 | Acta Crystallographica Section D Acta Crystallographica Section D BIOLOGICAL CRYSTALLOGRAPHY |
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![[Figure 1]](bw5288fig1mag.jpg)
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Figure 1
Characterization of protein and lipid impurities found within partially purified RC samples used for crystallization experiments. Protein analyses (a, c) are depicted as digitized intensities from Coomassie-stained SDS–PAGE gels. Lipid analyses (b, d) comprise iodine-stained TLC plates. For the partially purified samples (a) and (b), the RC content was kept constant using 12 and 30 µg in each gel and TLC lane, respectively. The numbers above the lanes indicate the A280/A800 ratio of the sample. Assignments of spots on the TLC plate in (b) signify the detergent and lipid components present in the samples that are resolved by this solvent system: Pigments, a mixture comprised of bacteriochlorophylls, bacteriopheophytins, carotenoids and quinones; LDAO, N,N-dimethyldodecylamine-N-oxide; MGDG, monogalactosyldiacylglycerol; CL, cardiolipin; PE, phosphatidylethanolamine; PC, phosphatidylcholine; PG, phosphatidylglycerol. Increases in LDAO intensities observed on the TLC plate in (b) can be attributed to an overall increase in total protein in samples with decreasing purity (increasing levels of impurities), resulting in a higher overall level of PDCs (daCosta & Baenziger, 2003  ). For samples with lipids or membranes added (c, d), the exact contents of the LCP-based trials (0.5 mg of each) in the absence of MO were loaded for analysis. The samples contained (1) RCs only, (2) RCs plus 12% polar brain lipids, (3) RCs plus 18% polar E. coli lipids, (4) RCs plus 1.2% extracted R. sphaeroides lipids, (5) RCs plus 12% R. sphaeroides whole membranes. For both sets of samples, bands corresponding to the three protein subunits (L, M and H; ∼25–30 kDa) of the R. sphaeroides RC complex are marked with a bracket and the lanes containing molecular-weight standards [ProSieve Protein Markers from Lonza in (a) and Full-Range Rainbow Marker from GE Healthcare in (c)] are indicated (lane L). |
![[Figure 1]](bw5288fig1.jpg)
| BIOLOGICAL CRYSTALLOGRAPHY |
ISSN: 1399-0047
