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Title: Evidence for a cysteine-mediated mechanism of excitation energy regulation in a photosynthetic antenna complex

Authors:
; ; ; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1258715
Grant/Contract Number:
SC0001035
Resource Type:
Journal Article: Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 113; Journal Issue: 31; Related Information: CHORUS Timestamp: 2017-06-24 12:56:19; Journal ID: ISSN 0027-8424
Publisher:
Proceedings of the National Academy of Sciences
Country of Publication:
United States
Language:
English

Citation Formats

Orf, Gregory S., Saer, Rafael G., Niedzwiedzki, Dariusz M., Zhang, Hao, McIntosh, Chelsea L., Schultz, Jason W., Mirica, Liviu M., and Blankenship, Robert E. Evidence for a cysteine-mediated mechanism of excitation energy regulation in a photosynthetic antenna complex. United States: N. p., 2016. Web. doi:10.1073/pnas.1603330113.
Orf, Gregory S., Saer, Rafael G., Niedzwiedzki, Dariusz M., Zhang, Hao, McIntosh, Chelsea L., Schultz, Jason W., Mirica, Liviu M., & Blankenship, Robert E. Evidence for a cysteine-mediated mechanism of excitation energy regulation in a photosynthetic antenna complex. United States. doi:10.1073/pnas.1603330113.
Orf, Gregory S., Saer, Rafael G., Niedzwiedzki, Dariusz M., Zhang, Hao, McIntosh, Chelsea L., Schultz, Jason W., Mirica, Liviu M., and Blankenship, Robert E. 2016. "Evidence for a cysteine-mediated mechanism of excitation energy regulation in a photosynthetic antenna complex". United States. doi:10.1073/pnas.1603330113.
@article{osti_1258715,
title = {Evidence for a cysteine-mediated mechanism of excitation energy regulation in a photosynthetic antenna complex},
author = {Orf, Gregory S. and Saer, Rafael G. and Niedzwiedzki, Dariusz M. and Zhang, Hao and McIntosh, Chelsea L. and Schultz, Jason W. and Mirica, Liviu M. and Blankenship, Robert E.},
abstractNote = {},
doi = {10.1073/pnas.1603330113},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
number = 31,
volume = 113,
place = {United States},
year = 2016,
month = 6
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1073/pnas.1603330113

