Photosystem II (PSII) is an integral part of the photosynthesis machinery, in which several light-harvesting complexes rely on inter-complex excitonic energy transfer (EET) processes to channel energy to the reaction center. In this paper, we report on a direct observation of the inter-complex EET in a minimal PSII supercomplex from plants, containing the trimeric light-harvesting complex II (LHCII), the monomeric light-harvesting complex CP26, and the monomeric PSII core complex. Using two-dimensional (2D) electronic spectroscopy, we measure an inter-complex EET timescale of 50 picoseconds for excitations from the LHCII-CP26 peripheral antenna to the PSII core. The 2D electronic spectra also reveal that the transfer timescale is nearly constant over the pump spectrum of 600 to 700 nanometers. Structure-based calculations reveal the contribution of each antenna complex to the measured inter-complex EET time. These results provide a step in elucidating the full inter-complex energy transfer network of the PSII machinery.
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http://dx.doi.org/10.1126/sciadv.adh0911 | DOI Listing |
Methods Mol Biol
January 2025
Quantum-Si, Guilford, CT, USA.
Single-molecule fluorescence resonance energy transfer (smFRET) is a powerful technique for studying the structural dynamics of protein molecules or detecting interactions between protein molecules in real time. Due to the high sensitivity in spatial and temporal resolution, smFRET can decipher sub-populations within heterogeneous native state conformations, which are generally lost in traditional measurements due to ensemble averaging. In addition, the single-molecule reconstitution allows protein molecules to be observed for an extensive period of time and can recapitulate the geometry of the cellular environment to retain biological function.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Wuhan University, College of Chemistry and Molecular Sciences, Luojiashan Street, 430072, Wuhan, CHINA.
"Cell factory" strategy based on microbial anabolism pathways offers an intriguing alternative to relieve the dependence on fossil fuels, which are recognized as the main sources of CO2 emission. Typically, anabolism of intracellular substance in cell factory requires the consumption of sufficient reduced nicotinamide adenine dinucleotide phosphate (NADPH) and adenosine triphosphate (ATP). However, it is of great challenge to modify the natural limited anabolism and to increase the insufficient level of NADPH and ATP to optimum concentrations without causing metabolic imbalance.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Sun Yat-Sen University, School of Chemistry, 135 Xingang West, 510275, Guangzhou, CHINA.
Integrating enzymes with reticular frameworks offers promising avenues for access to functionally tailorable biocatalysis. This Minireview explores recent advances in enzyme-reticular frameworks hybrid biocomposites, focusing on the utilization of porous reticular frameworks, including metal-organic frameworks, covalent-organic frameworks, and hydrogen-bonded organic frameworks, to regulate the reactivity of an enzyme encapsulated inside mainly by pore infiltration and in situ encapsulation strategies. We highlight how pore engineering and host-guest interfacial interactions within reticular frameworks create tailored microenvironments that substantially impact the mass transfer and enzyme's conformation, leading to biocatalytic rate enhancement, or imparting enzyme with non-native biocatalytic functions including substrate-selectivity and new activity.
View Article and Find Full Text PDFJ Appl Microbiol
January 2025
School of Basic Medicine, Jiamusi University, Jiamusi 154000, China.
Aims: The aim of this study was to identify sesamin as a Casein hydrolase P (ClpP) inhibitor and to determine whether it could attenuate the virulence of methicillin-resistant Staphylococcus aureus (MRSA).
Methods And Results: Through fluorescence resonance energy transfer (FRET) screening, a natural compound sesamin demonstrated a significant inhibitory effect on ClpP enzyme activity with an IC50 of 20.62 μg/mL.
Rep Prog Phys
January 2025
Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, Aarhus, Midtjylland, 8000, DENMARK.
Irradiation of condensed matter with ionizing radiation generally causes direct photoionization as well as secondary processes that often dominate the ionization dynamics. Here, large helium (He) nanodroplets with radius ≳ 40 nm doped with lithium (Li) atoms are irradiated with extreme ultraviolet (XUV) photons of energy hν ≥ 44.4 eV and indirect ionization of the Li dopants is observed in addition to direct photoionization of the He droplets.
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