The conserved carboxy-terminal region of the ammonia channel AmtB plays a critical role in channel function

Emmanuele Severi, Arnaud Javelle, Mike Merrick

    Research output: Contribution to journalArticle

    15 Citations (Scopus)

    Abstract

    The ammonium transport (Amt) proteins are a highly conserved family of integral membrane proteins found in eubacteria, archaea, fungi and plants. Genetic, biochemical and bioinformatic analyses suggest that they have a common tertiary structure comprising eleven trans-membrane helices with an N-out, C-in topology. The cytoplasmic C-terminus is variable in length but includes a core region of some 22 residues with considerable sequence conservation. Previous studies have indicated that this C-terminus is not absolutely required for Amt activity but that mutations that alter C-terminal residues can have very marked effects. Using the Escherichia coli AmtB protein as a model system for Amt proteins, we have carried out an extensive site-directed mutagenesis study to investigate the possible role of this region of the protein. Our data indicate that nearly all mutations fall into two phenotypic classes that are best explained in terms of two distinct effects of the C-terminal region on AmtB activity. Residues within the C-terminus play a significant role in normal AmtB function and the C-terminal region might also mediate co-operativity between the three subunits of AmtB.
    Original languageEnglish
    Pages (from-to)161-71
    Number of pages11
    JournalMolecular Membrane Biology
    Volume24
    Issue number2
    DOIs
    Publication statusPublished - 2007

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    Ammonium Compounds
    Ammonia
    Carrier Proteins
    Mutation
    Escherichia coli Proteins
    Archaea
    Site-Directed Mutagenesis
    Computational Biology
    Molecular Biology
    Membrane Proteins
    Fungi
    Bacteria
    Membranes
    Proteins

    Cite this

    Severi, Emmanuele ; Javelle, Arnaud ; Merrick, Mike. / The conserved carboxy-terminal region of the ammonia channel AmtB plays a critical role in channel function. In: Molecular Membrane Biology. 2007 ; Vol. 24, No. 2. pp. 161-71.
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    abstract = "The ammonium transport (Amt) proteins are a highly conserved family of integral membrane proteins found in eubacteria, archaea, fungi and plants. Genetic, biochemical and bioinformatic analyses suggest that they have a common tertiary structure comprising eleven trans-membrane helices with an N-out, C-in topology. The cytoplasmic C-terminus is variable in length but includes a core region of some 22 residues with considerable sequence conservation. Previous studies have indicated that this C-terminus is not absolutely required for Amt activity but that mutations that alter C-terminal residues can have very marked effects. Using the Escherichia coli AmtB protein as a model system for Amt proteins, we have carried out an extensive site-directed mutagenesis study to investigate the possible role of this region of the protein. Our data indicate that nearly all mutations fall into two phenotypic classes that are best explained in terms of two distinct effects of the C-terminal region on AmtB activity. Residues within the C-terminus play a significant role in normal AmtB function and the C-terminal region might also mediate co-operativity between the three subunits of AmtB.",
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    The conserved carboxy-terminal region of the ammonia channel AmtB plays a critical role in channel function. / Severi, Emmanuele; Javelle, Arnaud; Merrick, Mike.

    In: Molecular Membrane Biology, Vol. 24, No. 2, 2007, p. 161-71.

    Research output: Contribution to journalArticle

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    AB - The ammonium transport (Amt) proteins are a highly conserved family of integral membrane proteins found in eubacteria, archaea, fungi and plants. Genetic, biochemical and bioinformatic analyses suggest that they have a common tertiary structure comprising eleven trans-membrane helices with an N-out, C-in topology. The cytoplasmic C-terminus is variable in length but includes a core region of some 22 residues with considerable sequence conservation. Previous studies have indicated that this C-terminus is not absolutely required for Amt activity but that mutations that alter C-terminal residues can have very marked effects. Using the Escherichia coli AmtB protein as a model system for Amt proteins, we have carried out an extensive site-directed mutagenesis study to investigate the possible role of this region of the protein. Our data indicate that nearly all mutations fall into two phenotypic classes that are best explained in terms of two distinct effects of the C-terminal region on AmtB activity. Residues within the C-terminus play a significant role in normal AmtB function and the C-terminal region might also mediate co-operativity between the three subunits of AmtB.

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