Proton-gated urea channel

The proton-gated urea channel is an inner-membrane protein essential for the survival to Helicobacter pylori. It enables the rapid influx of urea into the bacterium. It is closed at pH 7.0 and fully open at pH 5.0. Urease activity buffers the periplasm to pH 6.1. Using multiwavelength anomalous dispersion (MAD), its structure, a compact hexameric ring about 95 Å in diameter and 45 A ̊ in height, was determined. The centre is filled with a lipid plug that forms an asymmetric bilayer. Amino residues that can be protonated in the periplasmic domain are important for proton sensing or gating.^[1]

Acid-activated urea/amide channel
Urea channel hexamer (side view) from Helicobacter pylori
Identifiers
Symbol	UAC
Pfam	PF02293
TCDB	1.A.29
OPM superfamily	299
OPM protein	3ux4
Available protein structures: Pfam   structures / ECOD   PDB RCSB PDB; PDBe; PDBj PDBsum structure summary