Thumbnail Image

Crystallization of Intact and Subunit L-Deficient Monomers from Synechocystis PCC 6803 Photosystem I

Jekow, Petra; Schubert, Wolf-Dieter; Fromme, Petra; Kruip, Jochen; Chitnis, Parag R.; Rögner, Matthias; Saenger, Wolfram

Inst. Chemie

Photosystem I monomers from wildtype cells of Synechocystis PCC 6803 and from a mu­tant deficient in the psaL gene were crystallized. PsaL encodes for the hydrophobic subunit L, which has been proposed to constitute the trimerization domain in the PS I trimer. The absence of subunit L facilitated crystallization of the PS I monomer. The unit cell dimensions and the space group for the crystals from this preparation could be determined to be a = b = 132 Å , c -525 Å, α = β = 90°, y = 120°, the space group is P61 or P65. The results show the potential of using specifically designed deletion mutants of an integral membrane protein for the systematic improvement of crystal structure data.