Crystallization of higher plant photosystem II

Olga Shmidt

Institute of Physical Biology, University of South Bohemia, CZ‑373 33 Nové Hrady

The aim of this work carried out in collaboration with Laboratorio de Estudios Cristalográficos, Granada, Spain is to crystallize higher plant PS II for high resolution X-ray diffraction and resolve the structure of the supercomplex.

I will employ a combination of (sucrose density) centrifugation and chromatography (ion exchange, gel filtration) techniques for extraction and purification of the PSII complexes from solubilised thylakoid membranes of the Pisum sativum L. chloroplasts. I will follow the complexes’ activity throughout the isolation routine with optical spectroscopy and polarographic measurements of oxygen evolution rates. I will use the present-day and adopt upcoming methods and approaches for crystallisation of both membrane and soluble proteins.

I have already established a protocol for hydroponic plant growth under controlled conditions. I am now re-designing and implementing a novel protocol for isolation of the PS II enriched thylakoid membranes. I will carry out screening for most suitable buffers and detergents that will sustain maximum PSII activity throughout the isolation routine. Later, I will join the Spanish group in their task to develop the protocol for PSII purification. I will then begin the crystallization of the PSII complexes.