Figure 5.

L124D STARD4 has weakened interactions with membranes. HSQC spectra of uniformly ¹⁵N-labeled wild-type STARD4 in the absence (A, black) and presence (C, red) of donor liposomes (total lipid concentration of 6 mM). HSQC spectra of L124D STARD4 in the absence (B, black) and presence (D, red) of 6 mM total donor lipids. (E) Ratio of signal intensity in the presence of 6 mM total donor lipids compared to the intensity in the absence of liposomes, averaged over 25 well-resolved amide resonances, for 50 μM wild-type and L124D STARD4. A loss of signal intensity in the presence of liposomes corresponds to binding to the liposomes, within the error of the NMR measurement. (F) Size exclusion chromatography plot for wild-type (left) or L124D (right) STARD4 in the absence (red) or presence (blue) of 15 mM total lipid.