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Last modified: 15 August 1997

Light­harvesting complex II (Rhodospirillum molischianum) structure [1]

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a = 324 K; b = 57 K; c = 78 K; d = 275 K; e = 30 K.

PDB scop BSM RELI
Base		 Header MMS Abstract ¹
1lgh 1lgh 1lgh 1lgh Light­harvesting complex II (B800­850); Rhodospirillum molischianum MS7RRC1
1LGH image
a		 1LGH cofactors image
b
1LGH octamer image c
c		 1LGH octamer image d
d
1LGH BChl ligation image
e

¹ Macromolecular Structures abstract. Full text is available to BioMedNet Members

  1. Ribbon representation of the light­harvesting complex II (LH­II) proteins from Rhodospirillum molischianum (PDB code 1LGH). The biologically active LH­II is an octamer of alphaß heterodimers. In 1LGH, the asymmetric unit consists of four alphaß dimers (AB, DE, GH and JK). The dimers AB and DE belong to one octamer and the dimers GH and JK belong to another octamer. Each dimer binds three bacteriochlorophyll a (BChl­a) molecules and one carotenoid molecule (not shown). Two BChl­a molecules with absorption maximum at 846 nm (B850) are perpendicular to the membrane plane and sandwiched between alpha and ß subunits; one of these molecules is bound to the alpha subunit (B850alpha) and the other is bound to the ß subunit (B850ß). One BChl­a molecule with absorption maximum at 800 nm (B800) is bound to the alpha subunit and is tilted away from the membrane plane by 38° [1]. Subunit colour­codes: chain A (alpha) = dark red; chain B (ß) = dark violet; chain D (alpha) = orange; chain E (ß) = dark blue; chain G (alpha) = light blue; chain H (ß) = dark green; chain J (alpha) = dark cyan; chain K (ß) = light green.
  2. The arrangement of prosthetic groups of LH­II (orientation as a). Colour­codes: B850alpha = deep red; B850ß = deep purple; B800 = dark green; carotenoid (lycopene) = brown. The phytyl chains of BChl­a are not shown.
  3. Arrangement of prosthetic groups in the LH­II octameric complex (top view). This image was generated using the coordinates for chains G, H, J and K from 1LGH by applying rotational transformations (0°, 90°, 180°, 270°). Colour­codes as b.
  4. As c, carotenoids are not shown; the transmembrane helices of alpha and ß subunits are shown (alpha subunits form the inner circle and ß subunits form the outer one).
  5. The axial ligation of BChl­a in GH and JK dimers. Orientation and colour­codes of BChl­a as b.
All drawings were produced by using the program MOLSCRIPT [2].

References

  1. Koepke, J., Hu, X., Muenke, C., Schulten, K. and Michel, H. (1996) The crystal structure of the light­harvesting complex II (B800­850) from Rhodospirillum molischianum. Structure 4, 581-597.
  2. Kraulis, P.J. (1991) MOLSCRIPT: a program to produce both detailed and schematic plots of protein structure. J. Appl. Crystallogr. 24, 946-950.
Bibliography on structural studies of light­harvesting complex II of purple bacteria