Fig. 3.

SAXS analysis. (A) Molecular parameters calculated from SAXS data. MM, R_g, D_max denote the molecular mass, radius of gyration, and maximum size, respectively. Parameters without superscripts are experimental values; superscripts AB, RB, and XT refer to ab initio and rigid-body fitted models (shown in D) and the crystal structure, respectively. MMcalc is the theoretical MM computed from the protein sequence. χ is the discrepancy between experimental data and those computed from models; (B) SAXS data are displayed as dots with error bars (grey), while curves computed from the crystallographic (blue) and the RB model shown in (D) (red) are given as solid lines; (C) Distance distribution function; (D) Ab initio (white spheres) and RB (red) models are shown superimposed on the crystal structure (blue). In this RB model, only domain Fn³¹ was permitted to vary its position, while the rest of the molecule was fixed; (E) R_g distributions for models from a random pool of 10⁵ structures (solid line) and optimized by EOM (dashed line).