title: Role of the constriction loop in the gating of outer membrane porin PhoE of Escherichia coli.
abstract: Porins form voltage-gated channels in the bacterial outer membrane. These proteins are composed of three identical subunits, each forming a 16-stranded beta-barrel. In this study, the role in voltage gating of a loop that forms a constriction within the pore was studied. The channel characteristics of mutant PhoE porins, in which the tip of the constriction loop was connected to the barrel wall, were determined. Whereas the properties of several mutant channels were changed, all of these channels could still be closed at high potential, showing that a gross movement of the constriction loop within the channel is not implicated in voltage gating.
authors.affiliation: Department of Molecular Cell Biology and Institute of Biomembranes, Utrecht University, The Netherlands.
authors.forename: E F
authors.initials: EF
authors.lastname: Eppens
authors.forename: N
authors.initials: N
authors.lastname: Saint
authors.forename: P
authors.initials: P
authors.lastname: Van Gelder
authors.forename: R
authors.initials: R
authors.lastname: van Boxtel
authors.forename: J
authors.initials: J
authors.lastname: Tommassen
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism; D003001:Cloning, Molecular; D004553:Electric Conductivity; D004926:Escherichia coli / Q000737:chemistry* / Q000378:metabolism; D029968:Escherichia coli Proteins; D015640:Ion Channel Gating / Q000502:physiology; D007769:Lactams; D008081:Liposomes / Q000378:metabolism; D008958:Models, Molecular; D009154:Mutation; D018272:Porins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D017433:Protein Structure, Secondary
chemical_list: D000900:Anti-Bacterial Agents; D029968:Escherichia coli Proteins; D007769:Lactams; D008081:Liposomes; D018272:Porins; C082922:PhoE protein, E coli