Spectral shift mechanisms of chlorophylls in liquids and proteins

Renge, Indrek; Mauring, Koit

doi:10.1016/j.saa.2012.10.034

Cited by 39 publications

(61 citation statements)

References 101 publications

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“…These energies were computed by using the same QC methods as used for the determination of the atomic partial charges. The vertical S 0 → S 1 transition energy of Chl a in vacuum can be estimated to 2.0 eV taking into account solvent effects [83] and Huang-Rhys factors [84].…”

Section: Calculation Of Site Energiesmentioning

confidence: 99%

The quest for energy traps in the CP43 antenna of photosystem II

Müh

Plöckinger

Ortmayer

et al. 2015

Journal of Photochemistry and Photobiology B: Biology

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Section: Calculation Of Site Energiesmentioning

confidence: 99%

The quest for energy traps in the CP43 antenna of photosystem II

Müh

Plöckinger

Ortmayer

et al. 2015

Journal of Photochemistry and Photobiology B: Biology

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“…These have been neatly summarized in a recent review. 8 A combination of these factors gives rise to quite marked shifts in the electronic spectra of chlorophylls when they are incorporated into a protein matrix. 3 How these protein-pigment interactions might modulate 2DES is not immediately clear, thus it is important to characterize the effect of the medium on the 2DES of chlorophylls, which is the main objective of the work described here.…”

Section: Introductionmentioning

confidence: 99%

Two-Dimensional Electronic Spectroscopy of Chlorophyll a: Solvent Dependent Spectral Evolution

2015

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The interaction of the monomeric chlorophyll Q band electronic transition with solvents of differing physical-chemical properties is investigated through two-dimensional electronic spectroscopy (2DES). Chlorophyll constitutes the key chromophore molecule in light harvesting complexes. It is well known that the surrounding protein in the light harvesting complex fine tunes chlorophyll electronic transitions to optimize energy transfer. Therefore an understanding of the influence of the environment on the monomeric chlorophyll electronic transitions is important. The Q band 2DES are inhomogeneous at early times, particularly in hydrogen bonding polar solvents, but also in nonpolar solvents like cyclohexane. Interestingly this inhomogeneity persists for long times, even up to the nanosecond timescale in some solvents. The reshaping of the 2DES occurs over multiple timescales and was assigned mainly to spectral diffusion. At early times the reshaping is Gaussianlike, hinting at a strong solvent reorganization effect. The temporal evolution of the 2DES response was analysed in terms of a Brownian oscillator model. The spectral densities underpinning the Brownian oscillator fitting were recovered for the different solvents. The absorption spectra and Stokes shift were also properly described by this model. The extent and nature of inhomogeneous broadening was a strong function of solvent, being larger in H-bonding and viscous media and smaller in nonpolar solvents. The fastest spectral reshaping components were assigned to solvent dynamics, modified by interactions with the solute.

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“…The extra shift that cannot be accounted for by the specific point mutation may be attributed to a non-specific solvatochromic effect. [5b, 16] It is reasonable to assume that the slight variations in protein structure lead to global non-specific difference between CaWSCP and LvWSCP. These vary the local dielectric constant and refractive index around the Chl in each protein, which eventually lead to spectral band shifts.…”

mentioning

confidence: 99%

“…These vary the local dielectric constant and refractive index around the Chl in each protein, which eventually lead to spectral band shifts. [16b] The mutation S 84 ->A in CaWSCP led a minor shift of the Qy band to 671 nm, whereas the reciprocal mutation A 87 ->S in LvWSCP did not have any effect on the Qy band position. This confirms our assumption that this change of polarity by itself is too small to significantly affect the Chl spectra.…”

mentioning

confidence: 99%

Fine Tuning of Chlorophyll Spectra by Protein‐Induced Ring Deformation

et al. 2016

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The ability to tune the light-absorption properties of chlorophylls by their protein environment is the key to the robustness and high efficiency of photosynthetic light-harvesting proteins. Unfortunately, the intricacy of the natural complexes makes it very difficult to identify and isolate specific protein-pigment interactions that underlie the spectral-tuning mechanisms. Herein we identify and demonstrate the tuning mechanism of chlorophyll spectra in type II water-soluble chlorophyll binding proteins from Brassicaceae (WSCPs). By comparing the molecular structures of two natural WSCPs we correlate a shift in the chlorophyll red absorption band with deformation of its tetrapyrrole macrocycle that is induced by changing the position of a nearby tryptophan residue. We show by a set of reciprocal point mutations that this change accounts for up to 2/3 of the observed spectral shift between the two natural variants.

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Spectral shift mechanisms of chlorophylls in liquids and proteins

Cited by 39 publications

References 101 publications

The quest for energy traps in the CP43 antenna of photosystem II

The quest for energy traps in the CP43 antenna of photosystem II

Two-Dimensional Electronic Spectroscopy of Chlorophyll a: Solvent Dependent Spectral Evolution

Fine Tuning of Chlorophyll Spectra by Protein‐Induced Ring Deformation

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