Skip to main content
. 2020 Jun 18;10:9940. doi: 10.1038/s41598-020-66852-7

Figure 6.

Figure 6

Activity of HR and MsbA reconstituted in polymer-encased nanodiscs. (A) Cl−-induced HR spectral shift. Spectral shifts were elicited by increasing Cl− concentration from zero (black trace) to 250 mM by addition of NaCl (red trace). Examples of HR in proteoliposomes and 2:1 zSMALPs are shown. The intensity was normalized to the corresponding maximal intensity in 250 mM NaCl. The zSMALPs were prepared using 2:1 zSMA derived from RAFT P(St-ran-MA) copolymers with molecular weight of 6.4 kDa. See Supplementary Information for examples in detergent, 2:1 SMALPs, 1:1 zSMALPs and 2:1 M zSMALPs. (B) Cl−-induced HR spectral shifts summary. For each experiment, the wavelength at the maximal intensity was recorded in Cl−-free solution and after NaCl addition, and the differences are presented as means ± SEM (n = 3–4 per condition). The SMALPs, zSMALPs and M zSMALPs are the same as those described in Fig. 4. *Denotes P < 0.001 vs all other conditions. (C) MsbA ATPase activity. The ATPase activity of purified MsbA in 100 mM NaCl and 20 mM Tris/HCl, with 15% glycerol and 0.2 mM TCEP, pH 7.5, and 0.065% DDM and 0.04% sodium cholate (Det), or after reconstitution in liposomes (Proteoliposomes) or copolymer nanodiscs formed by 2:1 SMA (2:1 SMALPs), 1:1 zSMA (1:1 zSMALPs), 2:1 zSMA (2:1 zSMALPs), or 2:1 M zSMA (2:1 M zSMALPs). The SMALPs, zSMALPs and M zSMALPs are the same as those described in Fig. 4. Data are means ± SEM (n = 8–10 per condition), and were normalized to the average in Det (2.3 ± 0.1 ATP/s). *Denotes P < 0.001 vs Det; the activity in 2:1 SMALPs and 2:1 M zSMALPs was not different from zero.