Structural and functional characterization of an otopetrin family proton channel.

ABSTRACT: The otopetrin (OTOP) proteins were recently characterized as proton channels. Here we present the cryo-EM structure of OTOP3 from Xenopus tropicalis (XtOTOP3) along with functional characterization of the channel. XtOTOP3 forms a homodimer with each subunit containing 12 transmembrane helices that can be divided into two structurally homologous halves; each half assembles as an α-helical barrel that could potentially serve as a proton conduction pore. Both pores open from the extracellular half before becoming occluded at a central constriction point consisting of three highly conserved residues - Gln_232/585-Asp₂₆₂/Asn₆₂₃-Tyr_322/666 (the constriction triads). Mutagenesis shows that the constriction triad from the second pore is less amenab

SUBMITTER: Chen Q 

PROVIDER: S-EPMC6483595 | biostudies-literature | 2019 Apr

REPOSITORIES: biostudies-literature