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RC-LH1 core complex from R. palustris Neil Isaacs Department of Chemistry University of Glasgow.

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Presentation on theme: "RC-LH1 core complex from R. palustris Neil Isaacs Department of Chemistry University of Glasgow."— Presentation transcript:

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2 RC-LH1 core complex from R. palustris Neil Isaacs Department of Chemistry University of Glasgow

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4 ATP synthase ATPADP + P i H+H+ H+H+ H+H+ H+H+ LH2LH1 RC Light Cyt c Q Q Q QQ Q e-e- e-e- e-e- B800 B850 B880 Cytochrome b/c 1 Cytoplasm Periplasm QBQB Q Photosynthetic system of purple bacteria

5 Peripheral light-harvesting antenna (LH2 complex) from Rh. Acidophila, McDermott et al. (1995) Nature 374, 517.

6 Shown above is the structure of RC from Rhodobacter sphaeroides, Allen, et al. (1987) PNAS, 84, 5730; McAuley, et al. (1999) PNAS, 96, 14706. First structure of reaction centre, from Rhodopseudomonas viridis, was determined by Deisenhofer, et al. (1985) Nature 318, 618. The Bacterial Reaction Centre

7 Cytochrome bc1(Iwata et al (1998) Science, 281, 64—71)

8 F1ATPase Abrahams et al, (1994) Nature, 370, 621--8

9 ATP synthase ATPADP + P i H+H+ H+H+ H+H+ H+H+ LH2LH1 RC Light Cyt c Q Q Q QQ Q e-e- e-e- e-e- B800 B850 B880 Cytochrome b/c 1 Cytoplasm Periplasm QBQB Q

10 Karrasch et al. (1995) EMBO J., 14, 631. Electron Microscopy 8.5 Å projection map for 2D-crystal of the reconstituted light-harvesting complex I (LH1) from Rhodospirillum rubrum.

11 Hypothetical model of the purple bacteria PSU Papiz MZ, Prince SM, Hawthornthwaite-Lawles AM, McDermott G, Freer AA, Isaacs NW & Cogdell RJ (1996) Trends Plant Sci. 1, 198-206. LH1 RC LH2

12 Walz, et al. (1998) J. Mol. Biol. 282, 833. Electron Microscopy 25 Å projections for 2D-crystals of the RC-LH1 complex from Rhodobacter sphaeroides.

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15 Diffraction from crystals of the LH1-RC core complex

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17 Current electron density map

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19 QBQB W

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21 S. Bahatyrova et al, (2004) Nature, 430, 1058-1062 AFM shows the arrangement of photosynthetic complexes in the membrane

22 Questions to tax the brain: What is protein W? How does LH1 interact with RC? How does W interact with RC and LH1? How does the complex assemble? 34 proteins 2 Ubiquinone 19 Bchl 16? Carotenoid 2 Pheophytin Fe > 70 components & no instructions….

23 Separation of organic solvent soluble polypeptides

24 LH1-RC core   6.5 14 21  -dimers  -polypeptide  -polypeptide 10 15 20 W? 6.5 14 21 SDS-PAGE of purified low-molecular weight LH polypeptides

25 The crystal structure of the RC LH1 core complex from Rhodopseudomonas palustris Aleksander W. Roszak, Tina D. Howard, June Southall, Alastair T. Gardiner, Neil W. Isaacs and Richard J. Cogdell BBSRC Wellcome Trust SRS Daresbury, stations14.1 and 9.6

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27 Questions: What is protein W? How does LH1 interact with RC? How does W interact with RC and LH1? How does the complex assemble? 34 proteins 2 Ubiquinone 19 Bchl 16? Carotenoid 2 Pheophytin Fe > 70 components & no instructions….

28 Cytochrome bc 1 (Iwata et al (1998) Science, 281, 64—71)

29 F1ATPase Abrahams et al, (1994) Nature, 370, 621--8


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