Characterization of interactions between the terminal ribose of ADPR and the NUDT9-H domain. (A) Ribbon presentation of the terminal ribose binding pockets in the NUDT9-H domain (gray). The interactions are denoted with yellow dashed lines. (B and C) Characterization of the ADPR concentration–current response relationship for the WT (dashed line) and indicated mutants (continuous line) of the TRPM2 channels. Data are expressed as mean ± SEM from five independent repetitions. (D) The representative traces induced by 50 mM calcium in HEK293 blank cell, TRPM2, and G1389A mutant–transfected cells. (E) Summary of the currents in D. (F) The representative trace induced by 10 mM H₂O₂ in HEK293 blank cell, TRPM2, and G1389A mutant–transfected cells. (G) Summary of the currents in F). Data in E and G are expressed as mean ± SEM from at least six independent repetitions.