Structural and functional significance of water permeation through cotransporters.

ABSTRACT: Membrane transporters, in addition to their major role as specific carriers for ions and small molecules, can also behave as water channels. However, neither the location of the water pathway in the protein nor their functional importance is known. Here, we map the pathway for water and urea through the intestinal sodium/glucose cotransporter SGLT1. Molecular dynamics simulations using the atomic structure of the bacterial transporter vSGLT suggest that water permeates the same path as Na⁺ and sugar. On a structural model of SGLT1, based on the homology structure of vSGLT, we identified and mutated residues lining the sugar transport pathway to cysteine. The mutants were expressed in Xenopus oocytes, and the unitary water and urea permeabilities were determined before and after

SUBMITTER: Zeuthen T 

PROVIDER: S-EPMC5098644 | biostudies-literature | 2016 Nov

REPOSITORIES: biostudies-literature