ISSN:
1432-072X
Keywords:
Photosynthetic membranes
;
Electron microscopy
;
Image processing
;
Ectothiorhodospira halochloris
;
Ectothiorhodospira abdelmalekii
;
Rhodopseudomonas viridis
;
Rhodopseudomonas sulfoviridis
;
Thiocapsa pfennigii
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The photosynthetic membranes of the five bchl b-containing bacteria Ectothiorhodospira halochloris, E. abdelmalekii, Rhodopseudomonas viridis, R. sulfoviridis and Thiocapsa pfennigii have been investigated by electron microscopy and digital image analysis. All five species have the photosynthetic complexes hexagonally arrayed in the membrane with lattice spacings close to 13 nm, except for R. sulfoviridis and T. pfennigii which display somewhat smaller (∼12.5 nm) lattice spacings. Correlation averaging which imposes less stringent requirements on the lattice perfection than conventional Fourier filtration techniques has been employed to elucidate the structure of the photosynthetic complexes. Their basic organization, i.e. a ring, probably containing the light-harvesting (LH) polypeptides, surrounding a core (the “reaction centre”) appears to be almost identical for all species under scrutiny. Despite a resolution of ∼1.6 nm, however, little further significant substructure can be deduced from the averages; possible reasons for the “blurred” appearance of the LH-ring and absence of any subdivision in the reaction centre are discussed along with strategies aimed at obtaining a more detailed model of the molecular architecture of the photosynthetic membranes.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00414474
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