The ankyrin repeats of TRPV channels. Diagram shows the topology of TRPV channels with the relative position of the ankyrin repeats illustrated with the structure of the TRPV1 ARD. Only two of the four subunits are shown for clarity in yellow and green, respectively; the subunits in front and in back of the plane of the page are omitted. The transmembrane domains are illustrated using the homologous structure of the Shaker potassium channel (Long et al., 2005). The N- and C-terminal segments of unknown structure are depicted with shapes that approximate their relative size. ATP and ATP-interacting side chains are shown as sticks and colored according to atom type, and a transparent surface representation highlights the surface complementarity of the ATP and its binding site. The approximate size of those protein segments in numbers of amino acid (aa) residues is indicated for the green subunit. The transmembrane and ARDs of TRPV channels are each ∼250 amino acid residues. TRPV subunits typically are ∼800-residues long.