Fig. 3.

Sequence alignment of TRPV channel family members. Residues discussed in the text are bolded and colored. Numbers above and below the sequences refer to the human TRPV1 (hTRPV1) channel and the purple bacterial reaction center (PBRC) from Rhodobacter sphaeroides, respectively. The segment of PBRC from V220 to L227 can be aligned with either the S2–S3 linker/S3 or the S4–S5 linker of TRPV1. The critical residues for stimulatory non-swapping vanilloid bridges 1 and 2 and swapping bridge 3 are indicated in red while those for the silent swapping vanilloid bridges 1 and 2 are shown in blue. The residues shared by both silent and stimulatory vanilloid bridges are indicated in purple. Three anchors are proposed for a vanilloid compound to bind during the formation of the stimulatory and silent vanilloid bridges. The anchor T550 (T551 in mTRPV1) in S4 is arrowed in red while the anchor S512 (S513 in mTRPV1) in S3 and the anchor T671 (T670 in rTRPV1) in S6 are arrowed in purple. The black dash line separates two subunits of TRPV channels. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)