FIGURE 2.
X-ray Guinier Rg and Rxs analyses for four MBL oligomers. In the Guinier analyses, the open circles correspond to the data points, and the filled circles and lines correspond to the data points used to determine the Rg and Rxs values. The Q·Rg and Q·Rxs values for the fit ranges are denoted by arrows. The data are for concentrations of 0.31 and 0.46 mg/ml for monomeric MBL, 0.56 and 0.86 mg/ml for dimeric MBL, 0.46 and 0.69 mg/ml for trimeric MBL, and 0.43 and 0.70 mg/ml for tetrameric MBL. In all panels, the upper and lower plots correspond to the upper and lower concentrations respectively. For reason of clarity, the Guinier plots are displaced by 1.5 units on their vertical axes. A–D, Guinier plots of ln I(Q) versus Q2 to obtain the Rg values for MBL. The Q fit ranges were 0.10–0.17, 0.08–0.14, 0.08–0.15, and 0.06–0.10 nm−1 for the monomer (A), dimer (B), trimer (C), and tetramer (D), respectively. E–H, Guinier plots of ln I(Q)·Q versus Q2 to obtain the Rxs−1 values for MBL. The Q fit ranges were 0.41–0.65 nm−1 for the monomer (E), 0.42–0.58 nm−1 for the dimer (F) and trimer (G), and 0.41–0.56 nm−1 for the tetramer (H). I–L, Guinier plots to obtain the Rxs−2 values for MBL. The Q fit ranges were 0.65–0.92 nm−1 for the monomer (I), 0.65–0.85 nm−1 for the dimer (J) and trimer (K), and 0.68–0.85 nm−1 for the tetramer (L).