Electric field-induced absorption changes (electrochromism or Stark effect) of the light-harvesting PSII pigment-protein complexes LHCIIb, CP29, CP26 and CP24 were investigated. The results indicate the lack of strong intermolecular interactions in the chlorophyll a (Chl a) pools of all complexes. Characteristic features occur in the electronic spectrum of Chl b, which reflect the increased values of dipole moment and polarizability differences between the ground and excited states of interacting pigment systems. The strong Stark signal recorded for LHCIIb at 650-655 nm is much weaker in CP29, where it is replaced by a unique Stark band at 639 nm. Electrochromism of Chl b in CP26 and CP24 is significantly weaker but increased electrochromic parameters were also noticed for the Chl b transition at 650 nm. The spectra in the blue region are dominated by xanthophylls. The differences in Stark spectra of Chl b are linked to differences in pigment content and organization in individual complexes and point to the possibility of electron exchange interactions between energetically similar and closely spaced Chl b molecules.
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http://dx.doi.org/10.1016/j.bbabio.2004.04.004 | DOI Listing |
Int J Biol Macromol
December 2024
Engineering Research Center of Ecology and Agricultural Use of Wetland, Ministry of Education/MARA Key Laboratory of Sustainable Crop Production in the Middle Reaches of the Yangtze River (Co-construction by Ministry and Province) /Hubei Engineering Research Center for Pest Forewarning and Management/College of Agriculture, Yangtze University, Jingzhou 434025, Hubei, China. Electronic address:
The light-harvesting chlorophyll a/b-binding proteins (Lhcs) are integral to plants' capture and transfer of light energy during photosynthesis. However, the Lhc gene family remains unexplored in pepper. In this study, 37 CaLhcs (Capsicum annuum Lhc) were identified from the reference genome and classified into five subfamilies (Lhca, Lhcb, CP24, CP26, and CP29) based on phylogenetic relationships and conserved domains, with members of each subfamily displaying similar conserved motifs and gene structures.
View Article and Find Full Text PDFEcotoxicol Environ Saf
January 2023
College of Life Science, Sichuan Agricultural University, 625014 Ya'an, China. Electronic address:
Lead (Pb) pollution in the soil sub-ecosystem has been a continuously growing problem due to economic development and ever-increasing anthropogenic activities across the world. In this study, the photosynthetic performance and antioxidant capacity of Triticeae cereals (rye, wheat and triticale) were compared to assess the activities of antioxidants, the degree of oxidative damage, photochemical efficiency and the levels of photosynthetic proteins under Pb stress (0.5 mM, 1 mM and 2 mM Pb (NO)).
View Article and Find Full Text PDFJ Phycol
April 2020
Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.
Non-photochemical quenching (NPQ) is an important photoprotective mechanism in plants, which dissipates excess energy and further protects the photosynthetic apparatus under high light stress. NPQ can be dissected into a number of components: qE, qZ, and qI. In general, NPQ is catalyzed by two independent mechanisms, with the faster-activated quenching catalyzed by the monomeric light-harvesting complex (LHCII) proteins and the slowly activated quenching catalyzed by LHCII trimers, both processes depending on zeaxanthin but to different extent.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
October 2019
Department of Biophysics, Zhejiang University School of Medicine, 310058 Hangzhou, Zhejiang, China;
Photosystem II (PSII) in the thylakoid membranes of plants, algae, and cyanobacteria catalyzes light-induced oxidation of water by which light energy is converted to chemical energy and molecular oxygen is produced. In higher plants and most eukaryotic algae, the PSII core is surrounded by variable numbers of light-harvesting antenna complex II (LHCII), forming a PSII-LHCII supercomplex. In order to harvest energy efficiently at low-light-intensity conditions under water, a complete PSII-LHCII supercomplex (CSMN) of the green alga (Cr) contains more antenna subunits and pigments than the dominant PSII-LHCII supercomplex (CSM) of plants.
View Article and Find Full Text PDFEcotoxicol Environ Saf
November 2019
College of Life Sciences, Northeast Forestry University, Harbin, Heilongjiang, China. Electronic address:
In order to explore the response and adaptation mechanisms of photosynthesis of the leaves of mulberry (Morus alba L.) seedlings to saline-alkali stress. Photosynthetic activity, and the response of related proteomics of M.
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