1
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Gao L, Wang W, Wang X, Yang F, Xie L, Shen J, Brimble MA, Xiao Q, Yao SQ. Fluorescent probes for bioimaging of potential biomarkers in Parkinson's disease. Chem Soc Rev 2021; 50:1219-1250. [DOI: 10.1039/d0cs00115e] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This review comprehensively summarizes various types of fluorescent probes for PD and their applications for detection of various PD biomarkers.
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Affiliation(s)
- Liqian Gao
- School of Pharmaceutical Sciences (Shenzhen)
- Sun Yat-sen University
- Shenzhen, 518107
- P. R. China
- Department of Chemistry
| | - Wei Wang
- School of Pharmaceutical Sciences (Shenzhen)
- Sun Yat-sen University
- Shenzhen, 518107
- P. R. China
- Department of Chemistry
| | - Xuan Wang
- School of Pharmaceutical Sciences (Shenzhen)
- Sun Yat-sen University
- Shenzhen, 518107
- P. R. China
| | - Fen Yang
- School of Pharmaceutical Sciences (Shenzhen)
- Sun Yat-sen University
- Shenzhen, 518107
- P. R. China
| | - Liuxing Xie
- School of Pharmaceutical Sciences (Shenzhen)
- Sun Yat-sen University
- Shenzhen, 518107
- P. R. China
| | - Jun Shen
- Department of Radiology
- Sun Yat-Sen Memorial Hospital
- Sun Yat-Sen University
- Guangzhou
- P. R. China
| | - Margaret A. Brimble
- School of Chemical Sciences
- The University of Auckland
- Auckland 1010
- New Zealand
| | - Qicai Xiao
- School of Pharmaceutical Sciences (Shenzhen)
- Sun Yat-sen University
- Shenzhen, 518107
- P. R. China
- Department of Chemistry
| | - Shao Q. Yao
- Department of Chemistry
- National University of Singapore
- Singapore
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2
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Krout D, Pramod AB, Dahal RA, Tomlinson MJ, Sharma B, Foster JD, Zou MF, Boatang C, Newman AH, Lever JR, Vaughan RA, Henry LK. Inhibitor mechanisms in the S1 binding site of the dopamine transporter defined by multi-site molecular tethering of photoactive cocaine analogs. Biochem Pharmacol 2017; 142:204-215. [PMID: 28734777 DOI: 10.1016/j.bcp.2017.07.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 07/17/2017] [Indexed: 10/19/2022]
Abstract
Dopamine transporter (DAT) blockers like cocaine and many other abused and therapeutic drugs bind and stabilize an inactive form of the transporter inhibiting reuptake of extracellular dopamine (DA). The resulting increases in DA lead to the ability of these drugs to induce psychomotor alterations and addiction, but paradoxical findings in animal models indicate that not all DAT antagonists induce cocaine-like behavioral outcomes. How this occurs is not known, but one possibility is that uptake inhibitors may bind at multiple locations or in different poses to stabilize distinct conformational transporter states associated with differential neurochemical endpoints. Understanding the molecular mechanisms governing the pharmacological inhibition of DAT is therefore key for understanding the requisite interactions for behavioral modulation and addiction. Previously, we leveraged complementary computational docking, mutagenesis, peptide mapping, and substituted cysteine accessibility strategies to identify the specific adduction site and binding pose for the crosslinkable, photoactive cocaine analog, RTI 82, which contains a photoactive azide attached at the 2β position of the tropane pharmacophore. Here, we utilize similar methodology with a different cocaine analog N-[4-(4-azido-3-I-iodophenyl)-butyl]-2-carbomethoxy-3-(4-chlorophenyl)tropane, MFZ 2-24, where the photoactive azide is attached to the tropane nitrogen. In contrast to RTI 82, which crosslinked into residue Phe319 of transmembrane domain (TM) 6, our findings show that MFZ 2-24 adducts to Leu80 in TM1 with modeling and biochemical data indicating that MFZ 2-24, like RTI 82, occupies the central S1 binding pocket with the (+)-charged tropane ring nitrogen coordinating with the (-)-charged carboxyl side chain of Asp79. The superimposition of the tropane ring in the three-dimensional binding poses of these two distinct ligands provides strong experimental evidence for cocaine binding to DAT in the S1 site and the importance of the tropane moiety in competitive mechanisms of DA uptake inhibition. These findings set a structure-function baseline for comparison of typical and atypical DAT inhibitors and how their interactions with DAT could lead to the loss of cocaine-like behaviors.
