Fig. 5

Nanobodies reduce ATPase activity of CFTR but increase the temperature of thermal inactivation. a Influence of nanobody addition on ATPase activity of wt-CFTR. Conversion of α-³²P-ATP to ADP was measured after 1 h incubation of wt-CFTR with the different nanobodies. Data from replicate determinations are represented as mean ± SEM (n = 3, except for ATPase activity of wt-CFTR activity with nanobodies Neg and T4 for which n = 4). b Thermoprotection of wt-CFTR activity by nanobodies. Inactivation threshold temperatures were determined by measuring residual ATPase activity after 30 min heat challenge at various temperatures. Data from replicate determinations are represented as mean ± SEM (n = 3, except for wt-CFTR activity in absence of nanobody for which n = 4). c Thermostability of stab-CFTR measured by nanoDSF. First derivative of 350 nm fluorescence as a function of temperature showing the determination of Tm of purified stab-CFTR alone (black) or in complex with nanobody T2a (dark grey). Melting curve of nanobody T2a alone is depicted in light grey. One representative experiment shown. d Thermostability of stab-CFTR as in (c), in complex with nanobody T4 (dark grey). Melting curve of nanobody T4 alone is depicted in light grey. One representative experiment shown. e Summary of melting temperatures of stab-CFTR in complex with nanobodies T2a, T4 and T8 determined by nanoDSF. Data from triplicates are represented as mean ± SD (n = 2). Source data are provided as a Source Data file