Fig. 3.

NMR analysis and comparison of native and mutant DI spectra. Superposition of the 2D ¹⁵N,¹H HSQC spectra of (A) D8S/D9G and (B) R39S (red contours) with that of native DI (black contours) of β₂GPI. Inserts show a backbone Cα tracing of the β₂GPI DI structure highlighting the site of mutation (red spheres) and residues whose cross peaks are shifted in the spectrum of the mutant protein by greater than the cross peak linewidth (yellow spheres). Note that the majority of cross peaks are not shifted by the mutations, and that the shifts are for residues local to the mutation site, indicating maintenance of the overall 3D fold of the variant proteins. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of the article.)