scholarly journals New Insights in Thylakoid Membrane Organization

2005 ◽  
Vol 46 (9) ◽  
pp. 1443-1451 ◽  
Author(s):  
Stephan Pfeiffer ◽  
Karin Krupinska
Keyword(s):  
Thylakoid Membrane ◽  
Membrane Organization

A Thylakoid-Located Two-Pore K+ Channel Controls Photosynthetic Light Utilization in Plants

Science ◽  
2013 ◽  
Vol 342 (6154) ◽  
pp. 114-118 ◽  
Author(s):  
Luca Carraretto ◽  
Elide Formentin ◽  
Enrico Teardo ◽  
Vanessa Checchetto ◽  
Martino Tomizioli ◽  
...  
Keyword(s):  
Thylakoid Membrane ◽  
Proton Motive Force ◽  
Motive Force ◽  
K Channel ◽  
Channel Activity ◽  
Membrane Organization ◽  
Physiological Functions ◽  
Environmental Stimuli ◽  
Light Utilization ◽  
Selective Channel

The size of the light-induced proton motive force (pmf) across the thylakoid membrane of chloroplasts is regulated in response to environmental stimuli. Here, we describe a component of the thylakoid membrane, the two-pore potassium (K+) channel TPK3, which modulates the composition of the pmf through ion counterbalancing. Recombinant TPK3 exhibited potassium-selective channel activity sensitive to Ca2+ and H+. In Arabidopsis plants, the channel is found in the thylakoid stromal lamellae. Arabidopsis plants silenced for the TPK3 gene display reduced growth and altered thylakoid membrane organization. This phenotype reflects an impaired capacity to generate a normal pmf, which results in reduced CO2 assimilation and deficient nonphotochemical dissipation of excess absorbed light. Thus, the TPK3 channel manages the pmf necessary to convert photochemical energy into physiological functions.

scholarly journals Influence of the compatible solute sucrose on thylakoid membrane organization and violaxanthin de-epoxidation

Planta ◽  
2021 ◽  
Vol 254 (3) ◽  
Author(s):  
Reimund Goss ◽  
Christian Schwarz ◽  
Monique Matzner ◽  
Christian Wilhelm
Keyword(s):  
Thylakoid Membrane ◽  
Higher Plants ◽  
Thylakoid Membranes ◽  
Compatible Solute ◽  
In Vitro Assays ◽  
Lipid Phase ◽  
Enzyme Assays ◽  
Membrane Organization ◽  
Lipid Organization

Abstract Main conclusion The compatible solute sucrose reduces the efficiency of the enzymatic de-epoxidation of violaxanthin, probably by a direct effect on the protein parts of violaxanthin de-epoxidase which protrude from the lipid phase of the thylakoid membrane. The present study investigates the influence of the compatible solute sucrose on the violaxanthin cycle of higher plants in intact thylakoids and in in vitro enzyme assays with the isolated enzyme violaxanthin de-epoxidase at temperatures of 30 and 10 °C, respectively. In addition, the influence of sucrose on the lipid organization of thylakoid membranes and the MGDG phase in the in vitro assays is determined. The results show that sucrose leads to a pronounced inhibition of violaxanthin de-epoxidation both in intact thylakoid membranes and the enzyme assays. In general, the inhibition is similar at 30 and 10 °C. With respect to the lipid organization only minor changes can be seen in thylakoid membranes at 30 °C in the presence of sucrose. However, sucrose seems to stabilize the thylakoid membranes at lower temperatures and at 10 °C a comparable membrane organization to that at 30 °C can be observed, whereas control thylakoids show a significantly different membrane organization at the lower temperature. The MGDG phase in the in vitro assays is not substantially affected by the presence of sucrose or by changes of the temperature. We conclude that the presence of sucrose and the increased viscosity of the reaction buffers stabilize the protein part of the enzyme violaxanthin de-epoxidase, thereby decreasing the dynamic interactions between the catalytic site and the substrate violaxanthin. This indicates that sucrose interacts with those parts of the enzyme which are accessible at the membrane surface of the lipid phase of the thylakoid membrane or the MGDG phase of the in vitro enzyme assays.

Subfractional Analysis of Thylakoid Membrane Organization and Adaptation

1989 ◽  
pp. 511-521
Author(s):  
Bertil Andersson ◽  
Ulla K. Larsson ◽  
Cecilia Sundby ◽  
Pirkko Mäenpää ◽  
Sophie Bingsmark ◽  
...  
Keyword(s):  
Thylakoid Membrane ◽  
Membrane Organization
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