Ammonium Ion Transport by the Amt/Rh Homologue Leamt1;1.
From: Zentrum für Molekularbiologie der Pflanzen (ZMBP), Pflanzenphysiologie, Universität Tübingen, Auf der Morgenstelle 1, 72076 Tübingen, Germany.
The Biochemical journal
- Publish Date: Jun 2006
- ISSN: 1470-8728
- Volume: 396
- Issue: 3
- Pages: 431-7
- Medium: Internet
- Language: English
- Citation (JAMA): Mayer Maria, Dynowski Marek, Ludewig Uwe, et al. Ammonium Ion Transport by the Amt/Rh Homologue Leamt1;1.. Biochem. J. Jun 2006;396:431-7
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.
Mesh Headings (Keywords): Animals, Cation Transport Proteins, Female, Methylamines, Mutation, Oocytes, Plant Proteins, Quaternary Ammonium Compounds, Xenopus
Check for Full Text / PubMed Unique Identifier (PMID): 16499477
This abstract is part of PubMed, a service of the U.S. National Library of Medicine. PubMed includes more than 17 million citations from MEDLINE and other life science journals for biomedical articles. See Copyright and Disclaimers.
Linked medical terms appearing on this page are added by Healia to help readers find more information and are not part of the original PubMed document.
The data herein was last updated on July 8th, 2008 and may not reflect the most current and accurate data available from NLM.