Coupling substrate and ion binding to extracellular gate of a sodium-dependent aspartate transporter

Olga Boudker, Renae M. Ryan, Dinesh Yernool, Keiko Shimamoto, Eric Gouaux

Research output: Contribution to journalArticle

322 Citations (Scopus)

Abstract

Secondary transporters are integral membrane proteins that catalyse the movement of substrate molecules across the lipid bilayer by coupling substrate transport to one or more ion gradients, thereby providing a mechanism for the concentrative uptake of substrates. Here we describe crystallographic and thermodynamic studies of GltPh, a sodium (Na+)-coupled aspartate transporter, defining sites for aspartate, two sodium ions and d,l-threo-β-benzyloxyaspartate, an inhibitor. We further show that helical hairpin 2 is the extracellular gate that controls access of substrate and ions to the internal binding sites. At least two sodium ions bind in close proximity to the substrate and these sodium-binding sites, together with the sodium-binding sites in another sodium-coupled transporter, LeuT, define an unwound α-helix as the central element of the ion-binding motif, a motif well suited to the binding of sodium and to participation in conformational changes that accompany ion binding and unbinding during the transport cycle.

Original languageEnglish (US)
Pages (from-to)387-393
Number of pages7
JournalNature
Volume445
Issue number7126
DOIs
StatePublished - Jan 25 2007

Fingerprint

Aspartic Acid
Sodium
Ions
Binding Sites
Lipid Bilayers
Thermodynamics
Membrane Proteins

ASJC Scopus subject areas

  • General

Cite this

Coupling substrate and ion binding to extracellular gate of a sodium-dependent aspartate transporter. / Boudker, Olga; Ryan, Renae M.; Yernool, Dinesh; Shimamoto, Keiko; Gouaux, Eric.

In: Nature, Vol. 445, No. 7126, 25.01.2007, p. 387-393.

Research output: Contribution to journalArticle

Boudker, Olga ; Ryan, Renae M. ; Yernool, Dinesh ; Shimamoto, Keiko ; Gouaux, Eric. / Coupling substrate and ion binding to extracellular gate of a sodium-dependent aspartate transporter. In: Nature. 2007 ; Vol. 445, No. 7126. pp. 387-393.
@article{6c99b2e5a53142c7a368ece192b8d7c0,
title = "Coupling substrate and ion binding to extracellular gate of a sodium-dependent aspartate transporter",
abstract = "Secondary transporters are integral membrane proteins that catalyse the movement of substrate molecules across the lipid bilayer by coupling substrate transport to one or more ion gradients, thereby providing a mechanism for the concentrative uptake of substrates. Here we describe crystallographic and thermodynamic studies of GltPh, a sodium (Na+)-coupled aspartate transporter, defining sites for aspartate, two sodium ions and d,l-threo-β-benzyloxyaspartate, an inhibitor. We further show that helical hairpin 2 is the extracellular gate that controls access of substrate and ions to the internal binding sites. At least two sodium ions bind in close proximity to the substrate and these sodium-binding sites, together with the sodium-binding sites in another sodium-coupled transporter, LeuT, define an unwound α-helix as the central element of the ion-binding motif, a motif well suited to the binding of sodium and to participation in conformational changes that accompany ion binding and unbinding during the transport cycle.",
author = "Olga Boudker and Ryan, {Renae M.} and Dinesh Yernool and Keiko Shimamoto and Eric Gouaux",
year = "2007",
month = "1",
day = "25",
doi = "10.1038/nature05455",
language = "English (US)",
volume = "445",
pages = "387--393",
journal = "Nature",
issn = "0028-0836",
publisher = "Nature Publishing Group",
number = "7126",

}

TY - JOUR

T1 - Coupling substrate and ion binding to extracellular gate of a sodium-dependent aspartate transporter

AU - Boudker, Olga

AU - Ryan, Renae M.

AU - Yernool, Dinesh

AU - Shimamoto, Keiko

AU - Gouaux, Eric

PY - 2007/1/25

Y1 - 2007/1/25

N2 - Secondary transporters are integral membrane proteins that catalyse the movement of substrate molecules across the lipid bilayer by coupling substrate transport to one or more ion gradients, thereby providing a mechanism for the concentrative uptake of substrates. Here we describe crystallographic and thermodynamic studies of GltPh, a sodium (Na+)-coupled aspartate transporter, defining sites for aspartate, two sodium ions and d,l-threo-β-benzyloxyaspartate, an inhibitor. We further show that helical hairpin 2 is the extracellular gate that controls access of substrate and ions to the internal binding sites. At least two sodium ions bind in close proximity to the substrate and these sodium-binding sites, together with the sodium-binding sites in another sodium-coupled transporter, LeuT, define an unwound α-helix as the central element of the ion-binding motif, a motif well suited to the binding of sodium and to participation in conformational changes that accompany ion binding and unbinding during the transport cycle.

AB - Secondary transporters are integral membrane proteins that catalyse the movement of substrate molecules across the lipid bilayer by coupling substrate transport to one or more ion gradients, thereby providing a mechanism for the concentrative uptake of substrates. Here we describe crystallographic and thermodynamic studies of GltPh, a sodium (Na+)-coupled aspartate transporter, defining sites for aspartate, two sodium ions and d,l-threo-β-benzyloxyaspartate, an inhibitor. We further show that helical hairpin 2 is the extracellular gate that controls access of substrate and ions to the internal binding sites. At least two sodium ions bind in close proximity to the substrate and these sodium-binding sites, together with the sodium-binding sites in another sodium-coupled transporter, LeuT, define an unwound α-helix as the central element of the ion-binding motif, a motif well suited to the binding of sodium and to participation in conformational changes that accompany ion binding and unbinding during the transport cycle.

UR - http://www.scopus.com/inward/record.url?scp=33846505059&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33846505059&partnerID=8YFLogxK

U2 - 10.1038/nature05455

DO - 10.1038/nature05455

M3 - Article

C2 - 17230192

AN - SCOPUS:33846505059

VL - 445

SP - 387

EP - 393

JO - Nature

JF - Nature

SN - 0028-0836

IS - 7126

ER -