Probing the Impact of Temperature and Substrates on the Conformational Dynamics of the Neurotransmitter:Sodium symporter LeuT.

The crucial function of neurotransmitter:sodium symporters (NSS) in facilitating the reuptake of neurotransmitters into neuronal cells makes them attractive drug targets for treating multiple mental diseases. Due to the challenges in working with eukaryotic NSS proteins, LeuT, a prokaryotic amino acid transporter, has served as a model protein for studying structure-function relationships of NSS family proteins. With hydrogen-deuterium exchange mass spectrometry (HDX-MS), slow unfolding/refolding kinetics were identified in multiple regions of LeuT, suggesting that substrate translocation involves cooperative fluctuations of helical stretches.

Probing the conformational impact of detergents on the integral membrane protein LeuT by global HDX-MS.

Neurotransmitter:sodium symporters (NSS) are integral membrane proteins (IMP), responsible for reuptake of neurotransmitters from the synaptic cleft. Due to challenges in production of mammalian NSS in their active form, the prokaryotic hydrophobic amino acid transporter, LeuT, served here as a steadfast model for elucidation of structure-function relationship. As NSS proteins reside within phospholipid bilayer, they require stabilization by artificial membrane systems upon their extraction.