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Affiliation(s)
- Danielle Krout
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 1301 North Columbia Road, Grand Forks, ND 58202, USA
| | - Akula Bala Pramod
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 1301 North Columbia Road, Grand Forks, ND 58202, USA
| | - Rejwi Acharya Dahal
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 1301 North Columbia Road, Grand Forks, ND 58202, USA
| | - Michael J Tomlinson
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 1301 North Columbia Road, Grand Forks, ND 58202, USA
| | - Babita Sharma
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 1301 North Columbia Road, Grand Forks, ND 58202, USA
| | - James D Foster
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 1301 North Columbia Road, Grand Forks, ND 58202, USA
| | - Mu-Fa Zou
- Medicinal Chemistry Section, National Institute on Drug Abuse - Intramural Research Program, Baltimore, MD 21224, USA
| | - Comfort Boatang
- Medicinal Chemistry Section, National Institute on Drug Abuse - Intramural Research Program, Baltimore, MD 21224, USA
| | - Amy Hauck Newman
- Medicinal Chemistry Section, National Institute on Drug Abuse - Intramural Research Program, Baltimore, MD 21224, USA
| | - John R Lever
- Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO, 65201, USA; Department of Radiology and Radiopharmaceutical Sciences Institute, University of Missouri, Columbia, MO 65211, USA
| | - Roxanne A Vaughan
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 1301 North Columbia Road, Grand Forks, ND 58202, USA.
| | - L Keith Henry
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 1301 North Columbia Road, Grand Forks, ND 58202, USA.
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3
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Kumar V, Yarravarapu N, Lapinsky DJ, Perley D, Felts B, Tomlinson MJ, Vaughan RA, Henry LK, Lever JR, Newman AH. Novel Azido-Iodo Photoaffinity Ligands for the Human Serotonin Transporter Based on the Selective Serotonin Reuptake Inhibitor (S)-Citalopram. J Med Chem 2015; 58:5609-19. [PMID: 26153715 PMCID: PMC4515784 DOI: 10.1021/acs.jmedchem.5b00682] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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Three photoaffinity ligands (PALs)
for the human serotonin transporter
(hSERT) were synthesized based on the selective serotonin reuptake
inhibitor (SSRI), (S)-citalopram (1).
The classic 4-azido-3-iodo-phenyl group was appended to either the
C-1 or C-5 position of the parent molecule, with variable-length linkers,
to generate ligands 15, 22, and 26. These ligands retained high to moderate affinity binding (Ki = 24–227 nM) for hSERT, as assessed
by [3H]5-HT transport inhibition. When tested against Ser438Thr
hSERT, all three PALs showed dramatic rightward shifts in inhibitory
potency, with Ki values ranging from 3.8
to 9.9 μM, consistent with the role of Ser438 as a key residue
for high-affinity binding of many SSRIs, including (S)-citalopram. Photoactivation studies demonstrated irreversible adduction
to hSERT by all ligands, but the reduced (S)-citalopram
inhibition of labeling by [125I]15 compared
to that by [125I]22 and [125I]26 suggests differences in binding mode(s). These radioligands
will be useful for characterizing the drug–protein binding
interactions for (S)-citalopram at hSERT.
