TCBG Seminar

Molecular Basis for the Water-specific Transport Mechanisms of AQP1 Water Channel

Professor Bing K. Jap
Life Sciences Division
Lawrence Berkeley National Laboratory
Berkeley, California

Monday, February 18, 2002
3:00 pm (CT)
3269 Beckman Institute


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. Defects of these proteins have been associated with a number of medical disorders such as Nephrogenic Diabetes Insipidus. The structure of AQP1 from bovine red blood cells at 2.2 ? resolution, as determined by x- ray crystallography, shows that the channel consists of an extracellular and a cytoplasmic vestibule connected by an extended narrow pore. The narrow pore contains a constriction filter that establishes the steric upper limit of the channel and three hydrophilic nodes that punctuate an otherwise extremely hydrophobic narrow pore. This channel design has revealed the basis for water transport specificity that utilizes both the size of the constriction and an appropriate combination of long hydrophobic pore and minimal number of water binding sites to facilitate water transport through the channel.

Tea and coffee will be served in R3151 Beckman Institute at 2:15pm.

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