A5028319294- Photosynthetic Processes and Mechanisms
- Photoreceptor and optogenetics research
- Spectroscopy and Quantum Chemical Studies
- Light effects on plants
- Antioxidant Activity and Oxidative Stress
- Cardiac, Anesthesia and Surgical Outcomes
- Mitochondrial Function and Pathology
- Algal biology and biofuel production
- Respiratory Support and Mechanisms
- Anesthesia and Sedative Agents
- Anesthesia and Pain Management
- Plant Stress Responses and Tolerance
- Porphyrin and Phthalocyanine Chemistry
- Electrochemical Analysis and Applications
- Metal-Catalyzed Oxygenation Mechanisms
- Electrocatalysts for Energy Conversion
- Photochemistry and Electron Transfer Studies
- Veterinary Pharmacology and Anesthesia
- ATP Synthase and ATPases Research
- Nausea and vomiting management
- Burn Injury Management and Outcomes
- COVID-19 Clinical Research Studies
- Cardiac Arrest and Resuscitation
- Marine and coastal ecosystems
- Free Radicals and Antioxidants
Sheffield Teaching Hospitals NHS Foundation Trust
2024
Imperial College London
2005-2022
Imperial Valley College
2018
Transnational Press London
2018
Institut de Biologie et Technologies
2010
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2003-2010
Centre National de la Recherche Scientifique
2003-2010
CEA Paris-Saclay
2003-2010
Technische Universität Berlin
1998
Glasgow Royal Infirmary
1970-1991
Photosystems I and II convert solar energy into the chemical that powers life. Chlorophyll a photochemistry, using red light (680 to 700 nm), is near universal considered define "red limit" of oxygenic photosynthesis. We present biophysical studies on photosystems from cyanobacterium grown in far-red (750 nm). The few long-wavelength chlorophylls are well resolved each other majority pigment, chlorophyll a. Charge separation photosystem uses f at 745 nm (or d) 727 nm, respectively. Each has...
Singlet oxygen formation by photosystem II reaction centers isolated from Pisum sativum has been detected two chemical trapping techniques: histidine-dependent uptake and bleaching of p-nitrosodimethyl-aniline the intermediary endoperoxide histidine. The quantum yield singlet determined these methods was estimated to be 0.16 comparison with known yields standard sensitizers. formed on illumination under conditions that lead triplet state primary electron donor, P680. Experiments deuterated...
A photosystem II reaction centre has been isolated from peas and found to consist of D1, D2 polypeptides the apoproteins cytochrome b ‐559, being similar that reported for spinach by Nanba Satoh [(1987) Proc. Natl. Acad. Sci. USA 84, 109–112]. The complex binds chlorophyll a , pheophytin haem ‐559 in an approximate ratio 4:2:1 also contains about one molecule β‐carotene. It no plastoquinone‐9 or manganese but does contain at least non‐haem iron. In addition light‐induced signal due Pheo −...
During photosynthesis carotenoids normally serve as antenna pigments, transferring singlet excitation energy to chlorophyll, and preventing oxygen production from chlorophyll triplet states, by rapid spin exchange decay of the carotenoid ground state. The presence two β–carotene molecules in photosystem II reaction centre (RC) now seems well established, but they do not quench state primary electron–donor chlorophylls, which are known P 680 . β–carotenes cannot be close enough for quenching...
By measuring time-resolved luminescence emission at 1270 nm, we have detected singlet oxygen formation by illuminated, reaction centers of photosystem II isolated from Pisum sativum, which is in agreement with earlier work (Macpherson, A. N., Telfer, A., Barber, J., & Truscott, T. G. (1993) Biochim. Biophys. Acta 1143, 301-309). In this paper show that the yield significantly increased if number beta-carotene molecules bound per complex reduced two to one. We conclude, therefore, can act as...
A reaction center of photosystem II was isolated from Pisum sativum by using immobilized metal affinity chromatography. This is photochemically active and has a room temperature Qgamma chlorophyll (Chl) absorption band peaking at 677.5 nm. From HPLC analysis, the pigment stoichiometry suggested to be 5 Chls per 1 beta-carotene 2 pheophytins. Low-temperature measurements 77 K were consistent with removal one associated usual form ion-exchange Transient spectroscopy on picosecond time scale...
The electronic properties of carotenoid molecules underlie their multiple functions throughout biology, and tuning these by in vivo locus is vital importance a number cases. This exemplified photosynthetic carotenoids, which perform both light-harvesting photoprotective roles essential to the process. However, despite large scientific studies performed this field, mechanism(s) used modulate carotenoids remain elusive. We have chosen two specific cases, β-carotene photosystem II reaction...
We present a spectroscopic characterization of the two nonequivalent β-carotene molecules in photosystem II reaction center. Their electronic and vibrational properties exhibit significant differences, reflecting somewhat different configuration for these cofactors. Both carotenoid are redox-active can be oxidized by illumination centers presence an electron acceptor. The radical cation species show similar differences their properties. results discussed terms structure unusual function...