Stability of LHI-RC complex (a), LeuT (b) and β2AR
(c,d) solubilized in PPM or DDM. LHI-RC stability was assessed by monitoring the
absorbance of the complexes at 875 nm (A875) at regular intervals
during a 20-day incubation. LeuT stability was assessed by measuring the ability
of the transporter to bind the radio-labeled substrate (3[H]-leucine
(Leu)) at regular intervals during a 12-day incubation at room temperature
via scintillation proximity assay (SPA).
β2AR stability was assessed by measuring the receptor
ability to bind the radio-labelled antagonist ([3H]-dihydroalprenolol
(DHA)) during a 6-day incubation at room temperature (c) or by measuring the
melting temperature (Tm) of the receptor using CPM
assay (d). The detergents were tested at CMC+0.05 wt% for LHI-RC, CMC+0.04 wt%
for LeuT, 0.2 wt% (ligand binding assay; c) or 0.1 wt% (CPM assay; d) for
β2AR. As for the LHI-RC complex study, the incubation
temperature was increased to 35 °C after the first 10-day incubation at
room temperature. Error bars: SEM, n = 2 (LHI-RC);
n = 2–3 (LeuT); n = 3
(β2AR).