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Ammonium ion transport by the AMT/Rh homologue LeAMT1;1

Mayer, Maria ; Dynowski, Marek ; Ludewig, Uwe (2006)
Ammonium ion transport by the AMT/Rh homologue LeAMT1;1.
In: The Biochemical journal, 396 (3)
Artikel, Bibliographie

Kurzbeschreibung (Abstract)

AMT (ammonium transporter)/Rh (Rhesus) ammonium transporters/channels are identified in all domains of life and fulfil contrasting functions related either to ammonium acquisition or excretion. Based on functional and crystallographic high-resolution structural data, it was recently proposed that the bacterial AmtB (ammonium transporter B) is a gas channel for NH3 [Khademi, O'Connell, III, Remis, Robles-Colmenares, Miercke and Stroud (2004) Science 305, 1587-1594; Zheng, Kostrewa, Berneche, Winkler and Li (2004) Proc. Natl. Acad. Sci. U.S.A. 101, 17090-17095]. Key residues, proposed to be crucial for NH3 conduction, and the hydrophobic, but obstructed, pore were conserved in a homology model of LeAMT1;1 from tomato. Transport by LeAMT1;1 was affected by mutations of residues that were predicted to constitute the aromatic recruitment site for NH4+ at the external pore entrance. Despite the structural similarities, LeAMT1;1 was shown to transport only the ion; each transported 14C-methylammonium molecule carried a single positive elementary charge. Similarly, NH4+ (or H+/NH3) was transported, but NH3 conduction was excluded. It is concluded that related proteins and a similar molecular architecture can apparently support contrasting transport mechanisms.

Typ des Eintrags: Artikel
Erschienen: 2006
Autor(en): Mayer, Maria ; Dynowski, Marek ; Ludewig, Uwe
Art des Eintrags: Bibliographie
Titel: Ammonium ion transport by the AMT/Rh homologue LeAMT1;1
Sprache: Englisch
Publikationsjahr: 2006
Titel der Zeitschrift, Zeitung oder Schriftenreihe: The Biochemical journal
Jahrgang/Volume einer Zeitschrift: 396
(Heft-)Nummer: 3
Kurzbeschreibung (Abstract):

AMT (ammonium transporter)/Rh (Rhesus) ammonium transporters/channels are identified in all domains of life and fulfil contrasting functions related either to ammonium acquisition or excretion. Based on functional and crystallographic high-resolution structural data, it was recently proposed that the bacterial AmtB (ammonium transporter B) is a gas channel for NH3 [Khademi, O'Connell, III, Remis, Robles-Colmenares, Miercke and Stroud (2004) Science 305, 1587-1594; Zheng, Kostrewa, Berneche, Winkler and Li (2004) Proc. Natl. Acad. Sci. U.S.A. 101, 17090-17095]. Key residues, proposed to be crucial for NH3 conduction, and the hydrophobic, but obstructed, pore were conserved in a homology model of LeAMT1;1 from tomato. Transport by LeAMT1;1 was affected by mutations of residues that were predicted to constitute the aromatic recruitment site for NH4+ at the external pore entrance. Despite the structural similarities, LeAMT1;1 was shown to transport only the ion; each transported 14C-methylammonium molecule carried a single positive elementary charge. Similarly, NH4+ (or H+/NH3) was transported, but NH3 conduction was excluded. It is concluded that related proteins and a similar molecular architecture can apparently support contrasting transport mechanisms.

Fachbereich(e)/-gebiet(e): 10 Fachbereich Biologie > Pflanzenernährung und Biomasse
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10 Fachbereich Biologie
Hinterlegungsdatum: 16 Mär 2010 14:07
Letzte Änderung: 05 Mär 2013 09:32
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