Photosynthetic organisms rapidly adjust the capture, transfer and utilization of light energy to optimize the efficiency of photosynthesis and avoid photodamage. These adjustments involve fine‐tuning of expression levels and mutual interactions among electron/proton transfer components and their associated light‐harvesting antenna. Detailed studies of these interactions and their dynamics have been hindered by the low throughput and resolution of currently available research tools, which involve laborious isolation, separation and characterization steps. To address these issues, we developed an approach that measured multiple spectroscopic properties of thylakoid preparations directly in native polyacrylamide gel electrophoresis gels, enabling unprecedented resolution of photosynthetic complexes, both in terms of the spectroscopic and functional details, as well as the ability to distinguish separate complexes and thus test their functional connections. As a demonstration, we explore the thylakoid membrane components of
This content will become publicly available on August 17, 2024
Light energy is essential for the existence of life on this planet, and only photosynthetic organisms, equipped with light-harvesting antenna protein complexes, can capture this energy, making it readily accessible to all other life forms. However, these light-harvesting antennae are not designed to function optimally under extreme high light, a condition which can cause photodamage and significantly reduce photosynthetic productivity.
more » « less- Award ID(s):
- 2037887
- NSF-PAR ID:
- 10492391
- Editor(s):
- Denef, Vincent J.
- Publisher / Repository:
- ASM Journals
- Date Published:
- Journal Name:
- Microbiology Spectrum
- Volume:
- 11
- Issue:
- 4
- ISSN:
- 2165-0497
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Excitation energy transfer (EET) determines the fate of sunlight energy absorbed by light‐harvesting proteins in natural photosynthetic systems and photovoltaic cells. As previously reported (D. Kosenkov,
J. Comput. Chem . 2016, 37(19), 1847),PyFREC software enables computation of electronic couplings between organic molecules with a molecular fragmentation approach. The present work reports implementation of direct fragmentation‐based computation of the electronic couplings and EET rates in pigment–protein complexes within the Förster theory inPyFREC . The new feature enables assessment of EET pathways in a wide range of photosynthetic complexes, as well as artificial molecular architectures that include light‐harvesting proteins or tagged fluorescent biomolecules. The developed methodology has been tested analyzing EET in the Fenna–Matthews–Olson (FMO) pigment–protein complex. The pathways of excitation energy transfer in FMO have been identified based on the kinetics studies. © 2017 Wiley Periodicals, Inc. -
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Abstract Two water‐soluble zinc(II) phthalocyanines substituted with two or four permethylated
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We present a theoretical study of quantum coherent dynamics of a three-level Λ-system driven by a thermal environment (such as blackbody radiation), which serves as an essential building block of photosynthetic light-harvesting models and quantum heat engines. By solving nonsecular Bloch–Redfield master equations, we obtain analytical results for the ground-state population and coherence dynamics and classify the dynamical regimes of the incoherently driven Λ-system as underdamped and overdamped depending on whether the ratio Δ/[ rf( p)] is greater or less than one, where Δ is the ground-state energy splitting, r is the incoherent pumping rate, and f( p) is a function of the transition dipole alignment parameter p. In the underdamped regime, we observe long-lived coherent dynamics that lasts for τ c ≃ 1/ r, even though the initial state of the Λ-system contains no coherences in the energy basis. In the overdamped regime for p = 1, we observe the emergence of coherent quasi-steady states with the lifetime τ c = 1.34( r/Δ 2 ), which have a low von Neumann entropy compared to conventional thermal states. We propose an experimental scenario for observing noise-induced coherent dynamics in metastable He* atoms driven by x-polarized incoherent light. Our results suggest that thermal excitations can generate experimentally observable long-lived quantum coherent dynamics in the ground-state subspace of atomic and molecular Λ-systems in the absence of coherent driving.more » « less
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