Two-photon excitation spectrum of fluorescence of the light-harvesting complex B800–850 from Allochromatium minutissimum within 1200–1500 (600–750) nm spectral range is not carotenoid mediated

Stepanenko, I. A.; Kompanets, V. O.; Чекалин, С. В.; Makhneva, Z. K.; Moskalenko, A. A.; Pishchalnikov, Roman Y.; Razjivin, A.P.

doi:10.1134/s1990747809020020

Cited by 3 publications

(5 citation statements)

References 24 publications

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“…The two-photon excitation spectrum measured by altering excitation wavelength within the range 1200–1500 nm and probing residual Q y bleaching at 10 ps delay between pump and probe pulse is shown in Figure (triangles). The spectrum is pretty much similar to the one obtained by probing the fluorescence intensity of B850 in our previous papers. , It has a wide excitation band around 1350 nm (14 800 cm –1 ). Earlier we showed that this band is a result of two-photon excitation, but is not carotenoid-mediated. , Therefore, for this investigation we used only LH2 complex from Rb.…”

Section: Resultssupporting

confidence: 80%

“…The spectrum is pretty much similar to the one obtained by probing the fluorescence intensity of B850 in our previous papers. 30,31 It has a wide excitation band around 1350 nm (14 800 cm −1 ). Earlier we showed that this band is a result of two-photon excitation, but is not carotenoid-mediated.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Earlier we showed that this band is a result of two-photon excitation, but is not carotenoid-mediated. 30,31 Therefore, for this investigation we used only LH2 complex from Rb. sphaeroides wild-type cells (carotenoid-containing).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…A clear way to distinguish the role of carotenoids in EET processes is a parallel investigation of carotenoid-containing and -depleted complexes . Recently we applied two-photon fluorescence excitation spectroscopy to LH2 complexes from purple bacteria Allochromatium minutissimum and Rhodobacter sphaeroides within 1200–1500 (600–750) nm spectral range. , It was shown that there is no difference between the two-photon fluorescence excitation spectra of LH2 complexes from All. minutissimum wild-type cells (containing carotenoids) and from cells with suppressed carotenoid synthesis.…”

Section: Introductionmentioning

confidence: 99%

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Transient Absorption Study of Two-Photon Excitation Mechanism in the LH2 Complex from Purple Bacterium Rhodobacter sphaeroides

Stepanenko

Kompanetz²,

Makhneva³

et al. 2012

J. Phys. Chem. B

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The mechanism of two-photon excitation of a peripheral light-harvesting complex LH2 (B800-850) from purple bacterium Rhodobacter sphaeroides was explained on the basis of femtosecond transient absorption data. Fast bleaching of the B850 absorption band was measured under two-photon excitation by 1350 nm femtosecond pulses, showing fast subpicosecond arrival of excitation energy to B850 circular aggregates. Any spectral changes connected with the B800 absorption band of B800-BChl molecules were absent. A similar picture was observed under one-photon excitation of the LH2 complex by 675 nm femtosecond pulses. We believe these effects may be attributed to direct excitation of high-energy excitonic states of a B850 circular aggregate or its vibrational manifold in accordance with the model of Abe [Chem. Phys. 2001, 264, 355-363].

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Section: Resultssupporting

confidence: 80%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Transient Absorption Study of Two-Photon Excitation Mechanism in the LH2 Complex from Purple Bacterium Rhodobacter sphaeroides

Stepanenko

Kompanetz²,

Makhneva³

et al. 2012

J. Phys. Chem. B

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“…Earlier we showed [ 13,21 ] that experimental spectra of two-photon fluorescence excitation of LH2 complexes within 1200-1500 nm range are not carotenoid mediated. That is why we choose the LH2 complex from Rb.…”

Section: Resultsmentioning

confidence: 99%

Photosynthetic light-harvesting complexes: fluorescent and absorption spectroscopy under two-photon (1200-1500 nm) and one-photon (600-750 nm) excitation by laser femtosecond pulses

et al. 2010

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The pathways of excitation energy transfer (EET) via pigments of the light-harvesting antenna are still in discussion. The bacteriochlorophyll fluorescence of peripheral light-harvesting complexes (LH2) from purple bacteria can be observed upon two-photon excitation (TPE) within 1200-1500 nm spectral range (a broad band near 1300 nm). Earlier the occurrence of this band was taken as an evidence for the participation of "dark" carotenoid S 1 state in EET processes (see [Walla et al., Proc. Nat. Acad. Sci. U.S.A. 97, 10808-10813 (2000)] and references in it). However we showed that TPE spectrum of LH2 fluorescence within 1200-1500 nm is not associated with carotenoids [Stepanenko et al., J. Phys. Chem. B. 113(34), 11720-11723 (2009)]. Here we present TPE spectra of fluorescence for chromatophores and lightharvesting complexes LH2 and LH1 from wild-type cells and from carotenoid-depleted or carotenoidless mutant cells of several purple bacteria. The broad band within 1300-1400 nm was found for all preparations. Absorption pump-probe femtosecond spectroscopy applied to LH2 complex from Rb. sphaeroides revealed the similar spectral and kinetic patterns for TPE at 1350 nm and one-photon excitation at 675 nm. Analysis of pigment composition of this complex by high-pressure liquid chromatography showed that even under mild isolation conditions some bacteriochlorophyll molecules were oxidized to 3-acetyl-chlorophyll molecules having the long-wavelength absorption peak in the 650-700 nm range. It is proposed that these 3-acetyl-chlorophyll molecules are responsible for the broad band in TPE spectra within the 1200-1500 nm region.

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On the biphoton excitation of the fluorescence of the bacteriochlorophyll molecules of purple photosynthetic bacteria by powerful near IR femto-picosecond pulses

Borisov

2011

J. Exp. Theor. Phys.

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Two-photon excitation spectrum of fluorescence of the light-harvesting complex B800–850 from Allochromatium minutissimum within 1200–1500 (600–750) nm spectral range is not carotenoid mediated

Cited by 3 publications

References 24 publications

Transient Absorption Study of Two-Photon Excitation Mechanism in the LH2 Complex from Purple Bacterium Rhodobacter sphaeroides

Transient Absorption Study of Two-Photon Excitation Mechanism in the LH2 Complex from Purple Bacterium Rhodobacter sphaeroides

Photosynthetic light-harvesting complexes: fluorescent and absorption spectroscopy under two-photon (1200-1500 nm) and one-photon (600-750 nm) excitation by laser femtosecond pulses

On the biphoton excitation of the fluorescence of the bacteriochlorophyll molecules of purple photosynthetic bacteria by powerful near IR femto-picosecond pulses

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