Photosynthetic PsbR protein from higher plants

 

Jiří Heler1,2,  Marie Plevako1,2, Jost Ludwig3, Ondrej Šedo4, Zbyněk Zdrahal4, Ivana Kutá Smatanová5 and Jaroslava Kohoutová1

 

1 University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses and School of complex systems, Zámek 136, 373 33 Nové Hrady

2 University of South Bohemia in České Budějovice, Faculty of Science, Branišovská 31, 37005 České Budějovice

3University of Bonn, IZMB / Molekulare Bioenergetik, Kirschallee 1, D-53115 Bonn, Germany

4Core FacilityProteomics, CEITEC, Masaryk University, Kamenice 5,625 00 Brno

5 Academy of Sciences of the Czech Republic, Inst. of Nanobiology and Structural Biology GCRC, Zámek 136, 373 33 Nové Hrady

 

Photosynthesis is a chemical process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight [1]. Photosynthetic organisms are called photoautotrophs, since they can create their own food. In plants, algae, and cyanobacteria photosynthesis uses carbon dioxide and water, releasing oxygen as a waste product. Photosynthesis is vital for all aerobic life on the Earth. In addition to maintaining normal levels of oxygen in the atmosphere, photosynthesis is the source of energy for nearly all life on the Earth, either directly, through primary production, or indirectly, as the ultimate source of the energy [2].

Here we report identification of the primary structure of PsbR protein from Pisum sativum L. Primary and secondary structure of higher plants PsbR protein has not been discovered yet, because this protein is highly unstable outside of its normal occurrence (Photosystem II complex). The PsbR protein likes many others, which are denoted PsbAPsbZ, plays an essential role in photosynthesis of higher plants. It is a part of oxygen-evolving complex (OEC) and therefore it is directly contributing to production of oxygen.

First of all we extracted RNA from Pisum sativum L. With cDNA (from mRNA) we were capable to use it as template for the PCR reaction, where we were working with our designed degenerative primers, because as mentioned above, a complete structure of the protein has not been solved up to date. With comparison of degenerative and non-degenerative primers we were able to obtain PCR product of PsbR protein from pea that was transformed into pBluescript vector and get sequenced. To find out sequence of mature peptide the Maldi TofF spectroscopy was applied.

Simultaneously we produced psbR gene from mRNA isolated from Spinacia oleracea. Primary structure of spinach PsbR protein is known and we prepared expression vector with its anchor as HisPsbR and without anchor as PsbR. The purification conditions were optimized to get stable proteins that will be used for other structural analysis.

 

 1. Smith, A. L. (1997). Oxford dictionary of biochemistry and molecular biology. Oxford, Oxford University Press. p. 508. ISBN 0-19-854768-4. Photosynthesis – the synthesis by organisms of organic chemical compounds, esp. carbohydrates, from carbon dioxide using energy obtained from light rather than the oxidation of chemical compounds.

2. D.A. Bryant & N.-U. Frigaard (2006).Prokaryotic photosynthesis and phototrophy illuminated. Trends Microbiol 14 (11): 488–96.

 

This research was supported by the ME CR (COST LD11011, ME09016, CZ.1.05/2.1.00/01.0024), GACR (P207/12/0775, P207/11/0717), by the AS CR (AV0Z60870520) and GAJU 170/2010/P for name of students.