+Search query
-Structure paper
Title | Structural analysis of the water channel AQP2 by single-particle cryo-EM. |
---|---|
Journal, issue, pages | J Struct Biol, Vol. 215, Issue 3, Page 107984, Year 2023 |
Publish date | Jun 12, 2023 |
Authors | Akiko Kamegawa / Shota Suzuki / Hiroshi Suzuki / Kouki Nishikawa / Nobutaka Numoto / Yoshinori Fujiyoshi / |
PubMed Abstract | Water channels, which are small membrane proteins almost entirely buried in lipid membranes, are challenging research targets for single-particle cryo-electron microscopy (cryo-EM), a powerful ...Water channels, which are small membrane proteins almost entirely buried in lipid membranes, are challenging research targets for single-particle cryo-electron microscopy (cryo-EM), a powerful technique routinely used to determine the structures of membrane proteins. Because the single-particle method enables structural analysis of a whole protein with flexible parts that interfere with crystallization, we have focused our efforts on analyzing water channel structures. Here, utilizing this system, we analyzed the structure of full-length aquaporin-2 (AQP2), a primary regulator of vasopressin-dependent reabsorption of water at the renal collecting ducts. The 2.9 Å resolution map revealed a cytoplasmic extension of the cryo-EM density that was presumed to be the highly flexible C-terminus at which the localization of AQP2 is regulated in the renal collecting duct cells. We also observed a continuous density along the common water pathway inside the channel pore and lipid-like molecules at the membrane interface. Observations of these constructions in the AQP2 structure analyzed without any fiducial markers (e.g., a rigidly bound antibody) indicate that single-particle cryo-EM will be useful for investigating water channels in native states as well as in complexes with chemical compounds. |
External links | J Struct Biol / PubMed:37315821 |
Methods | EM (single particle) |
Resolution | 2.89 Å |
Structure data | EMDB-29934, PDB-8gcl: |
Source |
|
Keywords | MEMBRANE PROTEIN / channel |