1J4N

Crystal Structure of the AQP1 water channel

Summary for 1J4N

• Entry DOI: 10.2210/pdb1j4n/pdb
• Related: 1FQY
• Descriptor: AQUAPORIN 1, nonyl beta-D-glucopyranoside (3 entities in total)
• Functional Keywords: membrane protein, channel protein, transmembrane helices
• Biological source: Bos taurus (cattle)
• Total number of polymer chains: 1
• Total formula weight: 29743.56

Authors

Sui, H.,Han, B.-G.,Lee, J.K.,Walian, P.,Jap, B.K. (deposition date: 2001-10-19, release date: 2002-03-27, Last modification date: 2023-12-27)

Primary citation

Sui, H.,Han, B.G.,Lee, J.K.,Walian, P.,Jap, B.K.
Structural basis of water-specific transport through the AQP1 water channel.
Nature, 414:872-878, 2001

PubMed Abstract: Water channels facilitate the rapid transport of water across cell membranes in response to osmotic gradients. These channels are believed to be involved in many physiological processes that include renal water conservation, neuro-homeostasis, digestion, regulation of body temperature and reproduction. Members of the water channel superfamily have been found in a range of cell types from bacteria to human. In mammals, there are currently 10 families of water channels, referred to as aquaporins (AQP): AQP0-AQP9. Here we report the structure of the aquaporin 1 (AQP1) water channel to 2.2 A resolution. The channel consists of three topological elements, an extracellular and a cytoplasmic vestibule connected by an extended narrow pore or selectivity filter. Within the selectivity filter, four bound waters are localized along three hydrophilic nodes, which punctuate an otherwise extremely hydrophobic pore segment. This unusual combination of a long hydrophobic pore and a minimal number of solute binding sites facilitates rapid water transport. Residues of the constriction region, in particular histidine 182, which is conserved among all known water-specific channels, are critical in establishing water specificity. Our analysis of the AQP1 pore also indicates that the transport of protons through this channel is highly energetically unfavourable.

PubMed: 11780053
DOI: 10.1038/414872a

Experimental method

X-RAY DIFFRACTION (2.2 Å)