Extended Data Figure 1. Digitonin is a suitable detergent for the purification of GluA2 receptor – TARP γ 2 complex.

a, The receptor-TARP complex in digitonin disassociates when diluted into DDM. A complex composed of the GluA2 receptor and GFP-tagged TARP γ2 was diluted in digitonin (green) or DDM (red) before being subjected to GFP-tuned FSEC analysis. b, Coomassie blue-stained SDS-PAGE gel of the purified complex. c, Tryptophan-tuned FSEC profile of the purified complex was comprised of a major peak containing the tetrameric complex and a minor shoulder, the latter suggestive of either incompletely assembled or partially dissociated complexes. Only the full-size, tetrameric species was used for single particle cryo-EM analysis. d, A representative, motion-corrected micrograph of the GluA2 receptor – TARP γ2 complex is shown. A few distinct complexes with the characteristic capital Y shape of the non-desensitized state of the AMPA receptor are circled. e, Representative 2D-class averages showing a range of projections of the receptor – TARP γ2 complex.