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

Structural comparisons between eukaryotic and prokaryotic PSII complexes. Jon Nield^*,1, James Barber¹, ¹ Wolfson Laboratories, London, UK

ABSTRACT- With the huge increase in structural knowledge gained from recent X-ray diffraction-derived prokaryotic photosystem II (PSII) structures, it has become possible to directly model and compare them with 3D reconstructions of eukaryotic PSII complexes obtained by electron microscopy and single particle analysis. This has allowed for conclusions to be drawn regarding the differences in known subunit composition [1] and augment the interpretation of the biological mechanisms involved. A spinach PSII 3D map has been more reliably modelled with the higher resolution data obtained from cyanobacterial PSII [2]. In addition, a Chlamydomonas reinhardtii PSII complex was included in the modelling environment and various difference mapping studies performed. Of key interest are the observed differences surrounding the oxygen-evolving complex (OEC) apparati. Funding by the BBSRC research council and The Royal Society, London, UK, is gratefully acknowledged. [1] Barber, J., and Nield, J. (2002) Phil. Trans. R. Lond. Soc. B. 357, 1329-1336 [2] Ferreira, K. N., Iverson, T.M., Maghlaoui, K., Barber, J. and Iwata, S. (2004) Science 303, 1831-1838.

KEY WORDS: Structure, 3D modelling, PSII complexes, Electron microscopy