Extended Data Fig. 7: Positive electrostatic potential below the lower gate.

a, The TRP helix forms an electric dipole with electro-positive K969 at the N terminus and electronegative carbonyl oxygens at the C terminus. b, When the A-loop is oriented in the up position, K671 is coordinated by the carbonyl oxygens at the C terminus of the TRP helix and increases its dipole moment to enhance the positive electrostatic potential at the N terminus. c, The C-terminal carbonyl oxygens of the TRP helix form a pocket that is unoccupied in the agonist-free channel. d, Coordination of K671 with the carbonyl oxygens at the TRP helix C terminus increases the positive electrostatic potential at the TRP helix N terminus. In silico substitution of K671 with glutamate decreases the electrostatic potential of the TRP helix. e, Conformational changes associated with pore dilation further increase the positive electrostatic potential of the TRP ___domain. f, Multiple sequence alignment of TRPA1 orthologues.