4EZD

Crystal Structure of the UT-B Urea Transporter from Bos Taurus Bound to Selenourea

Summary for 4EZD

• Entry DOI: 10.2210/pdb4ezd/pdb
• Related: 4EZC
• Descriptor: Urea transporter 1, selenourea, beta-D-glucopyranose, ... (6 entities in total)
• Functional Keywords: membrane protein, channel, urea transport, slc14, structural genomics, psi-biology, new york consortium on membrane protein structure, nycomps, transport protein
• Biological source: Bos taurus (bovine,cow,domestic cattle,domestic cow)
• Cellular location: Cell membrane; Multi-pass membrane protein: Q5QF96
• Total number of polymer chains: 3
• Total formula weight: 130869.45

Authors

Cao, Y.,Levin, E.J.,Zhou, M.,New York Consortium on Membrane Protein Structure (NYCOMPS) (deposition date: 2012-05-02, release date: 2012-06-27, Last modification date: 2024-02-28)

Primary citation

Levin, E.J.,Cao, Y.,Enkavi, G.,Quick, M.,Pan, Y.,Tajkhorshid, E.,Zhou, M.
Structure and permeation mechanism of a mammalian urea transporter.
Proc.Natl.Acad.Sci.USA, 109:11194-11199, 2012

PubMed Abstract: As an adaptation to infrequent access to water, terrestrial mammals produce urine that is hyperosmotic to plasma. To prevent osmotic diuresis by the large quantity of urea generated by protein catabolism, the kidney epithelia contain facilitative urea transporters (UTs) that allow rapid equilibration between the urinary space and the hyperosmotic interstitium. Here we report the first X-ray crystal structure of a mammalian UT, UT-B, at a resolution of 2.36 Å. UT-B is a homotrimer and each protomer contains a urea conduction pore with a narrow selectivity filter. Structural analyses and molecular dynamics simulations showed that the selectivity filter has two urea binding sites separated by an approximately 5.0 kcal/mol energy barrier. Functional studies showed that the rate of urea conduction in UT-B is increased by hypoosmotic stress, and that the site of osmoregulation coincides with the location of the energy barrier.

PubMed: 22733730
DOI: 10.1073/pnas.1207362109

Experimental method

X-RAY DIFFRACTION (2.5 Å)