Conformational Ensembles from Experimental Data and Computer Simulations

Conformational Ensembles from Experimental Data and Computer Simulations

Poster Abstracts

116-POS Board 36 A Direct Interaction of Cholesterol with Monoamine Transporters Prevents Their Out-to- Inward Transition Talia Zeppelin 1 , Lucy K. Ladefoged 3 , Steffen Sinning 2 , Xavier Periole 1 , Birgit Schioett 1,3 . 1 Aarhus University, Aarhus C, Denmark, 2 Translational Neuropsychiatry Unit, Aarhus C, Denmark, 3 Aarhus University, Aarhus C, Denmark. Monoamine transporters (MATs) carry out neurotransmitter reuptake from the synaptic cleft, which is a key step targeted in treatment of neurological disorders. Cholesterol, a major component of the synaptic plasma membrane, has been shown to exhibit a modulatory effect on MATs, and recent crystal structures of the dopamine transporter (DAT) in the presence of two conserved cholesterol molecules substantiate the hypothesis of a direct protein-cholesterol interaction. We performed extensive all-atom molecular dynamics (MD) simulations of DAT with and without cholesterol bound. In the absence of cholesterol, DAT undergoes structural changes reflecting early events of transport: transition to an inward-facing conformation. In contrast, in the presence of cholesterol these conformational changes are inhibited presumably by a stabilizing interaction of cholesterol at the intracellular side of TM5. We further provide evidence, from using coarse-grained MD simulations, that the cholesterol sites observed in the DAT crystal structures are conserved in all human MATs, suggesting that this effect might extend to the entire family.

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