PARENT SESSION
Posters P5A Type II reaction centres : Structure. Abstracts (289-312)

Single particle image analysis studies on Chlamydomonas reinhardtii PSII mutants. Heredia Pedro^*,1, Barber James¹, Nield Jon¹, ¹ Dept Biol Sci, London, UK

ABSTRACT- Photosystem two (PSII) mutants of the eukaryotic green alga Chlamydomonas reinhardtii, one incorporating His-tagged PsbH (a kind gift from Professor J. Nugent, University College London), the other perturbed in the oxygen-evolving complex, a PsbP-deficient mutant FUD39 (from the Chlamydomonas Genetics Center), were both cultured and LHCII-PSII supercomplexes isolated in the laboratory with the view to achieving comparative structural studies by electron microscopy / single particle analysis. The His-tagged mutant allowed for a high degree of purification to be achieved via Nickel-chelate affinity chromatography. Initial studies on negatively stained samples imaged under the electron microscope allowed for difference maps to be obtained from various three-dimensional (3D) reconstructions. All reconstructions have been interpreted with respect to the latest high-resolution PSII dimer studies in the literature, obtained from X-ray crystallography, and modeling studies performed, albeit that the latter X-ray studies are derived from cyanobacterial samples.

KEY WORDS: Electron Microscopy, Photosystem II, Single particle analises