A series of light-harvesting 1 ( @entity24030 ) complexes was isolated by @entity31092 - @entity2975 gel electrophoresis at 4 degrees C from @entity11704 M21, which lacks the peripheral light-harvesting 2 (LH2) complex. This ladder of @entity24030 bands was also demonstrated in the wild type, partially superimposed upon a smaller number of LH2 complexes. An assessment of electrophoretic mobility vs @entity3323 concentration, in which the reaction center LM particle and annular @entity24030 and LH2 complexes were used as standards of known structure, indicated that the @entity24030 gel bands 2 to 10 represent regular oligomers of an alpha beta heterodimeric unit, that vary in size from (alpha beta)(2-3) to (alpha beta)(10-11). The isolated @entity24030 complexes exhibited oligomeric state dependent optical properties, characterized by red shifts in near-IR absorption and emission maxima at 77 K of approximately 6 nm as aggregate sizes increased from approximately 3 to 7-8 alpha beta-heterodimers, accompanied by shifts in highly polarized fluorescence from the blue to the red side of the absorption band. This has been explained by the oligomerization of heterodimers to form a curvilinear array of excitonically coupled chromophores, with the anisotropic long-wavelength component, designated originally as B896, corresponding to low energy excitonic transitions arising from interactions within inhomogeneous BChl clusters [Westerhuis et al. (1999) J. Phys. Chem. B 103, 7733-7742]. Differences in electrophoretic profiles of @entity24030 bands between strains M21 and M2192, an @entity24030 -only strain that also lacks PufX, further suggested that the more rapidly migrating bands represent arced fragments of the curvilinear array of @entity24030 complexes thought to exist as a large closed circular structure only in the latter strain. The electrophoretic banding pattern also indicated that the @entity24030 complex may be located at the peripheries of dimeric intramembrane particle arrays seen in freeze- @entity174 replicas of tubular M21 membranes; the possible role for the PufX protein in the assembly of these structures is discussed.

Isolation, size estimates, and spectral heterogeneity of an oligomeric series of light-harvesting 1 complexes from XXXX .

@entity174 :: ('MESH:D050723', 'Disease') :: ['fracture'] @entity11704 :: ('1063', 'Species') :: ['Rhodobacter sphaeroides'] @entity31092 :: ('MESH:C028913', 'Chemical') :: ['lithium dodecyl sulfate'] @entity3323 :: ('MESH:D020106', 'Chemical') :: ['acrylamide'] @entity2975 :: ('CHEBI:51135', 'Chemical') :: ['polyacrylamide'] @entity24030 :: ('MESH:C009955', 'Chemical') :: ['LH1']
@entity11704 :: (1063,Species) :: ['Rhodobacter sphaeroides']
