Projects per year
Abstract
Nitrate and nitrite transport across biological membranes is often facilitated by protein transporters that are members of the major facilitator superfamily. Paracoccus denitrificans contains an unusual arrangement whereby two of these transporters, NarK1 and NarK2, are fused into a single protein, NarK, which delivers nitrate to the respiratory nitrate reductase and transfers the product, nitrite, to the periplasm. Our complementation studies, using a mutant lacking the nitrate/proton symporter NasA from the assimilatory nitrate reductase pathway, support that NarK1 functions as a nitrate/proton symporter while NarK2 is a nitrate/nitrite antiporter. Through the same experimental system, we find that Escherichia coli NarK and NarU can complement deletions in both narK and nasA in P. denitrificans, suggesting that, while these proteins are most likely nitrate/nitrite antiporters, they can also act in the net uptake of nitrate. Finally, we argue that primary sequence analysis and structural modelling do not readily explain why NasA, NarK1 and NarK2, as well as other transporters from this protein family, have such different functions, ranging from net nitrate uptake to nitrate/nitrite exchange. This article is protected by copyright. All rights reserved.explain why NasA, NarK1 and NarK2, as well as other transporters from this protein family, have such different functions, ranging from net nitrate uptake to nitrate/nitrite exchange.
Original language | English |
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Pages (from-to) | 117–133 |
Number of pages | 17 |
Journal | Molecular Microbiology |
Volume | 103 |
Issue number | 1 |
Early online date | 3 Oct 2016 |
DOIs | |
Publication status | Published - Jan 2017 |
Keywords
- nitrate
- transport
- Paracoccus denitrificans
- NarK
- NasA
Profiles
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Andrew Gates
- School of Biological Sciences - Associate Professor in Bacterial Bioenergetics
- Centre for Molecular and Structural Biochemistry - Member
- Molecular Microbiology - Member
Person: Research Group Member, Research Centre Member, Academic, Teaching & Research
Projects
- 1 Finished
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Elucidating novel pathways and regulation of nitrogen assimilation in alpha proteobacteria exemplified by the soil organism Paracoccus denitrificans
Richardson, D. & Ferguson (Oxford), S. J.
Biotechnology and Biological Sciences Research Council
1/01/08 → 31/05/11
Project: Research