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The substrate-binding protein imposes directionality on an electrochemical sodium gradient-driven TRAP transporter

Mulligan, Christopher, Geertsma, Eric R, Severi, Emmanuele, Kelly, David J, Poolman, Bert, Thomas, Gavin H (2009) The substrate-binding protein imposes directionality on an electrochemical sodium gradient-driven TRAP transporter. Proceedings of the National Academy of Sciences of the United States of America, 106 (6). pp. 1778-1783. ISSN 1091-6490. (doi:10.1073/pnas.0809979106) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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Official URL
http://dx.doi.org/10.1073/pnas.0809979106

Abstract

Substrate-binding protein-dependent secondary transporters are widespread in prokaryotes and are represented most frequently by members of the tripartite ATP-independent periplasmic (TRAP) transporter family. Here, we report the membrane reconstitution of a TRAP transporter, the sialic acid-specific SiaPQM system from Haemophilus influenzae, and elucidate its mechanism of energy coupling. Uptake of sialic acid via membrane-reconstituted SiaQM depends on the presence of the sialic acid-binding protein, SiaP, and is driven by the electrochemical sodium gradient. The interaction between SiaP and SiaQM is specific as transport is not reconstituted using the orthologous sialic acid-binding protein VC1779. Importantly, the binding protein also confers directionality on the transporter, and reversal of sialic acid transport from import to export is only possible in the presence of an excess of unliganded SiaP.

Item Type: Article
DOI/Identification number: 10.1073/pnas.0809979106
Uncontrolled keywords: sialic acid, SiaPQM, tripartite ATP-independent periplasmic transporter, Haemophilus influenzae, receptor-dependent translocation
Subjects: Q Science > QD Chemistry > QD431 Organic Chemistry- Biochemistry- Proteins, peptides, amino acids
Divisions: Faculties > Sciences > School of Biosciences
Depositing User: Christopher Mulligan
Date Deposited: 10 May 2017 14:44 UTC
Last Modified: 06 Feb 2020 04:16 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/61668 (The current URI for this page, for reference purposes)
Mulligan, Christopher: https://orcid.org/0000-0001-5157-4651
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