title: Confronting fusion protein-based membrane protein topology mapping with reality: the Escherichia coli ClcA H+/Cl- exchange transporter.
abstract: The topology of bacterial inner membrane proteins is commonly determined using topology reporters such as alkaline phosphatase and green fluorescent protein fused to a series of C-terminally truncated versions of the protein in question. Here, we report a detailed topology mapping of the Escherichia coli inner membrane H(+)/Cl(-) exchange transporter ClcA. Since the 3-D structure of ClcA is known, our results provide a critical test of the reporter fusion approach and offer new insights into the ClcA folding pathway.
authors.affiliation: Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: Marika
authors.initials: M
authors.lastname: Cassel
authors.forename: Susanna
authors.initials: S
authors.lastname: Seppälä
authors.forename: Gunnar
authors.initials: G
authors.lastname: von Heijne
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000595:Amino Acid Sequence; D017920:Antiporters / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism*; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000378:metabolism; D016623:Ion Pumps / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000378:metabolism*
chemical_list: D017920:Antiporters; C531144:ClcA protein, E coli; D029968:Escherichia coli Proteins; D016623:Ion Pumps; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D000469:Alkaline Phosphatase; C114089:phoA protein, E coli