X-ray structure of LeuT in an inward-facing occluded conformation reveals mechanism of substrate release
Year: 2020
Type: article
Abstract: Neurotransmitter:sodium symporters (NSS) are conserved from bacteria to man and serve as targets for drugs, including antidepressants and psychostimulants. Here we report the X-ray structure of the prokaryotic NSS member, LeuT, in a Na+/substrate-bound, inward-facing occluded conformation. To obtain this structure, we were guided by findings from single-molecule fluorescence spectroscopy and molecular dynamics simulations indicating that L-Phe binding and mutation of the conserved N-terminal Trp8 to Ala both promote an inward-facing state. Compared to the outward-facing occluded conformation, our structure reveals a major tilting of the cytoplasmic end of transmembrane segment (TM) 5, which, together with release of the N-terminus but without coupled movement of TM1, opens a wide cavity towards the second Na+ binding site. The structure of this key intermediate in the LeuT transport cycle, in the context of other NSS structures, leads to the proposal of an intracellular release mechanism of substrate and ions in NSS proteins.
Source: Nature Communications
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $5,380
Funders: U.S. Department of Energy, Aarhus Universitet, National Energy Research Scientific Computing Center, European Commission, Lundbeckfonden, Paul Scherrer Institut, Novo Nordisk Fonden, H. Lundbeck A/S, DanScatt, National Institutes of Health, Office of Science, Weill Cornell Medical College, Medical Research Council, National Institute on Drug Abuse, Oak Ridge National Laboratory
Awards: G1008403547, G1054401548, G121915436, G122673668, G1286236842, G1370369358, G1414775356, G1528409558, EUROPEAN DRUG INITIATIVE ON CHANNELS AND TRANSPORTERS, G1551050291, G1645119126, G1677143136, G1816284028, G19705060, G203625172, G2362171662, Structure and Function of Neurotransmitter Transporters, G2584197162, G2988778103, G3049477530, G3083819904, G3128856208, G3142975788, G365575497, G3739291073, G382641700, Probing mechanisms of amphetamine action at plasma membrane and vesicular transporters in vitro and in vivo, G419881185, G42916606, G4423657506, G4501827968, G4960985608, G498139845, G5076365615, G5278849166, G5296923526, G54641898, G5653183131, G5952236543, G6486853205, G660579501, G6652958823, G675320460, G687812832, G6887223231, G6911681599, G7140345613, G7651947074, G805243471, G8214903687, G8269158468, G8906985441, G9000018529, G969889393
OpenAlex ID: W3008935525