Abstract
The serotonin transporter (SERT), responsible for the reuptake of released serotonin, serves as a major target for antidepressants and psychostimulants. Nevertheless, refining the mechanistic models for SERT remains challenging. Here, we expand the molecular understanding of the binding of ions, substrates, and inhibitors to SERT by incorporating the fluorescent non-canonical amino acid Anap through genetic code expansion. We elucidate steady-state changes in conformational dynamics of purified SERT with Anap inserted at intracellular- or extracellular sites. This uncovers the competitive mechanisms underlying cation binding and assigns distinct binding- and allosteric coupling patterns for several inhibitors and substrates. Finally, we track in real-time conformational transitions in response to the interaction with Na+ or serotonin. In this work, we present a methodological platform reporting on SERT conformational dynamics, which together with other approaches will deepen our insights into the molecular mechanisms of SERT.
Original language | English |
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Article number | 9267 |
Journal | Nature Communications |
Volume | 15 |
Issue number | 1 |
ISSN | 2041-1723 |
DOIs | |
Publication status | Published - 2024 |
Bibliographical note
Funding Information:We would like to thank Jonas H. Steffen for technical assistance with the stopped-flow equipment, generously provided for our use by Professor Michael J. Davies. We thank Sarah Bargmeyer for thorough revision of the manuscript. Anton Turaev is thanked for inspiring us to use what we refer to as spectral ratio. The financial support for this work was provided by the Novo Nordic Foundation (NNF22OC0079091 to C.J.L.), the Independent Research Fund Denmark (1030-00036B to C.J.L.), and the Carlsberg Foundation (CF20-0345 to C.J.L.).
Publisher Copyright:
© The Author(s) 2024.