER-51336
SP  - 759 - 766
PY  - 2006
N1  - Record converted from VDB: 12.11.2012
AB  - Cytochrome c oxidase was tethered to a functionalised Ag electrode via a histidine-tag on the C-terminus of subunit I or II and embedded in a phospholipid bilayer. The uniformly oriented membrane-bound proteins were studied by surface enhanced resonance Raman spectroscopy (SERRS) that reveals preservation of the native structures of the heme a and heme a(3) sites. On the basis of time-dependent SERRS measurements, the rate constant for the heterogeneous electron transfer to heme a was determined to be 0.002 s(-1) independent of the enzyme orientation and the overpotential. Taking into account that the electrode-to-heme a distance is larger than 50 A, these findings suggest an electron hopping mechanism in which the Cu(A) center is not involved. Electrochemical reduction is restricted to heme a whereas electron transfer from heme a to heme a(3), which in solution occurs on the nanosecond time scale, is drastically slowed down. It may be that the network of cooperativities that links intramolecular electron transfer and proton translocation is perturbed in the immobilised enzyme, possibly due to the effect of the interfacial electric field.
KW  - Chemistry, Physical
KW  - Electrodes
KW  - Electron Transport Complex IV: chemistry
KW  - Enzymes, Immobilized: chemistry
KW  - Models, Chemical
KW  - Oxidation-Reduction
KW  - Physicochemical Phenomena
KW  - Silver: chemistry
KW  - Spectrum Analysis, Raman: methods
KW  - Surface Properties
KW  - Time Factors
KW  - Enzymes, Immobilized (NLM Chemicals)
KW  - Silver (NLM Chemicals)
KW  - Electron Transport Complex IV (NLM Chemicals)
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
C6  - pmid:16482317
UR  - <Go to ISI:>//WOS:000235608500011
DO  - DOI:10.1039/b513379n
UR  - https://juser.fz-juelich.de/record/51336
ER  -