Fig. 3. Conformational plasticity of serotonin-5HT₃R-Salipro state.

a Classes resulting from symmetry expanded monomer-focused 3D classification were divided into two groups based on comparison to the serotonin-5HT₃R-Salipro model: (1) densities similar to chain A/C (corresponding to ‘Mode 1’ in Fig. 2e) or M-type (left, model of chain C is shown), and (2) densities similar to chain B/D/E (Mode 2), or L-type (middle, model of chain D is shown). Superposition of M- and L-types with insert showing a top view (right). b Schematic showing the population of the eight different combinations of serotonin-5HT₃R-Salipro arrangements; blue and orange circles represent M- and L-type subunits, respectively. The largest class corresponds to the consensus serotonin-bound conformation.