Lycksell M,
Rovšnik U,
Bergh C,
Johansen N,
Martel A,
Porcar L,
Arleth L,
Howard R,
Lindahl E,
Proceedings of the National Academy of Sciences
118(37):e2108006118
(2021)
DOI
SASDL63 – Gloeobacter violaceus Ligand-Gated Ion Channel (GLIC) at pH 7.5 measured with cuvette-mode SANS
SANS data from solutions of Gloeobacter violaceus ligand-gated ion channel (GLIC) at pH 7.5 measured with cuvette-mode SANS in D2O, 20 mM Tris, 150 mM NaCl, and 0.5 mM matched-out deuterated DDM were collected on the D22 small-angle neutron scattering diffractometer at the Institut Laue-Langevin (ILL; Grenoble, France) using a Reuter-Stokes 3He detector at a wavelength of λ = 0.6 nm (I(s) vs s, where s = 4πsinθ/λ, and 2θ is the scattering angle). One solute concentration of 0.47 mg/ml was measured at 10°C. Two successive 1500 second frames were collected. The ion channel GLIC was expressed in Escherichia coli and purified using H2O based buffers and n-Dodecyl β-D-maltoside (DDM) detergent. The protein was exchanged to the D2O based buffer with deuterated DDM (d-DDM) in a gel filtration prior to the SANS measurement. The d-DDM has been deuterated to have the same scattering length density as D2O (matched-out deuteration). The exchanged sample was loaded into 2 mm Hellma quartz cuvettes and measured with a 2 m detector distance and a 11.2 m detector distance. Data reduction and buffer subtraction were performed using GRASP version 9.04, utilizing a dedicated buffer measurements for the buffer background. Data were corrected for the empty cuvette and background, and scaled by their transmission and thickness. They were scaled to absolute intensity by direct flux measurement. The intensities were scaled by the concentration estimated by UV-vis absorbance at 280 nm. In merging the data from the two detector distances, the data from 11.2 m was used up to 0.7 1/nm, above which the data from 2 m was used. A small additional constant was subtracted as a final adjustment to the background. Guinier analysis and molecular weight estimation were performed in Primus, selecting the Guinier range with Autorg and the Bayesian inference molecular weight. The pair-distance distribution was calculated using BayesApp (https://somo.chem.utk.edu/bayesapp/), set to fit the background and with no specified maximum diameter.
Storage temperature = UNKNOWN. Sample detector distance = UNKNOWN
s, nm-1
