Comparative analysis of the composition of two chlorophyll-b-containing light-harvesting complexes

Wilhelm, Christian; Wiedemann, I.; May, Mike

doi:10.1007/bf01160404

Cited by 2 publications

(1 citation statement)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Native or reconstituted LHC in 400 #10.05 M TRIS/borate (pH 8.2) were precipitated by 2.4 ml cold (4°C) acetone on ice for 15 min to ensure complete precipitation and centrifuged by 5500 g, 15 min, 4°C. The suitability of the method was proven by comparing the pigment-protein stoichiometries of the LHC of C. fusca (Chl/PP = 13.95 + 1.23, n = 6) with data published by Wilhelm et al 1990 (Chl/PP = 15 -4-5.1, n = 40 obtained by Coomassie blue protein staining on SDS-PAGE). Defined amounts of quantified native and reconstituted LHC were used for HPLC-analysis as described by Meyer and Wilhelm (1993).…”

Section: Methodsmentioning

confidence: 99%

Pigment-pigment interactions and secondary structure of reconstituted algal chlorophyll a/b-binding light-harvesting complexes of Chlorella fusca with different pigment compositions and pigment-protein stoichiometries

Meyer¹,

Wilhelm

Garab

1996

Photosynth Res

View full text Add to dashboard Cite

Earlier we have shown by in vitro reconstitution experiments that the pigment composition of the chlorophyll alb-binding light-harvesting complex of the green alga Chlorella fusca could be altered in a relatively broad range (Meyer and Wilhelm 1993). In this study we used these reconstituted complexes of different pigment loading to analyze the excitonic interactions between the pigment molecules and the secondary structure by means of circular dichroism spectra in the visible and the far UV spectral regions, respectively. We found that, in contrast to the expectations, the pigment composition and pigment content hardly affected the circular dichroism spectra in the visible spectral region. Reconstituted complexes, independent of their pigment composition, exhibited the most characteristic circular dichroism bands of the native light-harvesting complex, even if one polypeptide bound only 3 chlorophyll a, 3 chlorophyll b and 1-2 xanthophyll molecules. Full restoration of the protein secondary structure, however, could not be achieved. The α-helix content depended significantly on the pigment composition as well as on the pigment-protein ratio of the reconstituted complexes. Further binding of pigments resulted in restoration of the minor excitonic circular dichroism bands, the amplitudes of which depended on the pigment content of the reconstituted complexes. These data suggest that in the reconstitution of light-harvesting complexes a 'central cluster' of pigment molecules plays an important role. Further binding of pigments to the 'peripheral binding sites' appeared also to stabilize the protein secondary structure of the reconstituted complexes.

show abstract

Section: Methodsmentioning

confidence: 99%