The substrate-binding protein imposes directionality on an electrochemical sodium gradient-driven TRAP transporter
- 10 February 2009
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 106 (6), 1778-1783
- https://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.Keywords
This publication has 32 references indexed in Scilit:
- Structure, Function, and Evolution of Bacterial ATP-Binding Cassette SystemsMicrobiology and Molecular Biology Reviews, 2008
- High-throughput cloning and expression in recalcitrant bacteriaNature Methods, 2007
- Tripartite ATP-Independent Periplasmic Transporters: Application of a Relational Database for Genome-Wide Analysis of Transporter Gene Frequency and OrganizationMicrobial Physiology, 2007
- Crystal structures of an Extracytoplasmic Solute Receptor from a TRAP transporter in its open and closed forms reveal a helix-swapped dimer requiring a cation for α-keto acid bindingBMC Structural Biology, 2007
- Conservation of Structure and Mechanism in Primary and Secondary Transporters Exemplified by SiaP, a Sialic Acid Binding Virulence Factor from Haemophilus influenzaeJournal of Biological Chemistry, 2006
- Novel ligands for the extracellular solute receptors of two bacterial TRAP transportersMicrobiology, 2006
- ABC transporter architecture and regulatory roles of accessory domainsFEBS Letters, 2005
- Novel Sialic Acid Transporter of Haemophilus influenzaeInfection and Immunity, 2005
- ABC transporter architecture and mechanism: implications from the crystal structures of BtuCD and BtuFFEBS Letters, 2004
- The ATP/Substrate Stoichiometry of the ATP-binding Cassette (ABC) Transporter OpuAJournal of Biological Chemistry, 2003