An unusual twin: his arrangement in the pore of ammonia channels is essential for substrate conductance

Arnaud Javelle, Domenico Lupo, Lei Zheng, Xiao-Dan Li, Fritz K Winkler, Mike Merrick

    Research output: Contribution to journalArticle

    47 Citations (Scopus)

    Abstract

    Amt proteins constitute a class of ubiquitous integral membrane proteins that mediate movement of ammonium across cell membranes. They are homotrimers, in which each subunit contains a narrow pore through which substrate transport occurs. Two conserved histidine residues in the pore have been proposed to be necessary for ammonia conductance. By analyzing 14 engineered polar and non-polar variants of these histidines, in Escherichia coli AmtB, we show that both histidines are absolutely required for optimum substrate conductance. Crystal structures of variants confirm that substitution of the histidine residues does not affect AmtB structure. In a subgroup of Amt proteins, found only in fungi, one of the histidines is replaced by glutamate. The equivalent substitution in E. coli AmtB is partially active, and the structure of this variant suggests that the glutamate side chain can make similar interactions to those made by histidine.

    Original languageEnglish
    Pages (from-to)39492-8
    Number of pages7
    JournalJournal of Biological Chemistry
    Volume281
    Issue number51
    DOIs
    Publication statusPublished - 2006

    Fingerprint

    Ammonia
    Histidine
    Substrates
    Escherichia coli
    Glutamic Acid
    Substitution reactions
    Cell membranes
    Fungi
    Ammonium Compounds
    Membrane Proteins
    Proteins
    Crystal structure
    Cell Membrane

    Cite this

    Javelle, Arnaud ; Lupo, Domenico ; Zheng, Lei ; Li, Xiao-Dan ; Winkler, Fritz K ; Merrick, Mike. / An unusual twin : his arrangement in the pore of ammonia channels is essential for substrate conductance. In: Journal of Biological Chemistry. 2006 ; Vol. 281, No. 51. pp. 39492-8.
    @article{fad297676ffe4348aab1323e56d0e3f3,
    title = "An unusual twin: his arrangement in the pore of ammonia channels is essential for substrate conductance",
    abstract = "Amt proteins constitute a class of ubiquitous integral membrane proteins that mediate movement of ammonium across cell membranes. They are homotrimers, in which each subunit contains a narrow pore through which substrate transport occurs. Two conserved histidine residues in the pore have been proposed to be necessary for ammonia conductance. By analyzing 14 engineered polar and non-polar variants of these histidines, in Escherichia coli AmtB, we show that both histidines are absolutely required for optimum substrate conductance. Crystal structures of variants confirm that substitution of the histidine residues does not affect AmtB structure. In a subgroup of Amt proteins, found only in fungi, one of the histidines is replaced by glutamate. The equivalent substitution in E. coli AmtB is partially active, and the structure of this variant suggests that the glutamate side chain can make similar interactions to those made by histidine.",
    author = "Arnaud Javelle and Domenico Lupo and Lei Zheng and Xiao-Dan Li and Winkler, {Fritz K} and Mike Merrick",
    year = "2006",
    doi = "10.1074/jbc.M608325200",
    language = "English",
    volume = "281",
    pages = "39492--8",
    journal = "Journal of Biological Chemistry",
    issn = "0021-9258",
    publisher = "American Society for Biochemistry and Molecular Biology",
    number = "51",

    }

    An unusual twin : his arrangement in the pore of ammonia channels is essential for substrate conductance. / Javelle, Arnaud; Lupo, Domenico; Zheng, Lei; Li, Xiao-Dan; Winkler, Fritz K; Merrick, Mike.

    In: Journal of Biological Chemistry, Vol. 281, No. 51, 2006, p. 39492-8.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - An unusual twin

    T2 - his arrangement in the pore of ammonia channels is essential for substrate conductance

    AU - Javelle, Arnaud

    AU - Lupo, Domenico

    AU - Zheng, Lei

    AU - Li, Xiao-Dan

    AU - Winkler, Fritz K

    AU - Merrick, Mike

    PY - 2006

    Y1 - 2006

    N2 - Amt proteins constitute a class of ubiquitous integral membrane proteins that mediate movement of ammonium across cell membranes. They are homotrimers, in which each subunit contains a narrow pore through which substrate transport occurs. Two conserved histidine residues in the pore have been proposed to be necessary for ammonia conductance. By analyzing 14 engineered polar and non-polar variants of these histidines, in Escherichia coli AmtB, we show that both histidines are absolutely required for optimum substrate conductance. Crystal structures of variants confirm that substitution of the histidine residues does not affect AmtB structure. In a subgroup of Amt proteins, found only in fungi, one of the histidines is replaced by glutamate. The equivalent substitution in E. coli AmtB is partially active, and the structure of this variant suggests that the glutamate side chain can make similar interactions to those made by histidine.

    AB - Amt proteins constitute a class of ubiquitous integral membrane proteins that mediate movement of ammonium across cell membranes. They are homotrimers, in which each subunit contains a narrow pore through which substrate transport occurs. Two conserved histidine residues in the pore have been proposed to be necessary for ammonia conductance. By analyzing 14 engineered polar and non-polar variants of these histidines, in Escherichia coli AmtB, we show that both histidines are absolutely required for optimum substrate conductance. Crystal structures of variants confirm that substitution of the histidine residues does not affect AmtB structure. In a subgroup of Amt proteins, found only in fungi, one of the histidines is replaced by glutamate. The equivalent substitution in E. coli AmtB is partially active, and the structure of this variant suggests that the glutamate side chain can make similar interactions to those made by histidine.

    U2 - 10.1074/jbc.M608325200

    DO - 10.1074/jbc.M608325200

    M3 - Article

    C2 - 17040913

    VL - 281

    SP - 39492

    EP - 39498

    JO - Journal of Biological Chemistry

    JF - Journal of Biological Chemistry

    SN - 0021-9258

    IS - 51

    ER -