Fig. 1: Cryo-EM structure of the secretin:SecR:DNGαsv2:Nb35 complex.
From: Structure and dynamics of the active Gs-coupled human secretin receptor
a Pharmacology of the expression construct for HA-SecR versus WT-SecR (WT-SecR, pEC50 11.0 ± 0.1; HA-SecR, pEC50 10.6 ± 0.2; n = 4). b SEC trace of post FLAG-affinity column elution (left panel), the complex peak (gray, dotted lines) was isolated and used for cryo-EM imaging, with the right panel illustrating stability of the complex following one cycle of freeze-thawing. c Coomassie stain of the purified complex separated by PAGE (right panel). d 3-D histogram representation of the Euler angle distribution of all the particles used in the reconstruction overlaid on the density map drawn on the same coordinate axis (shown from the front and 90° rotated). e Gold standard Fourier shell correlation (FSC) curves for the global, postprocessed map using a tight mask showing the overall nominal resolution of 2.3 Å. f Corrected FSC curves of maps using different masking: consensus refinement, postprocessed using a tight mask (excluding ECD and micelle, 2.3 Å, in purple), consensus refinement, postprocessed using a wide mask (2.4 Å, in cyan), and local refinement with using a receptor-only mask (2.5 Å, in gray). g Masks used for calculating FSC curves in f, displayed onto the global refinement map (colored according to f). h Local resolution-filtered EM map displaying local resolution (in Å) colored from highest resolution (blue) to lowest resolution (red) of the global map. i Local resolution-filtered EM map displaying local resolution (in Å) of the receptor-only refinement. j Global map (dark gray) overlaid with receptor-only map (gray transparent) containing the backbone model of the complex in ribbon format; SecR (dark green), secretin (dark red), G protein α-subunit (gold), β-subunit (cyan), γ-subunit (dark purple), and Nb35 (white). k Ribbon representation of the secretin:SecR:DNGαsv2:Nb35 complex colored according to j.