Citation Metrics:
Cited by: 8works
Citation information provided by
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  • Plasmonic metal nanoparticles enhance chemical reactions on their surface when illuminated with light of particular frequencies. It has been shown that these processes are driven by excitation of localized surface plasmon resonance (LSPR). The interaction of LSPR with adsorbate orbitals can lead to the injection of energized charge carriers into the adsorbate, which can result in chemical transformations. The mechanism of the charge injection process (and role of LSPR) is not well understood. Here we shed light on the specifics of this mechanism by coupling optical characterization methods, mainly wavelength-dependent Stokes and anti-Stokes SERS, with kinetic analysis of photocatalytic reactionsmore » in an Ag nanocube–methylene blue plasmonic system. We propose that localized LSPR-induced electric fields result in a direct charge transfer within the molecule–adsorbate system. Lastly, these observations provide a foundation for the development of plasmonic catalysts that can selectively activate targeted chemical bonds, since the mechanism allows for tuning plasmonic nanomaterials in such a way that illumination can selectively enhance desired chemical pathways.« less
  • One- and two-color pump/probe femtosecond and hole-burning data are reported for the isolated B800-850 (LH2) antenna complex of Rhodopseudomonas acidophila (strain 10050). The two-color profiles are interpretable in terms of essentially monophasic B800{yields}B850 energy transfer with kinetics ranging from 1.6 to 1.1 ps between 19 and 130 K for excitation at or to the red of the B800 absorption maximum. The B800 zero-phonon hole profiles obtained at 4.2 K with burn frequencies located near or to the red of this maximum yielded a transfer time of 1.8 ps. B800 hole-burning data (4.2 K) are also reported for chromatophores at ambientmore » pressure and pressures of 270 and 375 MPa. At ambient pressure the B800-B850 energy gap is 950 cm{sup -1}, while at 270 and 375 MPa it is close to 1000 and 1050 cm{sup -1}, respectively. However, no dependence of the B800{yields}B850 transfer time on pressure was observed. The resilience of the transfer rate to pressure-induced changes in the energy gap and the weak temperature dependence of the rate are consistent with the model that has the spectral overlap (of Foerster theory) provided by the B800 fluorescence origin band and weak vibronic absorption bands of B850. However, both the time domain and hole-burning data establish that there is an additional relaxation channel for B800, which is observed when excitation is located to the blue of the B800 absorption maximum. 40 refs., 11 figs., 6 tabs.« less
  • Spheroidene and a series of spheroidene analogues with extents of p-electron conjugation ranging from 7 to 13 carbon-carbon double bonds were incorporated into the B850 light-harvesting complex of Rhodobacter sphaeroides R-26.1. The structures and spectroscopic properties of the carotenoids and the dynamics of energy transfer from the carotenoid to bacteriochlorophyll (BChl) in the B850 complex were studied by using steady-state absorption, fluorescence, fluorescence excitation, resonance Raman, and time-resolved absorption spectroscopy. The spheroidene analogues used in this study were 5',6'-dihydro-7',8'-didehydrospheroidene, 7',8'-didehydrospheroidene, and 1',2'-dihydro-3',4',7',8'-tetradehydrospheroidene. These data, taken together with results from 3,4,7,8-tetrahydrospheroidene, 3,4,5,6-tetrahydrospheroidene, 3,4-dihydrospheroidene, and spheroidene already published (Frank, H. A.; Farhoosh,more » R.; Aldema, M. L.; DeCoster, B.; Christensen, R. L.; Gebhard, R.; Lugtenburg, J. Photochem. Photobiol. 1993, 57, 49. Farhoosh, R.; Chynwat, V.; Gebhard, R.; Lugtenburg, J.; Frank, H. A. Photosynth. Res. 1994, 42, 157), provide a systematic series of molecules for understanding the molecular features that determine the mechanism of energy transfer from carotenoids to BChl in photosynthetic bacterial light-harvesting complexes. The data support the hypothesis that only carotenoids having 10 or less carbon-carbon double bonds transfer energy via their 21Ag (S1) states to BChl to any significant degree. Energy transfer via the 11Bu (S2) state of the carotenoid becomes more important than the S1 route as the number of conjugated carbon-carbon double bonds increases. The results also suggest that the S2 state associated with the Qx transition of the B850 BChl is the most likely acceptor state for energy transfer originating from both the 2{sup 1}A{sub g} (S{sub 1}) and 1{sup 1}B{sub u} (S{sub 2}) states of all carotenoids.« less
  • The photosynthetic antenna of Chloroflexus aurantiacus includes bacteriochlorophyll (BChl) c/sub 740/ and BChl a/sub 292/, both of which occur in chlorosomes, and B808-866 (containing BChl a/sub 808/ and BChl a/sub 866/), which is membrane-located (subscripts refer to near-infrared absorption maxima in vivo). BChl a/sub 792/ is thought to mediate excitation transfer from BChl c/sub 740/ to BChl a/sub 808/. Lifetimes of fluorescence from BChl c/sub 792/ and BChl a/sub 792/ were measured in isolated and membrane-bound chlorosomes in order to study energy transfer from these pigments. In both preparations, the lifetime of BChl c/sub 740/ fluorescence was at or belowmore » the instrumental limit of temporal resolution (about 30-50 ps), implying extremely fast excitation transfer from this pigment. Attempts to disrupt excitation transfer from BChl c/sub 740/, either by conversion of part of this pigment to a monomeric form absorbing at 671 nm or by partial destruction of BChl a/sub 792/ by oxidation with K/sub 3/Fe(CN)/sub 6/, had no discernible effects on the lifetime of BChl c/sub 740/ fluorescence. Most of the fluorescence from BChl a/sub 792/ decayed with a lifetime of 93 +/- 21 ps in membrane-attached chlorosomes and 155 +/- 22 ps in isolated chlorosomes at room temperature. Assuming that the only difference between these preparations is the occurrence of excitation transfer from BChl a/sub 792/ to B808-866, a 41% efficiency was calculated for this process. These results imply either that BChl a/sub 792/ is not an obligatory intermediate in energy transfer from BChl c/sub 7/$/sub 0/ to B808-866 or (more probably) that chlorosome isolation introduces new processes for quenching fluorescence from BChl a/sub 792/.« less