TY - JOUR
T1 - Direct assessment of substrate binding to the Neurotransmitter:Sodium Symporter LeuT by solid state NMR
AU - Erlendsson, Simon
AU - Gotfryd, Kamil
AU - Larsen, Flemming Hofmann
AU - Mortensen, Jonas Sigurd
AU - Geiger, Michel-Andreas
AU - van Rossum, Barth-Jan
AU - Oschkinat, Hartmut
AU - Gether, Ulrik
AU - Teilum, Kaare
AU - Løland, Claus Juul
PY - 2017
Y1 - 2017
N2 - The Neurotransmitter:Sodium Symporters (NSSs) represent an important class of proteins mediating sodium-dependent uptake of neurotransmitters from the extracellular space. The substrate binding stoichiometry of the bacterial NSS protein, LeuT, and thus the principal transport mechanism, has been heavily debated. Here we used solid state NMR to specifically characterize the bound leucine ligand and probe the number of binding sites in LeuT. We were able to produce high-quality NMR spectra of substrate bound to microcrystalline LeuT samples and identify one set of sodium-dependent substrate-specific chemical shifts. Furthermore, our data show that the binding site mutants F253A and L400S, which probe the major S1 binding site and the proposed S2 binding site, respectively, retain sodium-dependent substrate binding in the S1 site similar to the wild-type protein. We conclude that under our experimental conditions there is only one detectable leucine molecule bound to LeuT.
AB - The Neurotransmitter:Sodium Symporters (NSSs) represent an important class of proteins mediating sodium-dependent uptake of neurotransmitters from the extracellular space. The substrate binding stoichiometry of the bacterial NSS protein, LeuT, and thus the principal transport mechanism, has been heavily debated. Here we used solid state NMR to specifically characterize the bound leucine ligand and probe the number of binding sites in LeuT. We were able to produce high-quality NMR spectra of substrate bound to microcrystalline LeuT samples and identify one set of sodium-dependent substrate-specific chemical shifts. Furthermore, our data show that the binding site mutants F253A and L400S, which probe the major S1 binding site and the proposed S2 binding site, respectively, retain sodium-dependent substrate binding in the S1 site similar to the wild-type protein. We conclude that under our experimental conditions there is only one detectable leucine molecule bound to LeuT.
U2 - 10.7554/eLife.19314
DO - 10.7554/eLife.19314
M3 - Journal article
C2 - 28117663
VL - 6
JO - eLife
JF - eLife
SN - 2050-084X
M1 - e19314
ER -