title: Electron and atomic force microscopy of the trimeric ammonium transporter AmtB.
abstract: Escherichia coli AmtB is an archetypal member of the ammonium transporter (Amt) family, a family of proteins that are conserved in all domains of life. Reconstitution of AmtB in the presence of lipids produced large, ordered two-dimensional crystals. From these, a 12 A resolution projection map was determined by cryoelectron microscopy, and high-resolution topographs were acquired using atomic force microscopy. Both techniques showed the trimeric structure of AmtB in which each monomer seems to have a pseudo-two-fold symmetry. This arrangement is likely to represent the in vivo structure. This work provides the first views of the structure of any member of the Amt family.
authors.affiliation: Department of Molecular Biology and Biotechnology, Krebs Institute for Biomolecular Research, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Conroy
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Jamieson
authors.forename: Daniel
authors.initials: D
authors.lastname: Blakey
authors.forename: Thomas
authors.initials: T
authors.lastname: Kaufmann
authors.forename: Andreas
authors.initials: A
authors.lastname: Engel
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Fotiadis
authors.forename: Mike
authors.initials: M
authors.lastname: Merrick
authors.forename: Per A
authors.initials: PA
authors.lastname: Bullough
mesh_terms: D027682:Cation Transport Proteins / Q000737:chemistry*; D020285:Cryoelectron Microscopy; D003460:Crystallization; D004926:Escherichia coli; D029968:Escherichia coli Proteins / Q000737:chemistry*; D018625:Microscopy, Atomic Force
chemical_list: C111096:AmtB protein, E coli; D027682:Cation Transport Proteins; D029968:Escherichia coli Proteins