Project Details
Projekt
Proton transfer and substrate recognition in SLC17 transporters
Applicants
Professorin Mercedes Alfonso-Prieto, Ph.D.; Professor Dr. Paolo Carloni; Professor Dr. Christoph Fahlke
Subject Area
Biophysics
Term
from 2017 to 2023
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 291198853
Vesicular glutamate transporters (VGLUTs) belong to the SLC17 family of organic anion transporters. They accumulate glutamate in synaptic vesicles and thus represent a major determinant of synaptic strength in excitatory synapses. The recent determination of the structure of the homologous bacterial D-galactonate transporter (DgoT) has opened the way to understand the mechanisms of substrate transport across this family. Two important functional aspects will be investigated here, by a combination of multi-scale molecular simulations, site-directed mutagenesis, heterologous expression, cellular electrophysiology and fluorescence spectroscopy. First, we will provide insights into the molecular basis of the experimentally measured pH dependence of transport in the SLC17 family. Quantum mechanics/molecular mechanics simulations will shed light on the role of the essential acidic residues Glu133 (conserved across DgoT and VGLUTs) and Asp46 (only present in DgoT). These simulations, which fully exploit the parallel computing power available in Jülich, will pinpoint the residues responsible for proton transfer, and the role of these residues in both DgoT and VGLUTs will be further scrutinized in experiments. In addition, we will study important aspects of substrate selectivity in the SLC17 family. Specifically, simulations on the aforementioned DgoT structure, together with experimentally-guided simulations on VGLUT homology models and experiments on both transporters will provide hints on the molecular determinants of substrate selectivity.
DFG Programme
Research Units
