Crystal structure of a yeast aquaporin at 1.15 angstrom reveals a novel gating mechanism.
Artikel i vetenskaplig tidskrift, 2009

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 A 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.

Freezing

Models

Aquaporins

chemistry

metabolism

Tyrosine

Ion Channel Gating

Microbial Viability

Molecular

Secondary

metabolism

Crystallography

Pichia

Biological Transport

chemistry

Water

Structural Homology

Phosphorylation

chemistry

Spinacia oleracea

Protein Structure

Computer Simulation

Protein

X-Ray

Författare

Gerhard Fischer

Göteborgs universitet

Urszula Kosinska-Eriksson

Göteborgs universitet

Camilo Aponte-Santamaría

Madelene Palmgren

Göteborgs universitet

Cecilia Geijer

Göteborgs universitet

Kristina Hedfalk

Göteborgs universitet

Stefan Hohmann

Göteborgs universitet

Bert L de Groot

Richard Neutze

Göteborgs universitet

Karin Lindkvist-Petersson

Göteborgs universitet

PLoS Biology

1544-9173 (ISSN) 1545-7885 (eISSN)

Vol. 7 e1000130-

Ämneskategorier

Kemi

DOI

10.1371/journal.pbio.1000130

PubMed

19529756