Displacement of particles from the purified light-harvesting chlorophyll a/b protein aggregate (LHC) was studied in magnetic fields of various strengths (0 to 1.6 T) by polarized fluorescence measurements. Macromolecular aggregates of LHC have a considerable magnetic susceptibility which enables the particles to rotate and align with their nematic axes parallel with H. As LHC is embedded in a transmembrane direction thylakoids should align perpendicular to H, the mode of alignment experimentally observed in thylakoids. The value of the magnetic susceptibility could be estimated by relating it to the integral susceptibility of the chlorophyll molecules in LHC. The fitting of this value with the field strength dependency of the fluorescence polarization ratio (FP) revealed a relationship between the LHC content of various photosynthetic membranes and their capacity for alignment, which suggested that LHC might be the torque ordering chloroplasts in a magnetic field.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1007/BF00118286 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Biochemical evidence for the diversity of LHCI proteins in PSI-LHCI from the red alga Galdieria sulphuraria NIES-3638.
Photosynth Res
January 2025
Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan.
Red algae are photosynthetic eukaryotes whose light-harvesting complexes (LHCs) associate with photosystem I (PSI). In this study, we examined characteristics of PSI-LHCI, PSI, and LHCI isolated from the red alga Galdieria sulphuraria NIES-3638. The PSI-LHCI supercomplexes were purified using anion-exchange chromatography followed by hydrophobic-interaction chromatography, and finally by trehalose density gradient centrifugation.
View Article and Find Full Text PDFAn Unexpected Water Channel in the Light-Harvesting Complex of a Diatom: Implications for the Switch between Light Harvesting and Photoprotection.
ACS Phys Chem Au
January 2025
School of Science, Constructor University, Campus Ring 1, 28759 Bremen, Germany.
Many important processes in cells depend on the transfer of protons through water wires embedded in transmembrane proteins. Herein, we have performed more than 55 μs all-atom simulations of the light-harvesting complex of a diatom, i.e.
View Article and Find Full Text PDFSeed pretreatment with cloquintocet-mexyl protects wheat seedlings from fomesafen injury by promoting photosynthesis and decreasing oxidative stress.
Pest Manag Sci
January 2025
College of Resources and Environment, Henan Institute of Science and Technology, Xinxiang, China.
Background: Fomesafen is a selective herbicide widely used to control post-emergent broad-leaf weeds in soybean and peanut fields. Because of its persistent nature in soil, it can suppress subsequent crops, including wheat. There is limited information focusing on methods of protecting wheat from fomesafen injury by soil residue.
View Article and Find Full Text PDFThe Q-Band Energetics and Relaxation of Chlorophylls and as Revealed by Visible-to-Near Infrared Time-Resolved Absorption Spectroscopy.
J Phys Chem Lett
January 2025
Key Laboratory of Advanced Light Conversion Materials and Biophotonics, School of Chemistry and Life Resources, Renmin University of China, Beijing 100872, P. R. China.
Chlorophyll (Chl) is the most abundant light-harvesting pigment of oxygenic photosynthetic organisms; however, the Q-band energetics and relaxation dynamics remain unclear. In this work, we have applied femtosecond time-resolved (-TA) absorption spectroscopy in 430-1,700 nm to Chls and in diluted pyridine solutions under selective optical excitation within their Q-bands. The results revealed distinct near-infrared absorption features of the B ← Q and B ← Q transitions in 930-1,700 nm, which together with the steady-state absorption in 400-700 nm unveiled the Q-state energy that lies 1,000 ± 400 and 600 ± 400 cm above the Q-state for Chls and , respectively.
View Article and Find Full Text PDFKey Chlorophyll Molecules in the Uphill Energy Transfer from Chlorophyll to P700 in Far-Red Light-Adapted Photosystem I.
J Phys Chem B
January 2025
Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
Multiple far-red light-adapted photosystem I (FR-PSI) reaction centers are recently found to work in oxygenic photosynthesis. They contain a small amount of a new type pigment chlorophyll (Chl ) in addition to the major pigment chlorophyll (Chl ). FR-PSI differs from the conventional PSIs in plants and cyanobacteria, which use only visible light absorbed by Chl , although the mechanism of FR-PSI is not fully clear yet.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!