Advanced

Crystal structure of a yeast aquaporin at 1.15 Å reveals a novel gating mechanism

Fischer, Gerhard; Kosinska-Eriksson, Urszula; Aponte-Santamaría, Camilo; Palmgren, Madelene; Geijer, Cecilia; Hedfalk, Kristina; Hohmann, Stefan; de Groot, Bert L.; Neutze, Richard and Lindkvist-Petersson, Karin LU (2009) In PLoS Biology 7(6). p.1-13
Abstract

Aquaporins are transmembrane proteins that facilitate the flow of water through cellular membranes. An unusual characteristic of yeast aquaporins is that they frequently contain an extended N terminus of unknown function. Here we present the X-ray structure of the yeast aquaporin Aqy1 from Pichia pastoris at 1.15 Å resolution. Our crystal structure reveals that the water channel is closed by the N terminus, which arranges as a tightly wound helical bundle, with Tyr31 forming H-bond interactions to a water molecule within the pore and thereby occluding the channel entrance. Nevertheless, functional assays show that Aqy1 has appreciable water transport activity that aids survival during rapid freezing of P. pastoris. These findings... (More)

Aquaporins are transmembrane proteins that facilitate the flow of water through cellular membranes. An unusual characteristic of yeast aquaporins is that they frequently contain an extended N terminus of unknown function. Here we present the X-ray structure of the yeast aquaporin Aqy1 from Pichia pastoris at 1.15 Å resolution. Our crystal structure reveals that the water channel is closed by the N terminus, which arranges as a tightly wound helical bundle, with Tyr31 forming H-bond interactions to a water molecule within the pore and thereby occluding the channel entrance. Nevertheless, functional assays show that Aqy1 has appreciable water transport activity that aids survival during rapid freezing of P. pastoris. These findings establish that Aqy1 is a gated water channel. Mutational studies in combination with molecular dynamics simulations imply that gating may be regulated by a combination of phosphorylation and mechanosensitivity.

(Less)
Please use this url to cite or link to this publication:
author
publishing date
type
Contribution to journal
publication status
published
in
PLoS Biology
volume
7
issue
6
pages
1 - 13
publisher
Public Library of Science
external identifiers
  • scopus:67649963000
ISSN
1544-9173
DOI
10.1371/journal.pbio.1000130
language
English
LU publication?
no
id
ff217e41-68d3-40db-859d-a0125cfa98be
date added to LUP
2017-02-14 16:38:12
date last changed
2017-11-12 04:29:20
@article{ff217e41-68d3-40db-859d-a0125cfa98be,
  abstract     = {<p>Aquaporins are transmembrane proteins that facilitate the flow of water through cellular membranes. An unusual characteristic of yeast aquaporins is that they frequently contain an extended N terminus of unknown function. Here we present the X-ray structure of the yeast aquaporin Aqy1 from Pichia pastoris at 1.15 Å resolution. Our crystal structure reveals that the water channel is closed by the N terminus, which arranges as a tightly wound helical bundle, with Tyr31 forming H-bond interactions to a water molecule within the pore and thereby occluding the channel entrance. Nevertheless, functional assays show that Aqy1 has appreciable water transport activity that aids survival during rapid freezing of P. pastoris. These findings establish that Aqy1 is a gated water channel. Mutational studies in combination with molecular dynamics simulations imply that gating may be regulated by a combination of phosphorylation and mechanosensitivity.</p>},
  articleno    = {e1000130},
  author       = {Fischer, Gerhard and Kosinska-Eriksson, Urszula and Aponte-Santamaría, Camilo and Palmgren, Madelene and Geijer, Cecilia and Hedfalk, Kristina and Hohmann, Stefan and de Groot, Bert L. and Neutze, Richard and Lindkvist-Petersson, Karin},
  issn         = {1544-9173},
  language     = {eng},
  number       = {6},
  pages        = {1--13},
  publisher    = {Public Library of Science},
  series       = {PLoS Biology},
  title        = {Crystal structure of a yeast aquaporin at 1.15 Å reveals a novel gating mechanism},
  url          = {http://dx.doi.org/10.1371/journal.pbio.1000130},
  volume       = {7},
  year         = {2009},
}