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dc.contributor.authorYasui, Masato
dc.contributor.authorHazama, Akihiro
dc.contributor.authorAgre, Peter
dc.contributor.authorKato, Yasuhiro
dc.contributor.authorKozono, David
dc.contributor.authorLiu, Kun
dc.date.accessioned2010-03-09T15:49:48Z
dc.date.available2010-03-09T15:49:48Z
dc.date.issued2005-02-08
dc.identifier.citationProc Natl Acad Sci U S A. 2005 Feb 8;102(6):2192-7. Epub 2005 Jan 25. http://www.pnas.org/content/102/6/2192.fullen_US
dc.identifier.urihttp://jhir.library.jhu.edu/handle/1774.2/33941
dc.description.abstractAquaporin (AQP) 6 belongs to the aquaporin water channel family. Unlike other aquaporins, AQP6 functions not as a water channel but as an anion-selective channel. Single-channel analyses have shown AQP6 to flicker rapidly between closed and open status. The atomic structure of AQP1 and amino acid sequence alignments of the mammalian aquaporins reveal two well conserved glycine residues: Gly-57 in transmembrane helix (TM) 2 and Gly-173 in TM5 reside at the contact point where the two helices cross in human AQP1. Uniquely, all known mammalian orthologs of AQP6 have an asparagine residue (Asn-60) at the position corresponding to Gly-57. Here we show that a single residue substitution (N60G in rat AQP6) totally eliminates the anion permeability of AQP6 when expressed in Xenopus oocytes, but the N60G oocytes exhibit significantly higher osmotic water permeability under basal conditions. Replacement of the glycine at this site in AQP0, AQP1, and AQP2 blocked expression of the mutants at the oocyte plasma membrane. We propose that the asparagine residue at the contact point between TM2 and TM5 in AQP6 may function as a teeter board needed for rapid structural oscillations during anion permeation.en_US
dc.language.isoen_USen_US
dc.publisherNational Academy of Sciencesen_US
dc.subjectWateren_US
dc.subjectIon channels/metabolismen_US
dc.subjectIon Channels/geneticsen_US
dc.subjectIon Channels/chemistryen_US
dc.subjectAquaporins/metabolismen_US
dc.subjectAquaporins/geneticsen_US
dc.subjectAquaporins/chemistryen_US
dc.subjectAmino Acid Substitutionen_US
dc.titleConversion of aquaporin 6 from an anion channel to a water-selective channel by a single amino acid substitutionen_US
dc.typeArticleen_US


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