CHARACTERIZATION OF 3-DIMENSIONAL CRYSTALS OF PHOTOSYSTEM II FROM SYNECHOCOCCUS ELONGATUS
1Zouni A., 1Fromme P., 2Schubert W.D., 2Saenger W., 1Witt H.T.
1Max-Volmer-Institut, Technische Universität Berlin, Str. d. 17. Juni 135, D-10623 Berlin
2Institut für Kristallographie, Freie Universtität Berlin, Takustr. 6, D-14195 Berlin
Keywords: photosystem 2, single crystals
Highly purified photosystem II complexes were isolated from Synechococcus elongatus. The PS II core complex includes the water-oxidizing center. Crystallization of this protein was performed at 20oC in the presence of polyethylene glycol and CaCl2. Single crystals with sizes of 30-400 µm were obtained within 1-2 days. The crystals belong to the orthorhombic space group P222121 or P22212. The unit cell constants are a=134 Å, b=227 Å and c=310 Å. The cell contains four PS II core complexes. Using synchrotron radiation, the crystals diffract X-rays to a resolution of 6 Å at cryogenic temperature. A native data set has been collected.