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Identification of the benztropine analog [125I]GA II 34 binding site on the human dopamine transporter.
Neurochem Int. 2019 02; 123:34-45.NI

Abstract

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.

Authors+Show Affiliations

Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 1301 North Columbia Road, Grand Forks, ND 58202, United States.Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 1301 North Columbia Road, Grand Forks, ND 58202, United States.Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 1301 North Columbia Road, Grand Forks, ND 58202, United States.Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO, 65201, United States; Department of Radiology and Radiopharmaceutical Sciences Institute, University of Missouri, Columbia, MO 65211, United States.Medicinal Chemistry Section, National Institute on Drug Abuse - Intramural Research Program, Baltimore, MD 21224, United States.Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 1301 North Columbia Road, Grand Forks, ND 58202, United States. Electronic address: keith.henry@med.und.edu.Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 1301 North Columbia Road, Grand Forks, ND 58202, United States. Electronic address: roxanne.vaughan@med.und.edu.

Pub Type(s)

Journal Article
Research Support, N.I.H., Intramural
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

30125594

Citation

Tomlinson, Michael J., et al. "Identification of the Benztropine Analog [125I]GA II 34 Binding Site On the Human Dopamine Transporter." Neurochemistry International, vol. 123, 2019, pp. 34-45.
Tomlinson MJ, Krout D, Pramod AB, et al. Identification of the benztropine analog [125I]GA II 34 binding site on the human dopamine transporter. Neurochem Int. 2019;123:34-45.
Tomlinson, M. J., Krout, D., Pramod, A. B., Lever, J. R., Newman, A. H., Henry, L. K., & Vaughan, R. A. (2019). Identification of the benztropine analog [125I]GA II 34 binding site on the human dopamine transporter. Neurochemistry International, 123, 34-45. https://doi.org/10.1016/j.neuint.2018.08.008
Tomlinson MJ, et al. Identification of the Benztropine Analog [125I]GA II 34 Binding Site On the Human Dopamine Transporter. Neurochem Int. 2019;123:34-45. PubMed PMID: 30125594.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Identification of the benztropine analog [125I]GA II 34 binding site on the human dopamine transporter. AU - Tomlinson,Michael J, AU - Krout,Danielle, AU - Pramod,Akula Bala, AU - Lever,John R, AU - Newman,Amy Hauck, AU - Henry,L Keith, AU - Vaughan,Roxanne A, Y1 - 2018/08/17/ PY - 2018/06/01/received PY - 2018/08/10/revised PY - 2018/08/14/accepted PY - 2018/8/21/pubmed PY - 2019/12/27/medline PY - 2018/8/21/entrez KW - Benztropine KW - Cocaine KW - Molecular modeling KW - Peptide mapping KW - Photoaffinity labeling KW - SCAM SP - 34 EP - 45 JF - Neurochemistry international JO - Neurochem. Int. VL - 123 N2 - 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. SN - 1872-9754 UR - https://www.unboundmedicine.com/medline/citation/30125594/Identification_of_the_benztropine_analog_[125I]GA_II_34_binding_site_on_the_human_dopamine_transporter_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0197-0186(18)30241-9 DB - PRIME DP - Unbound Medicine ER -