Abstract
We studied the periodicity of the multilamellar membrane system of granal chloroplasts in different isolated plant thylakoid membranes, using different suspension media, as well as on different detached leaves and isolated protoplasts - using small-angle neutron scattering. Freshly isolated thylakoid membranes suspended in isotonic or hypertonic media, containing sorbitol supplemented with cations, displayed Bragg peaks typically between 0.019 and 0.023 Å- 1, corresponding to spatially and statistically averaged repeat distance values of about 275-330 Å. Similar data obtained earlier led us in previous work to propose an origin from the periodicity of stroma thylakoid membranes. However, detached leaves, of eleven different species, infiltrated with or soaked in D2O in dim laboratory light or transpired with D2O prior to measurements, exhibited considerably smaller repeat distances, typically between 210 and 230 Å, ruling out a stromal membrane origin. Similar values were obtained on isolated tobacco and spinach protoplasts. When NaCl was used as osmoticum, the Bragg peaks of isolated thylakoid membranes almost coincided with those in the same batch of leaves and the repeat distances were very close to the electron microscopically determined values in the grana. Although neutron scattering and electron microscopy yield somewhat different values, which is not fully understood, we can conclude that small-angle neutron scattering is a suitable technique to study the periodic organization of granal thylakoid membranes in intact leaves under physiological conditions and with a time resolution of minutes or shorter. We also show here, for the first time on leaves, that the periodicity of thylakoid membranes in situ responds dynamically to moderately strong illumination. This article is part of a Special Issue entitled: Photosynthesis research for sustainability: Keys to produce clean energy.
| Original language | English |
|---|---|
| Pages (from-to) | 1572-1580 |
| Number of pages | 9 |
| Journal | Biochimica et Biophysica Acta - Bioenergetics |
| Volume | 1837 |
| Issue number | 9 |
| DOIs | |
| State | Published - Sep 2014 |
| Externally published | Yes |
Funding
We would like to thank the Budapest Neutron Center (BNC), Budapest, Hungary; Institute Laue-Langevin (ILL), Grenoble, France; Paul Scherrer Institute (PSI), Villigen, Switzerland; Jülich Centre for Neutron Science (JCNS), Garching, Germany for providing us beamtime for the SANS experiments. This research project has been supported by the European Commission under the 7th Framework Programme through the ‘Research Infrastructures’ action of the ‘Capacities’ Programme, NMI3-II Grant number 283883 . The authors are indebted to Prof. Ziv Reich for many helpful discussions and to Dr. Onie Tsabari (Weizmann Institute of Science, Rehovot Israel) for providing us protoplasts isolated from spinach leaves. The authors are grateful to Csilla Gergely (Eötvös University, Budapest) for skillful technical assistance with the EM sample preparation, and to Drs. Kitti Sipos and Márton Markó for performing one of the SANS measurements. We are indebted to Dr. László Almásy and Gergely Eszenyi for helping us configuring some experiments at the PSI. We also would like to thank Dr. Joachim Kohlbrecher for his help in our measurements performed at the SANS-I instrument. We are also grateful to Prof. P. Laggner and Dr. H. Amenitsch for the possibility of carrying out experiments at the Austrian SAXS beamline at ELETTRA (Triest, Italy). This work was supported by the Marie Curie Initial Training Network “HARVEST” sponsored by the 7th Framework Program of the European Union (grant number 238017 , to G.G.), the Hungarian Scientific Research Fund/National Office for Research and Technology (grant number 60003-00 (previously 80341 and 80345) (to L.R. and G.G.)), the National Office for Research and Technology (grant number NAP-VENEUS05 (to L.R.)). Partial support was also obtained from the Hungarian Scientific Research Fund ( OTKA-PD 104530 to P.H.L.), and from the Hungarian National Innovation Office and A*STAR Singapore ( NIH-A*STAR TET_10-1-2011-0279 to G.G.). D.P. thanks DANSCATT (Danish Centre for the use of Synchrotron X-ray and Neutron facilities) for financial support.
| Funders | Funder number |
|---|---|
| 7th Framework Program | |
| 7th Framework Programme | 283883 |
| Danish Centre | |
| Hungarian National Innovation Office | |
| Hungarian Scientific Research Fund/National Office for Research and Technology | 80341, 80345, 60003-00 |
| NIH-A | *STAR TET_10-1-2011-0279 |
| European Commission | 238017 |
| Agency for Science, Technology and Research | |
| Hungarian Scientific Research Fund | OTKA-PD 104530 |
| Nemzeti Kutatási és Technológiai Hivatal | NAP-VENEUS05 |
| DanScatt |
Keywords
- Electron microscopy
- Granum
- Lamellar repeat distance
- Small-angle neutron scattering
- Thylakoid membrane
