Figure 2.

SAXS analysis indicates that purified VAR2CSA constructs are asymmetric and compactly folded.A–D, experimental scattering intensities (open circles) and calculated fit (black lines) as a function of the momentum transfer (q) for constructs with a single view of the averaged ab initio envelope (inset) (A) NTS-DBL6ε, black; (B) DBL1x-ID2a yellow; (C) DBL3x-DBL6ε, green; (D) DBL4ε-DBL6ε red. E, Guinier plot showing the fitted region as large filled circles (linear fit model; Pearson CC -0.99 for all constructs) and smaller open circles indicating data beyond the Guinier region, colored as in A–D. F, three orthogonal views of the ab initio envelopes of NTS-DBL6ε (gray mesh) reveal an asymmetric molecule with a larger broad base and smaller, narrower top. Ab initio envelopes for DBL1x-ID2a (yellow) and DBL3x-DBL6ε (green) show that the envelopes of the two deletion constructs account for the NTS-DBL6ε envelope within the limits of the resolution. For each construct, the averaged/filtered ab initio bead models were converted to a pseudo surfaces using Chimera (54).