title: Crystal structures explain functional properties of two E. coli porins.
abstract: Porins form aqueous channels that aid the diffusion of small hydrophilic molecules across the outer membrane of Gram-negative bacteria. The crystal structures of matrix porin and phosphoporin both reveal trimers of identical subunits, each subunit consisting of a 16-stranded anti-parallel beta-barrel containing a pore. A long loop inside the barrel contributes to a constriction of the channel where the charge distribution affects ion selectivity. The structures explain at the molecular level functional characteristics and their alterations by known mutations.
authors.affiliation: Department of Structural Biology, University of Basel, Switzerland.
authors.forename: S W
authors.initials: SW
authors.lastname: Cowan
authors.forename: T
authors.initials: T
authors.lastname: Schirmer
authors.forename: G
authors.initials: G
authors.lastname: Rummel
authors.forename: M
authors.initials: M
authors.lastname: Steiert
authors.forename: R
authors.initials: R
authors.lastname: Ghosh
authors.forename: R A
authors.initials: RA
authors.lastname: Pauptit
authors.forename: J N
authors.initials: JN
authors.lastname: Jansonius
authors.forename: J P
authors.initials: JP
authors.lastname: Rosenbusch
mesh_terms: D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000648:ultrastructure*; D003196:Computer Graphics; D003461:Crystallography; D004926:Escherichia coli / Q000648:ultrastructure*; D007473:Ion Channels / Q000502:physiology / Q000648:ultrastructure*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D018272:Porins; D011487:Protein Conformation; D012995:Solubility; D013329:Structure-Activity Relationship; D014867:Water; D014961:X-Ray Diffraction
chemical_list: D001425:Bacterial Outer Membrane Proteins; D007473:Ion Channels; D018272:Porins; D014867:Water