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@PHDTHESIS{Heitbrink:44314,
author = {Heitbrink, Dirk},
title = {{I}nfrarotspektroskopische {U}ntersuchungen zum
{M}echanismus der {C}ytochrom-c-{O}xidase},
volume = {3969},
issn = {0944-2952},
school = {Univ. Düsseldorf},
type = {Dr. (Univ.)},
address = {Jülich},
publisher = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
reportid = {PreJuSER-44314, Juel-3969},
series = {Berichte des Forschungszentrums Jülich},
pages = {II, 114 p.},
year = {2002},
note = {Record converted from VDB: 12.11.2012; Düsseldorf, Univ.,
Diss., 2002},
abstract = {Cytochrome c oxidase is a complex biological machinery,
which couples the reduction of oxygen to a vectorial
transport of protons across the membrane. To achieve this,
the protein takes up eight protons, four electrons, and an
oxygen molecule. The electrons and four of the eight protons
are used for the reduction of oxygen to produce water. The
remaining four protons are pumped across the membrane. In
this work, Fourier-transorm infrared spectroscopy was
applied to provide insight into the structural and
functional relationships of the complex catalytic cycle. To
accomplish this, different strategies were applied: The
results obtained with the $\textit{fully reduced}$, CO-bound
cytochrome c oxidase from bovine heart showed for the first
time the possibility of performing difference spectroscopy
on this enzyme with a time-resolution of 5 $\mu$s in the
range of 2200 to 950 cm$^{-1}$. The evaluation of the data
revealed a dynamic link between the transient binding of CO
to Cu$_{B}$ and the movement of an amino acid side chain
(E286) approximately 12 $\mathring{A}$ away. This amino acid
is part of the D-channel and thought to play an important
role in guiding the protons either into the binuclear center
or through the membrane. The results presented in this work
suggest a mechanism in which oxygen binding is controlled
via E286. The outcome of the measurements with the
$\textit{two electron-reduced}$, CO-bound cytochrome c
oxidase from $\textit{Rhodobacter sphaeroides}$ indicate the
deprotonation of E286 during electron transfer from heme
a$_{3}$ to heme a. This result contradicts the current model
of the catalytic-cycle because this deprotonation suggests
an uptake of just one proton rather than two through the
K-channel. Redox difference spectra of wild type and mutant
cytochrome c oxidase obtained with the attenuated total
reflection technique pointed out the precise assignment of a
band feature. This signal was clearly attributed to a
conformational change of the side chain of amino acid E286.
For the first time it was possible to record a difference
spectrum in the IR of the oxidative part of the catalytic
cycle. The F $\textit{minus}$ O spectrum showed an
involvement of a tyrosine which undergoes deprotonation.},
cin = {IBI-2},
cid = {I:(DE-Juel1)VDB58},
pnm = {Biologische Strukturforschung},
pid = {G:(DE-Juel1)FUEK96},
typ = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
url = {https://juser.fz-juelich.de/record/44314},
}