TY - JOUR

T1 - Substrate-modulated unwinding of transmembrane helices in the NSS transporter LeuT

T2 - Recommended in F1000Prime as being of special significance in its field by F1000 Faculty Member Robert Vandenberg

AU - Merkle, Patrick Sascha

AU - Gotfryd, Kamil

AU - Cuendet, Michel A

AU - Leth-Espensen, Katrine Zinck

AU - Gether, Ulrik

AU - Løland, Claus Juul

AU - Rand, Kasper Dyrberg

N1 - Recommended in F1000Prime as being of special significance in its field by F1000 Faculty Member Robert Vandenberg.

PY - 2018

Y1 - 2018

N2 - LeuT, a prokaryotic member of the neurotransmitter:sodium symporter (NSS) family, is an established structural model for mammalian NSS counterparts. We investigate the substrate translocation mechanism of LeuT by measuring the solution-phase structural dynamics of the transporter in distinct functional states by hydrogen/deuterium exchange mass spectrometry (HDX-MS). Our HDX-MS data pinpoint LeuT segments involved in substrate transport and reveal for the first time a comprehensive and detailed view of the dynamics associated with transition of the transporter between outward- and inward-facing configurations in a Na+- and K+-dependent manner. The results suggest that partial unwinding of transmembrane helices 1/5/6/7 drives LeuT from a substrate-bound, outward-facing occluded conformation toward an inward-facing open state. These hitherto unknown, large-scale conformational changes in functionally important transmembrane segments, observed for LeuT in detergent-solubilized form and when embedded in a native-like phospholipid bilayer, could be of physiological relevance for the translocation process.

AB - LeuT, a prokaryotic member of the neurotransmitter:sodium symporter (NSS) family, is an established structural model for mammalian NSS counterparts. We investigate the substrate translocation mechanism of LeuT by measuring the solution-phase structural dynamics of the transporter in distinct functional states by hydrogen/deuterium exchange mass spectrometry (HDX-MS). Our HDX-MS data pinpoint LeuT segments involved in substrate transport and reveal for the first time a comprehensive and detailed view of the dynamics associated with transition of the transporter between outward- and inward-facing configurations in a Na+- and K+-dependent manner. The results suggest that partial unwinding of transmembrane helices 1/5/6/7 drives LeuT from a substrate-bound, outward-facing occluded conformation toward an inward-facing open state. These hitherto unknown, large-scale conformational changes in functionally important transmembrane segments, observed for LeuT in detergent-solubilized form and when embedded in a native-like phospholipid bilayer, could be of physiological relevance for the translocation process.

U2 - 10.1126/sciadv.aar6179

DO - 10.1126/sciadv.aar6179

M3 - Journal article

C2 - 29756037

VL - 4

JO - Science advances

JF - Science advances

SN - 2375-2548

IS - 5

M1 - eaar6179

ER -