ACTA BIOLOGICA CRACOVIENSIA

PHOTOSYNTHESIS, PHOTOCHEMISTRY, AND PHOTOPROTECTION BY CAROTENOIDS
2.19.
Comparison of the de-epoxidation of
violaxanthin associated with the
light-harvesting complexes of spinach and the
algae Mantoniella squamata (Prasinophyceae)
Susann Schaller1 , Małgorzata Jemioła-Rzemińska2 ,
Dariusz Latowski2 , Christian Wilhelm1 , Kazimierz Strzałka2 ,
Reimund Goss1 1Institute of Biology I, Plant Physiology, University of Leipzig,
Johannisallee 21-23, 04103 Leipzig, Germany,
schall@rz.uni-leipzig.de, rgoss@rz.uni-leipzig.de,
cwilhelm@rz.uni-leipzig.de
2Faculty of Biochemistry, Biophysics and Biotechnology,
Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland,
mjr@mol.uj.edu.pl, latowski@interia.pl, strzalka@mol.uj.edu.pl
In plants and algae the xanthophyll cycle (XC) plays an important
role for the adaptation to different light conditions. Under low light
conditions the major part of the light-harvesting pigment violaxanthin
(Vx) is associated with the proteins of the antenna system.
Under saturating light conditions Vx is released from its binding
site into the surrounding lipid phase, where it is converted to the
energy-dissipating pigment zeaxanthin (Zx) via the intermediate
antheraxanthin (Ax). This reaction is catalyzed by the enzyme Vx
de-epoxidase (VDE). In contrast to higher plants where the main
de-epoxidation product is Zx, the prasinophyceaen alga
Mantoniella squamata shows in vivo an incomplete XC, leading to
a strong accumulation of Ax. Another exceptional feature of M.
squamata is the presence of a unique type of light-harvesting complex
(LHCp) which shows a different structure and a more complex
pigment composition in comparison to other antenna proteins,
including the main PSII light-harvesting complex (LHCII) of higher
plants. In the present study we investigated the de-epoxidation of
Vx which was still associated with the light-harvesting complexes
(LHC) of spinach or M. squamata. The LHC were isolated with different
concentrations of natively bound lipids and Vx by sucrose
gradient centrifugation or successive cation precipitation. In both
LHC types the decrease of the concentration of LHC-associated Vx
was accompanied by a diminished content of the main thylakoid
lipid monogalactosyldiacylglycerol (MGDG), with the difference that
the LHCp contained much lower Vx concentrations than the LHCII.
Furthermore, the convertibility of LHC-associated Vx was studied
by addition of isolated VDE. The de-epoxidation of LHCII-associated
Vx depended on the Vx/MGDG ratio, i.e. a reduced Vx de-epoxidation
was observed below and above an optimal Vx/MGDG ratio
where nearly all Vx was efficiently converted. In contrast, the deepoxidation
of Vx associated with LHCp was more strongly influenced
by the Vx concentration or the MGDG content than the
Vx/MGDG ratio.
Vol. 53, suppl. 1, 2011
17–22 July 2011, Krakow, Poland
2.20.
Intramolecular charge-transfer state of
carbonyl carotenoids in LH1-RC complexes of
purple bacteria
Václav Šlouf1 , John D. Olsen2 , C. Neil Hunter2 ,
Tomáš Polívka1,3 1Institute of Physical Biology (University of South Bohemia),
Zámek 136, 373 33 Nové Hrady, Czech Republic,
slouf@greentech.cz
2Department of Molecular Biology and Biotechnology, The
University of Sheffield, Sheffield S10 2TN, United Kingdom,
J.Olsen@sheffield.ac.uk, C.N.Hunter@sheffield.ac.uk
3Institute of Plant Molecular Biology (Biological Centre, Czech
Academy of Sciences), Branišovská 31/1160, 370 05 Èeské
Budìjovice, Czech Republic, polivka@ufb.jcu.cz
Intramolecular charge-transfer (ICT) state is an excited state specific
of carbonyl carotenoids. ICT state is strongly coupled to the
S 1 state, forming new electronic state usually denoted as S 1 /ICT.
It is identified by its characteristic ICT-like transition, which
becomes pronounced in polar environment and it is red-shifted
from the well-known S 1 -S n transition (Frank et al., 2000).
Using femtosecond time-resolved spectroscopy, we performed
experiments on LH1-RC complexes of 1) wild-type
Rhodobacter sphaeroides with carbonyl carotenoid spheroidenone
2) Rhodobacter sphaeroides G1C strain containing a noncarbonyl
carotenoid neurosporene.
While LH1-RC complexes with neurosporene exhibited typical
S 1 -S n transition observed in other LH complexes having non-carbonyl
carotenoids, transient absorption spectrum of LH1-RC
complex with spheroidenone is dominated by a new spectral
band centred at 750 nm that we identified as due to the ICT state
of spheroidenone. The S 1 /ICT lifetime of spheroidenone in LH1-
RC complex is significantly shorter than the S 1 lifetime of neurosporene
in LH1-RC, suggesting more efficient S 1 -mediated
energy transfer from spheroidenone. This could be caused by the
increased S 0 →S 1 /ICT transition dipole moment and more
favourable spectral overlap of S 1 /ICT and bacteriochlorophyll Q y
(Polívka and Frank, 2010).
REFERENCES
FRANK HA, BAUTISTA JA, JOSUE J, PENDON Z, HILLER RGG, SHARPLES FP,
GOSZTOLA D, WASIELEWSKI MR. 2000. Effect of the solvent environment
on the spectroscopic properties and dynamics of the lowest
excited states of carotenoids. J. Phys. Chem. B 104: 4569-4577.
POLÍVKA T and FRANK HA. 2010. Molecular factors controlling photosynthetic
light harvesting by carotenoids. Acc. Chem. Res. 43:
1125-1134.
2.21.
Interconversion of the xanthophyll pigments
under heat stress in etiolated and green
seedlings of triticale
L. Kabashnikova1 , G. Savchenko1 , L. Abramchik1 ,
K. Strzałka2 1Institute of Biophysics and Cellular Engineering at NAS of
Belarus, Academicheskaya str. 220072, Minsk, Belarus,
kabashnikova@mail.ru
2Faculty of Biochemistry, Biophysics and Biotechnology,
Jagiellonian University, Krakow, Poland,
kazimierzstrzalka@gmail.com
The effect of heat stress (HS, 42-44 °C) on carotenoid composition
was studied in the leaves of short- and long-stem triticale cul-
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