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Introduction
Publications
Publications (19)
The majority of life on Earth depends directly or indirectly on the sun as a source of energy. The initial step of photosynthesis is facilitated by light-harvesting complexes, which capture and transfer light energy into the reaction centers (RCs). Here, we analyzed the organization of photosynthetic (PS) complexes in the bacterium G. phototrophica...
Detailed discussion of the BChl a stoichiometry in PS complex.
BChl, bacteriochlorophyll; PS, photosynthetic.
(DOC)
Flash-induced absorbance spectra of purified photosynthetic complexes of G. phototrophica.
As expected for the type 2 RC, the signal is dominated by signatures of the oxidized primary donor (P870+): bleaching around 865 nm, electrochomic shift of the accessory BChl a around 800 nm and bleaching of the Qx band of the primary donor at 600 nm. BChl, b...
Parameters used for computation of the steady-state optical spectra of G. phototrophica PS complex.
PS, photosynthetic.
(PDF)
Absorption spectra of PS membranes from G. phototrophica (red) and R. rubrum (grey).
PS, photosynthetic.
(TIF)
Upper panel: size exclusion chromatography of the partially purified PS complexes from G. phototrophica. The blue line recorded at 820 nm shows the fraction with the purified complex, and the red trace at 490 nm represent the carotenoids. Lower panel: the absorption spectrum of the obtained complex (blue) and the spectrum of the “free” carotenoids...
Example of a raw TEM image of G. phototrophica complexes.
TEM, transmission electron microscopy.
(TIF)
PS complex of G. phototrophica analyzed by native and SDS polyacrylamide gel electrophoresis.
(A) Clear-native gel electrophoresis of G. phototrophica membrane complexes in comparison with membrane complexes of R. rubrum and Synechocystis sp. PCC 6803; the membranes were solubilized using 2% dodecyl-β-maltoside and loaded on 4%–14% clear-native gel...
BChl a fluorescence induction and relaxation recorded using the kinetic fluorometer FL-3000 (Photon Systems Instruments Ltd., Brno, Czech Republic).
The BChl fluorescence induction transient was elicited by a 140 μs-long square-wave pulse of light with an intensity of approximately 0.1 mol photon m−2s−1 provided by an array of blue-green 505 nm Lux...
Estimated angular distance between neighboring subunits of the PS complex.
The angle was measured as shown in the insert. The data were derived from 23 measurements from 4 individual complex images. PS, photosynthetic.
(TIF)
The spectro-temporal datasets obtained from the measurements were analyzed globally by fitting package DAFit (Pascher Instruments).
To visualize the excited state dynamics, we assumed that the excited states evolved according to a sequential, irreversible scheme A → B, B → C, C → D. The arrows represent increasingly slower processes and the time co...
Comparison of B816 and B868 absorption bands.
Red line: absorption spectrum of G. phototrophica PS complex. Grey area: absorption spectrum of R. rubrum complex scaled and blue-shifted to match the B868 band. Blue area: the difference between the red and grey spectra, corresponds to the pure spectrum of the B816 absorption band. The ratio of B816 an...
RC-LH1-PufX complexes from a genetically modified strain of Rhodobacter sphaeroides that accumulates carotenoids with very long conjugation were studied by ultrafast transient absorption spectroscopy. The complexes predominantly bind the carotenoid diketospirilloxanthin, constituting about 75% of the total carotenoids, which has 13 conjugated C=C b...
A quenching mechanism mediated by the orange carotenoid protein (OCP) is one of the ways cyanobacteria protect themselves against photooxidative stress. Here, we present a femtosecond spectroscopic study comparing OCP and RCP (red carotenoid protein) samples binding different carotenoids. We confirmed significant changes in carotenoid configuration...
In order to estimate the possible structure of the unknown carbonyl carotenoid related to isofucoxanthin from Chromera velia denoted as isofucoxanthin-like carotenoid (Ifx-l), we employed steady-state and ultrafast time-resolved spectroscopic techniques to investigate spectroscopic properties of Ifx-l in various solvents. The results were compared...
The major light-harvesting complex of Amphidinium (A.) carterae, chlorophyll-a–chlorophyll-c
2–peridinin–protein complex (acpPC), was studied using ultrafast pump-probe spectroscopy at low temperature (60 K). An efficient peridinin–chlorophyll-a energy transfer was observed. The stimulated emission signal monitored in the near-infrared spectral reg...
Excited-state properties of the carbonyl carotenoid monomeric and aggregated 8'-apo-β-carotenal were studied by means of femtosecond transient absorption spectroscopy. For 8'-apo-β-carotenal monomers, the polarity-dependent behavior characteristic of carotenoids with conjugated carbonyl group was observed. While in n-hexane the S1 lifetime of 8'-ap...
Light harvesting complexes ensure necessary flow of excitation energy into photosynthetic reaction centers. In the present work, transient absorption measurements were performed on LH1-RC complexes isolated from two aerobic anoxygenic phototrophs (AAPs), Roseobacter sp. COL2P containing the carotenoid spheroidenone, and Erythrobacter sp. NAP1 which...
We present a comparative study of xanthorhodopsin, a proton pump with the carotenoid salinixanthin serving as an antenna, and the closely related bacteriorhodopsin. Upon excitation of retinal, xanthorhodopsin exhibits a wavy transient absorption pattern in the region between 470 and 540 nm. We interpret this signal as due to electrochromic effect o...
