ArticleProceedings of the National Academy of Sciences of the United States of America2008
Substrate binding, deprotonation, and selectivity at the periplasmic entrance of the Escherichia coli ammonia channel AmtB.
Article in Proceedings of the National Academy of Sciences of the United States of America, 2008. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 41 papers.
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Who cites it
41 citing papers in PubMed, 83 citations in OpenAlex.
- Metabolic engineering strategies for sustainable de novo isobutylamine production by Corynebacterium glutamicum.Biotechnology for biofuels and bioproducts · 2026Article
- Biological ammonium transporters from the Amt/Mep/Rh superfamily: mechanism, energetics, and technical limitations.Bioscience reports · 2024Review
- Prokaryotic ammonium transporters: what has three decades of research revealed?Microbiology (Reading, England) · 2023Article
- Local Attraction of Substrates and Co-Substrates Enhances Weak Acid and Base Transmembrane Transport.Biomolecules · 2022Review
- Exaggerated trans-membrane charge of ammonium transporters in nutrient-poor marine environments.Open biology · 2022Article
- Is the E. coli Homolog of the Formate/Nitrite Transporter Family an Anion Channel? A Computational Study.Biophysical journal · 2020Article
- Functional Characterization of theFrontiers in plant science · 2020Article
- A pore-occluding phenylalanine gate prevents ion slippage through plant ammonium transporters.Scientific reports · 2019Article
- The lipid environment determines the activity of the Escherichia coli ammonium transporter AmtB.FASEB journal : official publication of the Federation of American Societies for Experimental Biology · 2019Article
- Posttranslational modification of dinitrogenase reductase in Rhodospirillum rubrum treated with fluoroacetate.World journal of microbiology & biotechnology · 2018Article
- The ctenidium of the giant clam, Tridacna squamosa, expresses an ammonium transporter 1 that displays light-suppressed gene and protein expression and may be involved in ammonia excretion.Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology · 2018Article
- Kinetics and structural features of dimeric glutamine-dependent bacterial NADThe Journal of biological chemistry · 2018Article
- Molecular characterization of two Rhesus glycoproteins from the euryhaline freshwater white-rimmed stingray, Himantura signifer, and changes in their transcript levels and protein abundance in the gills, kidney, and liver during brackish water acclimation.Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology · 2017Article
- Phylogenetic, structural, and functional characterization of AMT3;1, an ammonium transporter induced by mycorrhization among model grasses.Mycorrhiza · 2017Article
- Mechanism of formate-nitrite transporters by dielectric shift of substrate acidity.The EMBO journal · 2017Article
- Perfused Gills Reveal Fundamental Principles of pH Regulation and Ammonia Homeostasis in the CephalopodFrontiers in physiology · 2017Article
- Structural determinants of NH3 and NH4+ transport by mouse Rhbg, a renal Rh glycoprotein.American journal of physiology. Renal physiology · 2016Article
- Article
- Direct observation of electrogenic NH4(+) transport in ammonium transport (Amt) proteins.Proceedings of the National Academy of Sciences of the United States of America · 2014Article
- Uncoupling of ionic currents from substrate transport in the plant ammonium transporter AtAMT1;2.The Journal of biological chemistry · 2014Article
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Authors and funding
6 authors at 3 institutions in 3 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The conduction mechanism of Escherichia coli AmtB, the structurally and functionally best characterized representative of the ubiquitous Amt/Rh family, has remained controversial in several aspects. The predominant view has been that it facilitates the movement of ammonium in its uncharged form as indicated by the hydrophobic nature of a pore located in the center of each subunit of the homotrimer. Using site-directed mutagenesis and a combination of biochemical and crystallographic methods, we have investigated mechanistic questions concerning the putative periplasmic ammonium ion binding site S1 and the adjacent periplasmic "gate" formed by two highly conserved phenylalanine residues, F107 and F215. Our results challenge models that propose that NH(4)(+) deprotonation takes place at S1 before NH(3) conduction through the pore. The presence of S1 confers two critical features on AmtB, both essential for its function: ammonium scavenging efficiency at very low ammonium concentration and selectivity against water and physiologically important cations. We show that AmtB activity absolutely requires F215 but not F107 and that removal or obstruction of the phenylalanine gate produces an open but inactive channel. The phenyl ring of F215 must thus play a very specific role in promoting transfer and deprotonation of substrate from S1 to the central pore. We discuss these results with respect to three distinct mechanisms of conduction that have been considered so far. We conclude that substrate deprotonation is an essential part of the conduction mechanism, but we do not rule out net electrogenic transport.
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