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J Membr Biol. 2017 Dec;250(6):629-639. doi: 10.1007/s00232-017-9988-4. Epub 2017 Sep 15.

Quantification of the Intracellular Life Time of Water Molecules to Measure Transport Rates of Human Aquaglyceroporins.

Author information

1
Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, 405 30, Göteborg, Sweden.
2
Department of Experimental Medical Science, Lund University, BMC C13, 221 84, Lund, Sweden.
3
Physical Chemistry, Lund University, P.O.B. 124, 22100, Lund, Sweden.
4
CR Development, AB, Naturvetarvägen 14, 22362, Lund, Sweden.
5
Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, 405 30, Göteborg, Sweden. Karin.Lindkvist@med.lu.se.
6
Department of Experimental Medical Science, Lund University, BMC C13, 221 84, Lund, Sweden. Karin.Lindkvist@med.lu.se.

Abstract

Orthodox aquaporins are transmembrane channel proteins that facilitate rapid diffusion of water, while aquaglyceroporins facilitate the diffusion of small uncharged molecules such as glycerol and arsenic trioxide. Aquaglyceroporins play important roles in human physiology, in particular for glycerol metabolism and arsenic detoxification. We have developed a unique system applying the strain of the yeast Pichia pastoris, where the endogenous aquaporins/aquaglyceroporins have been removed and human aquaglyceroporins AQP3, AQP7, and AQP9 are recombinantly expressed enabling comparative permeability measurements between the expressed proteins. Using a newly established Nuclear Magnetic Resonance approach based on measurement of the intracellular life time of water, we propose that human aquaglyceroporins are poor facilitators of water and that the water transport efficiency is similar to that of passive diffusion across native cell membranes. This is distinctly different from glycerol and arsenic trioxide, where high glycerol transport efficiency was recorded.

KEYWORDS:

Aquaglyceroporin; Aquaporin; NMR; P. pastoris; Water transport

PMID:
28914342
PMCID:
PMC5696491
DOI:
10.1007/s00232-017-9988-4
[Indexed for MEDLINE]
Free PMC Article

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