Identification of the benztropine analog [125I]GA II 34 binding site on the human dopamine transporter
Autor: | Akula Bala Pramod, John R. Lever, Danielle Krout, L. Keith Henry, Michael J. Tomlinson, Roxanne A. Vaughan, Amy Hauck Newman |
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Rok vydání: | 2019 |
Předmět: |
0301 basic medicine
biology Photoaffinity labeling Tropane Cell Biology Pharmacology Benztropine Reuptake 03 medical and health sciences Cellular and Molecular Neuroscience chemistry.chemical_compound 030104 developmental biology 0302 clinical medicine Neurochemical chemistry Dopamine biology.protein medicine Binding site 030217 neurology & neurosurgery Dopamine transporter medicine.drug |
Zdroj: | Neurochemistry International. 123:34-45 |
ISSN: | 0197-0186 |
Popis: | The dopamine transporter (DAT) is a neuronal membrane protein that is responsible for reuptake of dopamine (DA) from the synapse and functions as a major determinant in control of DA neurotransmission. Cocaine and many psychostimulant drugs bind to DAT and block reuptake, inducing DA overflow that forms the neurochemical basis for euphoria and addiction. Paradoxically, however, some ligands such as benztropine (BZT) bind to DAT and inhibit reuptake but do not produce these effects, and it has been hypothesized that differential mechanisms of binding may stabilize specific transporter conformations that affect downstream neurochemical or behavioral outcomes. To investigate the binding mechanisms of BZT on DAT we used the photoaffinity BZT analog [125I]N-[n-butyl-4-(4‴-azido-3‴-iodophenyl)]-4',4″-difluoro-3α-(diphenylmethoxy)tropane ([125I]GA II 34) to identify the site of cross-linking and predict the binding pose relative to that of previously-examined cocaine photoaffinity analogs. Biochemical findings show that adduction of [125I]GA II 34 occurs at residues Asp79 or Leu80 in TM1, with molecular modeling supporting adduction to Leu80 and a pharmacophore pose in the central S1 site similar to that of cocaine and cocaine analogs. Substituted cysteine accessibility method protection analyses verified these findings, but identified some differences in structural stabilization relative to cocaine that may relate to BZT neurochemical outcomes. |
Databáze: | OpenAIRE |
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