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Dr Angel Orte DEPARTMENT OF PHYSICAL
CHEMISTRY – UNIVERSITY OF GRANADA |
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Research Lines. For more information on me, my publications,
interests,… please click here. |
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DNA labeling fluorescent dyes. Xanthene succinimidyl ester
derivates have been synthesized as amine-reactive derivative able to yield
stable covalently labelled biopolymers. The
spectral changes associated with its neutral-anion
transition allows to be used as a nucleic acid probe in a homogeneous
assay. |
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Synthesis and photophysical
study of novel xanthene derivatives. We are
synthesizing novel fluorescein derivatives in which the carboxylic group, formerly
believed to be indispensable, is replaced by other chemical substituents. This modification reduces the number of
possible negative charges, as well as prevents lactonization
of the chromophore in solution. This kind of new fluoresceins retains both the high extinction coefficient
and fluorescence quantum yield of fluorescein in
alkaline media, while the fluorescence quantum yield is close to zero when
they are dissolved in acidic media. These features are highly suitable for pH
probes. |
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Save the date! III
Jornadas Ibéricas de Fotoquímica Granada, 4-7 September 2011 |
Excited-state proton transfer reactions.
Our research in the last few years
involved the kinetic characterization of excited-state proton transfer
reactions and their effect on fluorophores’
properties. We determined the relevant rate constants of the ESPT reaction
and the spectral parameters related to absorption and emission, kinetic
equations and expressions for the fluorescence decay surface. For this, we
made use a new global compartmental analysis
approach. |
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Probing amyloidogenic
protein-protein interactions using single molecule fluorescence spectroscopy.
The mechanism of the early stages
of formation of amyloid fibrils, proteinaceus fibrils related to neurodegenerative
diseases like Alzheimer's and Parkinson's, is not
well understood. We take advantage of state-of-the-art single molecule
fluorescence methodologies to probe direct interactions between single
proteins in the earlyformation of pre-fibrillar oligomers. This will
provide a better understanding of the mechanisms of amyloid
fibril formation. |
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Contact Information: Department of Physical
Chemistry Faculty of Pharmacy Campus Cartuja,
S/N 18071, Granada (Spain) Tel. +34 958 243825 |
Fluorescence resonance energy transfer (FRET) in
DNA. The next research line is based
in exploiting FRET as a versatile tool to study biological systems. We
are developing sensors for the detection of specific DNA sequences that may
be related to certain genes. Different approaches and strategies have been used
to study FRET between new and improved fluorescein
derivatives labelling DNA probes and DNA intercalators.
The combination of these approaches with FLIM (fluorescence lifetime
imaging microscopy) shows their applicability to biological systems in
vivo. |
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Photophysical study of
novel xanthene derivatives by single-molecule
fluorescence spectroscopy (FCS). We have shown how the presence of buffer-mediated
proton transfer reactions also affects the ground state protonation
state. This has important implications when these fluorophores
are employed in fluorescence correlation spectroscopy (FCS). Thus,
buffer-mediated proton transfer reactions make the fluorescence
autocorrelation function from the xanthene dyes highly sensitive to some buffers
concentration. The analysis of FCS curves provided the kinetic parameters of
buffer-mediated proton transfer reactions in the ground state
. These are the same than those for the reaction in excited
state, confirming the equal nature of the process either in the ground- or
excited-state. This implicates that the ESPT reaction is promoted when a
sufficiently high concentration of buffer makes the reaction fast enough to
compete with fluorescence emission. |
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