Figure 4
Synchrotron small-angle X-ray scattering data and analysis of LPN with C18 mPEG 2000 lipids. (a) Radially averaged scattering intensities of MTs and MT–lipid complexes (solid symbols), using DOTAP/(DOPC + C18mPEG2000) solutions with xCL = NCL/(NCL + NNL) = 0.5, with increasing C18mPEG 2000 percentage, as indicated in the figure. RCL/T = NCL/NT = 80. The broken curve is an example of the assumed background (Andreu et al., 1992; Fernando-Diaz et al., 1996; Needleman et al., 2004b). (b) Scattering data from (a), following background subtraction (open symbols). The solid curves are the fitted scattering models. Their χ2 values are as in the figure. (c) The variation of the radial electron density, Δρ(r), relative to water (broken lines), of the MTs and complex walls, obtained from fitting the scattering data in (b) to models of concentric cylinders. r is the distance from the center of the cylinders. The values for the tubulin oligomer coverage, f, obtained from the nonlinear fit are indicated on the right side. |