Fig. 3: SAF312 binding site in hTRPV1.
From: Structural basis of TRPV1 inhibition by SAF312 and cholesterol
a A closeup side view is shown for the detailed interactions between hTRPV1 and SAF312. The side chains of crucial residues involved in the interaction with SAF312 are shown in the sticks. b The sequence alignment of human TRPV channels is presented, with residues color-coded based on sequence similarity. Highly conserved residues are shown in blue, and less conserved residues are depicted in red. Residues that contribute to SAF312 binding and the corresponding domain are labeled. c, d Curve fitting (c) and IC50 (d) of SAF312 dose-dependent inhibition on different hTRPV1 mutants evoked by 3.33 μM capsaicin (n = 3 for E570Q; n = 4 for A566S and R557K respectively), data are shown as mean ± SD for c. e, f hTRPV1-Y511F expressing HEKT293 cells exposed to pH 5 solution alone, pH 5 solution with 0.1 μM SAF312 following approximately 30 s preincubation with 0.1 μM SAF312, and pH 5 solution with 3 μM SAF312 following around 30 s preincubation with 3 μM SAF312. I-V curves were generated from the peak currents (peak1, peak2, and peak3) at each stimulation time. g SAF312 dose-dependent curves in responding to pH 5 solution for HEK293T cells expressing hTRPV1WT (black), Y511F (blue), T550L (orange), T556A (green), or N551A (purple) (n = 4 at each concentration point). The currents at +80 mV induced by acid (pH 5) with different concentrations of SAF312 were normalized to the current induced by pH 5 alone (peak1). The series points were fitted with the Hill equation except for data from N551A exhibiting a connecting curve. The best-fitted IC50 values for WT, Y511F, T550L, and T556A were 0.69 μM, 4.02 μM, 0.60 μM, and 0.86 μM, respectively. Data were shown as mean ± SEM. h, i hTRPV1-T550L expressing HEKT293 cells exposed to pH 5 solution alone, pH 5 solution with 0.1 μM SAF312 following ~30 s preincubation with 0.1 μM SAF312, and pH 5 solution with 3 μM SAF312 following around 30 s preincubation with 3 μM SAF312. I-V curves were generated from the peak currents (peak1, peak2, and peak3) at each stimulation time. j Per residues contribution for SAF312 calculated by MM/GBSA (n = 3), data were shown as mean ± SD.
