ISSN:
1600-5767
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Geosciences
,
Physics
Notes:
The structures of kinetically distinct electron transfer complexes formed between the photosynthetic reaction center from Rhodobacter sphaeroides R-26, and a water-soluble cytochrome c2 were characterized using small angle neutron scattering, SANS. Reaction center-cytochrome c2 complexes, RC-C, exhibiting predominately single exponential electron transfer kinetics were found to be 1:1 molar complexes, consistent with a low resolution, co-crystal, x-ray structure (Adir et al., 1996), provided that the cofactor separation was adjusted to 14 ± 3 Å. Other RC-C configurations are consistent with SANS data, but are distinguishable by cofactor separation. RC-C preparations exhibiting more complex kinetics were found to have a particle volume markedly greater than that of a 1:1 complex. These results suggest that RC aggregation is associated with the variation in kinetics reported in the literature, and provide evidence that the model for the 1:1 complex in co-crystals is relevant to the solution environment.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0021889800099891
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