PDBsum entry 6poj

Transport protein

PDB id: 6poj

Contents

Protein chain

292 a.a.

PDB id:

6poj

Name:

Transport protein

Title:

Structural refinement of aquaporin 1 via ssnmr

Structure:

Aquaporin-1. Chain: a. Synonym: aqp-1,aquaporin-chip,urine water channel,water channel protein for red blood cells and kidney proximal tubule. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: aqp1, chip28. Expressed in: komagataella pastoris. Expression_system_taxid: 4922.

NMR struc:

10 models

Authors:

D.A.Dingwell,L.S.Brown,V.Ladizhansky

Key ref:

D.A.Dingwell et al. (2019). Structure of the Functionally Important Extracellular Loop C of Human Aquaporin 1 Obtained by Solid-State NMR under Nearly Physiological Conditions. J Phys Chem B, 123, 7700-7710. PubMed id: 31411472 DOI: 10.1021/acs.jpcb.9b06430

Date:

04-Jul-19 Release date: 02-Oct-19

Protein chain

P29972  (AQP1_HUMAN) -  Aquaporin-1 from Homo sapiens

Seq: 269 a.a.

Struc: 292 a.a.

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1021/acs.jpcb.9b06430

J Phys Chem B 123:7700-7710 (2019)

PubMed id: 31411472

Structure of the Functionally Important Extracellular Loop C of Human Aquaporin 1 Obtained by Solid-State NMR under Nearly Physiological Conditions.

D.A.Dingwell, L.S.Brown, V.Ladizhansky.

ABSTRACT

Human aquaporin 1 (hAQP1) is the first discovered selective water channel present in lipid membranes of multiple types of cells. Several structures of hAQP1 and its bovine homolog have been obtained by electron microscopy and X-ray crystallography, giving a consistent picture of the transmembrane domain with the water-conducting pore. The transmembrane domain is formed by six full helices and two half-helices, which form a central constriction with conserved asparagine-proline-alanine motifs. Another constriction, the aromatic/arginine (ar/R) filter, is found close to the extracellular surface, and includes aromatic residues and a conserved arginine (Arg-195). Although the existing crystal structures largely converge on the location of helical segments, they differ in details of conformation of the longest extracellular loop C and its interactions with the ar/R filter (in particular, with Arg-195). Here, we use solid-state nuclear magnetic resonance to determine multiple interatomic distances, and come up with a refined structural model for hAQP1, which represents a physiologically relevant state predominant at noncryogenic temperatures in a lipid environment. The model clearly disambiguates the position of the Arg-195 sidechain disputed previously and shows a number of interactions for loop C, both with the ar/R filter and a number of other residues on the extracellular side of hAQP1.