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

Jan 02, 2016

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RC-LH1 core complex from R. palustris. Neil Isaacs Department of Chemistry University of Glasgow. Periplasm. Light. Cytochrome b/c 1. H +. LH2. LH1. e -. e -. H +. Cyt c. Q. Q. B850. B880. e -. Q. RC. Q. Q. Q. B800. Q B. Q. ADP + P i. ATP. H +. H +. Cytoplasm. - PowerPoint PPT Presentation
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Page 1: RC-LH1 core complex from  R. palustris

RC-LH1 core complex from R. palustrisNeil Isaacs

Department of Chemistry

University of Glasgow

Page 2: RC-LH1 core complex from  R. palustris
Page 3: RC-LH1 core complex from  R. palustris

ATP synthase

ATPADP + Pi

H+

H+

H+

H+

LH2 LH1

RC

Light

Cyt c

Q

Q

Q

Q Q

Qe-

e-e-

B800

B850 B880

Cytochrome b/c1

Cytoplasm

Periplasm

QB

Q

Photosynthetic system of purple bacteria

Page 4: RC-LH1 core complex from  R. palustris

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

Page 5: RC-LH1 core complex from  R. palustris

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

Page 6: RC-LH1 core complex from  R. palustris

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

Page 7: RC-LH1 core complex from  R. palustris

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

Page 8: RC-LH1 core complex from  R. palustris

ATP synthase

ATPADP + Pi

H+

H+

H+

H+

LH2 LH1

RC

Light

Cyt c

Q

Q

Q

Q Q

Qe-

e-e-

B800

B850 B880

Cytochrome b/c1

Cytoplasm

Periplasm

QB

Q

Page 9: RC-LH1 core complex from  R. palustris

Karrasch et al. (1995) EMBO J., 14, 631.

Electron Microscopy 8.5 Å projection map for 2D-crystalof the reconstituted light-harvesting complex I (LH1) fromRhodospirillum rubrum.

Page 10: RC-LH1 core complex from  R. palustris

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

Page 11: RC-LH1 core complex from  R. palustris

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.

Page 12: RC-LH1 core complex from  R. palustris
Page 13: RC-LH1 core complex from  R. palustris
Page 14: RC-LH1 core complex from  R. palustris

Diffraction from crystals of the LH1-RC core complex

Page 15: RC-LH1 core complex from  R. palustris
Page 16: RC-LH1 core complex from  R. palustris

Current electron density map

Page 17: RC-LH1 core complex from  R. palustris
Page 18: RC-LH1 core complex from  R. palustris

QB

W

Page 19: RC-LH1 core complex from  R. palustris
Page 20: RC-LH1 core complex from  R. palustris

S. Bahatyrova et al, (2004) Nature, 430, 1058-1062

AFM shows the arrangement of photosynthetic complexes in the membrane

Page 21: RC-LH1 core complex from  R. palustris

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….

Page 22: RC-LH1 core complex from  R. palustris

LH60 column of Rps. palustris 'French' core complex

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 20 40 60 80 100 120

Fraction Number

Ab

sorb

an

ce (

280n

m)

RC polypeptides

LH polypeptidesPigments/phospholipids

W?

Separation of organic solvent soluble polypeptides

Page 23: RC-LH1 core complex from  R. palustris

LH1-RC core

6.5

14

21 -dimers

-polypeptide

-polypeptide10

15

20

W?

6.5

14

21

SDS-PAGE of purified low-molecular weight LH polypeptides

Page 24: RC-LH1 core complex from  R. palustris

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

Page 25: RC-LH1 core complex from  R. palustris
Page 26: RC-LH1 core complex from  R. palustris

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….

Page 27: RC-LH1 core complex from  R. palustris

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

Page 28: RC-LH1 core complex from  R. palustris

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