Cyanobacterial Photosystem II at 3.2 A resolution - the plastoquinone binding pockets.

@article{citeulike:297525, abstract = {Photosystem II from thylakoid membranes of the thermophilic cyanobacterium Thermosynechococcus elongatus was solubilized with n-beta-dodecylmaltoside and purified using anion exchange chromatography. Molecular weight, pigment stoichiometry and subunit composition were assayed using various techniques. The holocomplex is dimeric with a molecular mass of 756 +/- 18 kDa and functionally fully active. Crystals obtained from these samples showed significantly improved quality leading to a 3D structure at 3.2 A resolution. Several loop regions of the principal protein subunits are now defined that were not interpretable at lower (3.8 A) resolution, thus resulting in a more complete model. The head groups of the cofactors of the electron transfer chain and of the antennae have been modeled, coordinating and hydrogen bonding amino acids identified and the nature of the binding pockets derived. The orientations of these cofactors resemble those of the reaction centre from anoxygenic purple bacteria. For the two plastoquinones, electron density was only found for the head group of Q(A) and none for Q(B) indicating low or even no occupancy of this site in the crystal structure. Both binding pockets and problems related to the Q(B) site are discussed here and compared to the situation in the purple bacterial reaction centre.}, address = {Max-Volmer-Laboratories for Biophysical Chemistry, Technical University Berlin, Strasse des 17 Juni 135, 10623, Berlin, Germany, irrg0532@mailbox.tu-berlin.de.}, author = {Kern, J. and Loll, B. and Zouni, A. and Saenger, W. and Irrgang, K. D. and Biesiadka, J. }, citeulike-article-id = {297525}, doi = {http://dx.doi.org/10.1007/s11120-004-7077-x}, issn = {0166-8595}, journal = {Photosynth Res}, keywords = {psii, psii\_biochemistry, psii\_structure, psii\_xtal}, number = {1-3}, pages = {153--159}, posted-at = {2005-08-18 15:24:27}, priority = {2}, title = {Cyanobacterial Photosystem II at 3.2 A resolution - the plastoquinone binding pockets.}, url = {http://dx.doi.org/10.1007/s11120-004-7077-x}, volume = {84}, year = {2005} }

TY - JOUR ID - citeulike:297525 L3 - citeulike-article-id:297525 TI - Cyanobacterial Photosystem II at 3.2 A resolution - the plastoquinone binding pockets. JF - Photosynth Res VL - 84 IS - 1-3 SP - 153 EP - 159 AD - Max-Volmer-Laboratories for Biophysical Chemistry, Technical University Berlin, Strasse des 17 Juni 135, 10623, Berlin, Germany, irrg0532@mailbox.tu-berlin.de. SN - 0166-8595 N2 - Photosystem II from thylakoid membranes of the thermophilic cyanobacterium Thermosynechococcus elongatus was solubilized with n-beta-dodecylmaltoside and purified using anion exchange chromatography. Molecular weight, pigment stoichiometry and subunit composition were assayed using various techniques. The holocomplex is dimeric with a molecular mass of 756 +/- 18 kDa and functionally fully active. Crystals obtained from these samples showed significantly improved quality leading to a 3D structure at 3.2 A resolution. Several loop regions of the principal protein subunits are now defined that were not interpretable at lower (3.8 A) resolution, thus resulting in a more complete model. The head groups of the cofactors of the electron transfer chain and of the antennae have been modeled, coordinating and hydrogen bonding amino acids identified and the nature of the binding pockets derived. The orientations of these cofactors resemble those of the reaction centre from anoxygenic purple bacteria. For the two plastoquinones, electron density was only found for the head group of Q(A) and none for Q(B) indicating low or even no occupancy of this site in the crystal structure. Both binding pockets and problems related to the Q(B) site are discussed here and compared to the situation in the purple bacterial reaction centre. KW - psii KW - psii_biochemistry KW - psii_structure KW - psii_xtal AU - Kern, J AU - Loll, B AU - Zouni, A AU - Saenger, W AU - Irrgang, KD AU - Biesiadka, J PY - 2005/// UR - http://dx.doi.org/10.1007/s11120-004-7077-x ER -