Related Experiment Video
Updated: Aug 8, 2026
08:04
A New Approach for the Comparative Analysis of Multiprotein Complexes Based on 15N Metabolic Labeling and Quantitative Mass Spectrometry
Published on: March 13, 2014
Focus on the aggregation processes of Photosystem II complexes
A Ventrella1, L Catucci, V Villari
1Dipartimento di Chimica, Universita' di Bari, Via Orabona 4, 70126 Bari, Italy.
Bioelectrochemistry (Amsterdam, Netherlands)
|May 30, 2006
Summary
Temperature and n-dodecyl-beta-d-maltoside (DM) affect Photosystem II (PSII) complex organization. Low DM concentrations induce PSII aggregation, reducing photoactivity, but higher DM concentrations reverse this aggregation.
Area of Science:
- Biochemistry
- Biophysics
- Photosynthesis Research
Background:
- Photosystem II (PSII) is crucial for oxygenic photosynthesis.
- Understanding PSII complex organization is key to elucidating its function.
- Environmental factors like temperature and detergent concentration can influence protein structure and aggregation.
Purpose of the Study:
- To investigate the impact of temperature and n-dodecyl-beta-d-maltoside (DM) on the organization of Photosystem II (PSII) complexes.
- To characterize the aggregation process of PSII monomers and dimers under varying conditions.
- To assess the photoactivity changes of PSII during aggregation and the reversibility of this process.
Main Methods:
- Steady-state fluorescence spectroscopy
- Absorption spectroscopy
- Circular dichroism (CD) spectroscopy
- Rayleigh light scattering
- Dynamic light scattering (DLS)
- Oxygen evolution measurements
Main Results:
- PSII monomer and dimer aggregation was observed at different temperatures and low DM concentrations.
- Aggregation led to a measurable decrease in PSII photoactivity (oxygen evolution).
- Increasing DM concentration effectively reversed the observed aggregation process.
Conclusions:
- Temperature and DM concentration significantly influence PSII complex organization and aggregation.
- PSII aggregation, induced by low DM, impairs its photosynthetic activity.
- The aggregation process is reversible by increasing DM concentration, suggesting a dynamic structural regulation mechanism.
Related Concept Videos
01:22Photosystem II
The multi-protein complex photosystem II (PS II) harvests photons and transfers their energy through its bound pigments to its reaction center, and ultimately to photosystem I (PSI) through the electron transport chain. The pigments responsible for caputirng the light energy in photosystems include chlorophyll a, chlorophyll b, and carotenoids.
The pigment molecules are arranged across two photosystem domains — the antenna complex and the reaction center. The main aim of the pigment molecules...
The pigment molecules are arranged across two photosystem domains — the antenna complex and the reaction center. The main aim of the pigment molecules...
01:32Photosystems
Photosystems are multiprotein complexes that form the functional units of photosynthesis in plants, algae, and cyanobacteria. They are found embedded in the membrane of tiny sac-like structures called thylakoids placed inside the chloroplast.
Functioning of Photosystems
Photosystems contain many pigment molecules, such as chlorophylls and carotenoids, arranged in a particular organization across two domains — the antenna complex and the reaction center. The main aim of the pigment molecules...
Functioning of Photosystems
Photosystems contain many pigment molecules, such as chlorophylls and carotenoids, arranged in a particular organization across two domains — the antenna complex and the reaction center. The main aim of the pigment molecules...
01:27Photosystem I
Although structurally similar to photosystem II (PSII), photosystem I (PSI) is has a different electron supplier and electron acceptor.
Both these photosystems work in concert. An excited electron from PSII is relayed to PSI via an electron transport chain in the thylakoid membrane of the chloroplast, which is comprised of the carrier molecule plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As electrons move between PSII and PSI, they lose energy and must be re-energized...
Both these photosystems work in concert. An excited electron from PSII is relayed to PSI via an electron transport chain in the thylakoid membrane of the chloroplast, which is comprised of the carrier molecule plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As electrons move between PSII and PSI, they lose energy and must be re-energized...
01:29The Photochemical Reaction Center
Reaction centers are pigment-protein complexes that initiate energy conversion from photons to chemical entities. Therefore, photochemical reaction center is a more appropriate term that describes these complexes. The Nobel laureates Robert Emerson and William Arnold provided the first experimental evidence of photochemical reaction centers by demonstrating the participation of nearly 2,500 chlorophyll molecules for the release of just one molecule of oxygen. Despite thousands of photosynthetic...
01:15The Antenna Complex
Plants and other photosynthetic organisms comprise pigments capable of absorption of direct sunlight. These pigments are present in the reaction center - the main site of photochemical reactions as well as in the antenna complex. Under average light conditions, the rate at which reaction center pigments absorb light is far below the electron transport chain's capacity. As a result, the reaction center alone cannot provide enough energy to drive photosynthesis. The photosynthetic efficiency can...
01:34The Z-Scheme of Electron Transport in Photosynthesis
The light reactions of photosynthesis assume a linear flow of electrons from water to NADP+. During this process, light energy drives the splitting of water molecules to produce oxygen. However, oxidation of water molecules is a thermodynamically unfavorable reaction and requires a strong oxidizing agent. This is accomplished by the first product of light reactions: oxidized P680 (or P680+), the most powerful oxidizing agent known in biology. The oxidized P680 that acquires an electron from the...