C 3

1. A B 2700 290 390 3100 4300 390 750 4800 N1/2B N1/2A O1 O2 C3 C2 C1 O2 C3 C2 C1 O1 1200 150 2900 1600 1000 130 2500 1700 0.8 30 2 0.5 50 10 9 2.2 D1 D2 D1 D2 4600* 270 410 3600 4500 460 900* 4300 N1Δ/2B N1Δ/2A O2 C3 C2 C1 O O1 O2 C3 C2 C1 970 160 3300 1500 1800* 120 2000* 1300 30 0.8 0.4 3 23* 3 13 22 D1 D2 D1 D2 1500 4000 130* 170* 680 4300 320* 3500 N1/2BΔ N1/2AΔ O1 O2 O2 C3 C2 C1 C3 C2 C1 O1 450* 520 60* 110 2600 1100* 3700 680 0.2 0.6 10* 9* 19* 4 7* 16 D1 D2 D1 D2 3800 180* 1600 640 3500* 110* 350 3900 N1Δ/2AΔ N1Δ/2BΔ O2 O2 C3 C2 C1 O1 C3 C2 C1 O1 340* 110 3200 730 2400 90 1400 480 0.2 20* 0.4* 19* 6* 9 6 17 D1 D2 D1 D2 Figure S1: Reaction mechanisms of NRs lacking CTDs alter channel kinetics. Kinetic models optimized by fitting 5C2O open state models to entire records obtained from 2A and 2B receptors. (p > 0.05). Rate constants (s-1) are given as rounded averages of means for each condition. * indicates values that are significantly different (lower in red and higher in blue) than the respective wild-type channels (p < 0.05).

2. Table S1: Kinetic analyses of open intervals. Time constants () and areas (a) of individual open components estimated by fitting entire files to a kinetic model containing 5C4) states. Values in blueare significantly higher than WT (*, p < 0.05)

3. Table S2: Kinetic analyses of closed intervals Time constants () and areas (a) of individual closed components (E1-E5) estimated by fitting entire files to a kinetic model containing 5C4O states. *, values that are significantly different relative to WT (p < 0.05), highlighted in red (lower) or blue(higher)