Architecture and Selectivity in Aquaporins: 2.5 Å X-Ray Structure of Aquaporin Z
Open Access
- 22 December 2003
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLoS Biology
- Vol. 1 (3), e72
- https://doi.org/10.1371/journal.pbio.0000072
Abstract
Aquaporins are a family of water and small molecule channels found in organisms ranging from bacteria to animals. One of these channels, the E. coli protein aquaporin Z (AqpZ), has been shown to selectively conduct only water at high rates. We have expressed, purified, crystallized, and solved the X-ray structure of AqpZ. The 2.5 Å resolution structure of AqpZ suggests aquaporin selectivity results both from a steric mechanism due to pore size and from specific amino acid substitutions that regulate the preference for a hydrophobic or hydrophilic substrate. This structure provides direct evidence on the molecular mechanisms of specificity between water and glycerol in this family of channels from a single species. It is to our knowledge the first atomic resolution structure of a recombinant aquaporin and so provides a platform for combined genetic, mutational, functional, and structural determinations of the mechanisms of aquaporins and, more generally, the assembly of multimeric membrane proteins.This publication has 31 references indexed in Scilit:
- Structure and Mechanism of the Lactose Permease of Escherichia coliScience, 2003
- Lipids in the Structure, Folding, and Function of the KcsA K+ ChannelBiochemistry, 2002
- Comparative Protein Structure Modeling of Genes and GenomesAnnual Review of Biophysics and Biophysical Chemistry, 2000
- Statistical analysis of amino acid patterns in transmembrane helices: the GxxxG motif occurs frequently and in association with β-branched residues at neighboring positionsJournal of Molecular Biology, 2000
- Structural clues in the sequences of the aquaporinsJournal of Molecular Biology, 2000
- Structure of the water channel AqpZ from Escherichia coli revealed by electron crystallographyJournal of Molecular Biology, 1999
- Functional reconstitution and characterization of AqpZ, the E. coli water channel proteinJournal of Molecular Biology, 1999
- The Structure of the Potassium Channel: Molecular Basis of K + Conduction and SelectivityScience, 1998
- [20] Processing of X-ray diffraction data collected in oscillation modeMethods in Enzymology, 1997
- Over-production of Proteins inEscherichia coli: Mutant Hosts that Allow Synthesis of some Membrane Proteins and Globular Proteins at High LevelsJournal of Molecular Biology, 1996