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 6 e1000130-Ämneskategorier
Kemi
DOI
10.1371/journal.pbio.1000130
PubMed
19529756