Fig. 1: Structural characterization of [C − Mb][S].

The protein nanoconstruct was dissolved in H2O (gray squares), ChCl:Glyc (red triangles), TBAC:Glyc (blue circles), and TBAC:OA (green diamonds): a SRCD spectra, b SANS data and fits, and c UV-vis absorbance normalized to absorbance at 280 nm. For SANS characterization the solvents were deuterated, and isotopic labeling did not cause any significant change in protein behavior (Supplementary Note 2). The fits in (b) are presented for the entire q-range (black solid lines) and for the high q-expansion of the data (dashed lines). Data and models in (b) have been offset for clarity. Where not seen, error bars are within the markers. All data were recorded at 25 °C.