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Biological specimen preparation; Biomembranes; Statistical analysis; Natural and artificial biomembranes [A8720E]; Physics of subcellular structures [A8725F]; Biophysical instrumentation and techniques [A8780]
Abstract:
The surface reliefs of photosynthetic membranes from the bacterium Ectothiorhodospira halochloris have been reconstructed from shadowing data. Freeze-dried membranes were shadowed unidirectionally with tantalum/tungsten at low specimen temperature ( approximately 20K). The membranes, which contain the photosynthetic complexes hexagonally packed, show two distinctly different faces. Analysis of the apparent molecular displacement on the two faces suggests that not all features are compatible with P6 symmetry but may vary from one unit cell to another. Correspondence analysis and differential averaging created subsets reflecting the nature of the variability, namely an asymmetry and rotational variability of the reaction centre complex with respect to the surrounding ring of light-harvesting complexes. (16 References).