Structure and orientation of the Mn4Ca cluster in plant photosystem II membranes studied by polarized range-extended x-ray absorption spectroscopy. Export

@article{Pushkar2007, abstract = {X-ray absorption spectroscopy has provided important insights into the structure and function of the Mn(4)Ca cluster in the oxygen-evolving complex of Photosystem II (PS II). The range of manganese extended x-ray absorption fine structure data collected from PS II until now has been, however, limited by the presence of iron in PS II. Using a crystal spectrometer with high energy resolution to detect solely the manganese Kalpha fluorescence, we are able to extend the extended x-ray absorption fine structure range beyond the onset of the iron absorption edge. This results in improvement in resolution of the manganese-backscatterer distances in PS II from 0.14 to 0.09A(.) The high resolution data obtained from oriented spinach PS II membranes in the S(1) state show that there are three di-mu-oxo-bridged manganese-manganese distances of approximately 2.7 and approximately 2.8A in a 2:1 ratio and that these three manganese-manganese vectors are aligned at an average orientation of approximately 60 degrees relative to the membrane normal. Furthermore, we are able to observe the separation of the Fourier peaks corresponding to the approximately 3.2A manganese-manganese and the approximately 3.4A manganese-calcium interactions in oriented PS II samples and determine their orientation relative to the membrane normal. The average of the manganese-calcium vectors at approximately 3.4A is aligned along the membrane normal, while the approximately 3.2A manganese-manganese vector is oriented near the membrane plane. A comparison of this structural information with the proposed Mn(4)Ca cluster models based on spectroscopic and diffraction data provides input for refining and selecting among these models.}, address = {Melvin Calvin Laboratory, Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-5230, USA.}, author = {Pushkar, Y. and Yano, J. and Glatzel, P. and Messinger, J. and Lewis, A. and Sauer, K. and Bergmann, U. and Yachandra, V.}, citeulike-article-id = {1550259}, citeulike-linkout-0 = {http://dx.doi.org/10.1074/jbc.M610505200}, citeulike-linkout-1 = {http://view.ncbi.nlm.nih.gov/pubmed/17190828}, citeulike-linkout-2 = {http://www.hubmed.org/display.cgi?uids=17190828}, day = {9}, doi = {10.1074/jbc.M610505200}, issn = {0021-9258}, journal = {J Biol Chem}, keywords = {exafs, mn, oec, psii, psii\_exafs}, month = {March}, number = {10}, pages = {7198--7208}, posted-at = {2007-08-09 16:40:04}, priority = {2}, title = {Structure and orientation of the Mn4Ca cluster in plant photosystem II membranes studied by polarized range-extended x-ray absorption spectroscopy.}, url = {http://dx.doi.org/10.1074/jbc.M610505200}, volume = {282}, year = {2007} }

TY - JOUR ID - Pushkar2007 L3 - citeulike-article-id:1550259 N2 - X-ray absorption spectroscopy has provided important insights into the structure and function of the Mn(4)Ca cluster in the oxygen-evolving complex of Photosystem II (PS II). The range of manganese extended x-ray absorption fine structure data collected from PS II until now has been, however, limited by the presence of iron in PS II. Using a crystal spectrometer with high energy resolution to detect solely the manganese Kalpha fluorescence, we are able to extend the extended x-ray absorption fine structure range beyond the onset of the iron absorption edge. This results in improvement in resolution of the manganese-backscatterer distances in PS II from 0.14 to 0.09A(.) The high resolution data obtained from oriented spinach PS II membranes in the S(1) state show that there are three di-mu-oxo-bridged manganese-manganese distances of approximately 2.7 and approximately 2.8A in a 2:1 ratio and that these three manganese-manganese vectors are aligned at an average orientation of approximately 60 degrees relative to the membrane normal. Furthermore, we are able to observe the separation of the Fourier peaks corresponding to the approximately 3.2A manganese-manganese and the approximately 3.4A manganese-calcium interactions in oriented PS II samples and determine their orientation relative to the membrane normal. The average of the manganese-calcium vectors at approximately 3.4A is aligned along the membrane normal, while the approximately 3.2A manganese-manganese vector is oriented near the membrane plane. A comparison of this structural information with the proposed Mn(4)Ca cluster models based on spectroscopic and diffraction data provides input for refining and selecting among these models. IS - 10 JF - J Biol Chem SN - 0021-9258 AD - Melvin Calvin Laboratory, Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-5230, USA. EP - 7208 TI - Structure and orientation of the Mn4Ca cluster in plant photosystem II membranes studied by polarized range-extended x-ray absorption spectroscopy. VL - 282 SP - 7198 KW - exafs KW - mn KW - oec KW - psii KW - psii_exafs AU - Pushkar, Y AU - Yano, J AU - Glatzel, P AU - Messinger, J AU - Lewis, A AU - Sauer, K AU - Bergmann, U AU - Yachandra, V PY - 2007/03/09/ UR - http://dx.doi.org/10.1074/jbc.M610505200 ER -