Johann Deisenhofer 博士 講演会

講師：Prof. Dr. Johann Deisenhofer (University of Texas Southwestern Medical Center, Dallas, USA)
演題：Structural Biology of Photosynthetic Light Reactions
日時：2013年10月17日 (木) 16:30〜18:00
会場：京都大学大学院理学研究科セミナーハウス，大セミナー室

ダイゼンホーファー博士は，光合成反応中心複合体のX線結晶解析の成功によって，1988年のノーベル化学賞を受賞した構造生物学者・タンパク質結晶学者です．今回の来日は，日本学術振興会の外国人著名研究者招へい事業（受入機関：京都大学）によるものです．なお，この講演は10月13日に日本結晶学会平成25年度年会（熊本大学）での特別講演を，本学でも行っていただくものです．

ABSTRACT: In this lecture I will give an overview of crystal structures of photosynthetic reaction centers (RCs) and photosystems (PS I and PS II), with emphasis on common features. The structure of the RC from the purple bacterium Rhodopseudomonas viridis (now Blastochloris viridis), a complex of 4 protein subunits and 14 co-factors, showed in its core an arrangement of chlorophylls, pheophytins and quinones with an approximate twofold symmetry (Deisenhofer et al. 1985). This structural symmetry is in contrast to functional asymmetry, with electron transfer preferentially along only one of two paths formed by chlorophylls, a pheophytin, a quinone, ending on the second quinone. A similar twofold structural symmetry exists in the cores of PS I (Jordan et al. 2001) and PS II (Zouni et al. 2001; Umena et al. 2011). While the functional asymmetry is almost complete in PS II, it is less so in PS I (Poluektov et al. 2005). The structural similarity of the cores of RC, PS I, and PS II strongly supports the assumption of a common evolutionary origin of these complexes.

• Deisenhofer, J, O Epp, K Miki, R Huber, and H Michel. 1985. Structure of the protein subunits in the photosynthetic reaction centre of rhodopseudomonas viridis at 3A resolution. Nature 318 (6047): 618-24.
• Jordan, P, P Fromme, H T Witt, O Klukas, W Saenger, and N Krauss. 2001. Threedimensional structure of cyanobacterial photosystem I at 2.5 A resolution. Nature 411 (6840): 909-17.
• Poluektov, Oleg G, Sergei V Paschenko, Lisa M Utschig, K V Lakshmi, and Marion C Thurnauer. 2005. Bidirectional electron transfer in photosystem I: Direct evidence from high-frequency time-resolved EPR spectroscopy. J Am Chem Soc 127 (34): 11910-1.
• Umena, Yasufumi, Keisuke Kawakami, Jian-Ren Shen, and Nobuo Kamiya. 2011. Crystal structure of oxygen-evolving photosystem II at a resolution of 1.9 A. Nature 473 (7345): 55-60.
• Zouni, A, H T Witt, J Kern, P Fromme, N Krauss, W Saenger, and P Orth. 2001. Crystal structure of photosystem II from synechococcus elongatus at 3.8 A resolution. Nature 409 (6821): 739-43.