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@PHDTHESIS{Cukkemane:1301,
author = {Cukkemane, Abhishek},
title = {{S}tructural and functional studies of a prokaryotic cyclic
nucleotide-gated channel},
volume = {4270},
issn = {0944-2952},
school = {Univ. Köln},
type = {Dr. (Univ.)},
address = {Jülich},
publisher = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
reportid = {PreJuSER-1301, Juel-4270},
series = {Berichte des Forschungszentrums Jülich},
pages = {VIII, 114 p.},
year = {2008},
note = {Record converted from VDB: 12.11.2012; Köln, Univ., Diss.,
2007},
abstract = {Ion channels gated by cyclic nucleotides have crucial roles
in cardiac and neuronal excitability and in signal
transduction of sensory neurons. On binding cyclic
nucleotides these channels are activated, which results an
increase in membrane conductance. Although a lot of
information is available on the function of these channel
proteins, the molecular events that relay ligand binding to
channel activation is not well understood. Here, I studied
ligand binding of prokaryotic cyclic nucleotide-activated
K$^{+}$ channels. One of them, the mlCNG channel from the
nitrogen-fixing bacterium Mesorhizobium loti was suitable
for biophysical characterization. One of the key questions
that I worked on was how gating of the channel affects its
ligand binding properties? I performed ligand binding
studies on the tetrameric mlCNG protein and its isolated
cyclic nucleotide-binding domain (CNBD). Affinity of cyclic
nucleotides to the full-length mlCNG protein and to the CNBD
was determined using spectroscopic methods. Both, the mlCNG
channel and the CNBD bind cAMP in a non-cooperative manner
with similar binding affinity. These results indicate that
either no appreciable binding energy is required for
activation, or the conformational change in the CNBD is the
activation step itself. Crystallography experiments were
performed on the mlCNG channel. Two-dimensional crystals
were obtained in which the channel proteins were ordered in
a square lattice. The channel proteins were assembled as
tetramers and were arranged in a head-to tail fashion. The
crystal diffracts to 15 Å. This is an excellent starting
condition for future work to eventually obtain a structure
at atomic resolution.},
cin = {INB-1},
cid = {I:(DE-Juel1)VDB804},
pnm = {Grundlagen für zukünftige Informationstechnologien},
pid = {G:(DE-Juel1)FUEK412},
typ = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
url = {https://juser.fz-juelich.de/record/1301},
}