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Figure 2
Colour-coded spatial distribution of conformations of a two-ellipsoid system illustrating the effect of progressive activation of SAS and NMR restraints. θ/φ designate the polar/azimuthal angles of the 40/30/20 Å (green) ellipsoid with respect to the common centre of mass [see (e)]. Warm colours (red, orange…) indicate good fits and cold colours (blue, violet) indicate poor fits against the reference SAXS curve calculated from the target model shown in (e). (a) Spatial distribution of the centre of the small (green) ellipsoid as a function of the polar angles (θ/φ) using arbitrary orientations of both ellipsoids and an inter-ellipsoid distance that varies between the target distance (70 Å) ±30%. (b) As in (a) but both ellipsoids are orientated as in the target structure. (c) Cross-section of (a) at the target distance (70 Å). (d) Cross-section of (b) at the target distance (70 Å). (e) Target model (θ/φ = 0.5π/π) and reference χ2 fit against its noise-endowed SAXS data. (f) Spatial distribution of 23 alternative structures (out of 2000 calculated) that are in excellent agreement (χ2 < 1.5) with the SAXS data of the target structure (transparent green). (The 50/20/10 Å cyan ellipsoid has been superposed for all structures.) The 23 structures are represented by red spheres indicating their centres of mass. Several of them correspond to symmetric solutions (transparent red spheres) which are located in a plane behind the cyan partner [red zone on the left-hand side of (d)]. For reasons of clarity, only two alternative models are depicted fully in transparent red colour. The fit against the reference SAXS data is from the left model. Please note the rotated xyz reference frame and model orientation with respect to (e) which was applied here for reasons of clarity.

Journal logoBIOLOGICAL
ISSN: 1399-0047
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