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Affiliation(s)
- Vivek Kumar
- †Medicinal Chemistry Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Nageswari Yarravarapu
- ‡Division of Pharmaceutical Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, Pennsylvania 15282, United States
| | - David J Lapinsky
- ‡Division of Pharmaceutical Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, Pennsylvania 15282, United States
| | - Danielle Perley
- §Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202, United States
| | - Bruce Felts
- §Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202, United States
| | - Michael J Tomlinson
- §Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202, United States
| | - Roxanne A Vaughan
- §Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202, United States
| | - L Keith Henry
- §Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202, United States
| | - John R Lever
- ∥Department of Radiology, University of Missouri, One Hospital Drive, Columbia, Missouri 65212, United States.,⊥Harry S. Truman Memorial Veterans' Hospital, 800 Hospital Drive, Columbia, Missouri 65201, United States
| | - Amy Hauck Newman
- †Medicinal Chemistry Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
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Bartuschat AL, Schellhorn T, Hübner H, Gmeiner P, Heinrich MR. Fluoro-substituted phenylazocarboxamides: Dopaminergic behavior and N-arylating properties for irreversible binding. Bioorg Med Chem 2015; 23:3938-47. [DOI: 10.1016/j.bmc.2014.12.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 12/08/2014] [Accepted: 12/10/2014] [Indexed: 10/24/2022]
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Lapinsky DJ, Yarravarapu N, Nolan TL, Surratt CK, Lever JR, Tomlinson M, Vaughan RA, Deutsch HM. Evolution of a Compact Photoprobe for the Dopamine Transporter Based on (±)-threo-Methylphenidate. ACS Med Chem Lett 2012; 3:378-382. [PMID: 23066448 DOI: 10.1021/ml3000098] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The development of photoaffinity ligands for determining covalent points of attachment to the dopamine transporter (DAT) has predominantly focused on tropane-based compounds bearing variable-length linkers between the photoreactive group and inhibitor pharmacophore. In order to expand the array of photoprobes useful for mapping inhibitor-binding pockets within the DAT, a compact non-tropane ligand was synthesized featuring a photoreactive azide and iodine tag directly attached to the aromatic ring of (±)-threo-methylphenidate. (±)-threo-4-Azido-3-iodomethylphenidate ((±)-6); K(i) = 4.0 ± 0.8 nM) displayed high affinity for hDAT. Moreover, a radioiodinated analog of (±)-6 demonstrated covalent ligation to the DAT in cultured cells and rat striatal membranes, thus suggesting the potential utility of this photoprobe in DAT structure-function studies.
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Affiliation(s)
- David J. Lapinsky
- Division of
Pharmaceutical Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh,
Pennsylvania 15282, United States
| | - Nageswari Yarravarapu
- Division of
Pharmaceutical Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh,
Pennsylvania 15282, United States
| | - Tammy L. Nolan
- Division of
Pharmaceutical Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh,
Pennsylvania 15282, United States
| | - Christopher K. Surratt
- Division of
Pharmaceutical Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh,
Pennsylvania 15282, United States
| | - John R. Lever
- Departments of Radiology, and
Medical Pharmacology and Physiology, One Hospital Drive, University of Missouri, Columbia, Missouri 65212, United
States
- Harry S. Truman Veterans Administration Medical Center, 800 Hospital Drive, Columbia,
Missouri 65201, United States
| | - Michael Tomlinson
- Department of Biochemistry and
Molecular Biology, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North
Dakota 58202, United States
| | - Roxanne A. Vaughan
- Department of Biochemistry and
Molecular Biology, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North
Dakota 58202, United States
| | - Howard M. Deutsch
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332,
United States
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6
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Lapinsky DJ, Aggarwal S, Nolan TL, Surratt CK, Lever JR, Acharya R, Vaughan RA, Pandhare A, Blanton MP. (±)-2-(N-tert-Butylamino)-3'-[(125)I]-iodo-4'-azidopropiophenone: a dopamine transporter and nicotinic acetylcholine receptor photoaffinity ligand based on bupropion (Wellbutrin, Zyban). Bioorg Med Chem Lett 2012; 22:523-6. [PMID: 22119468 PMCID: PMC3249008 DOI: 10.1016/j.bmcl.2011.10.086] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 10/26/2011] [Indexed: 11/24/2022]
Abstract
Towards addressing the knowledge gap of how bupropion interacts with the dopamine transporter (DAT) and nicotinic acetylcholine receptors (nAChRs), a ligand was synthesized in which the chlorine of bupropion was isosterically replaced with an iodine and a photoreactive azide was added to the 4'-position of the aromatic ring. Analog (±)-3 (SADU-3-72) demonstrated modest DAT and α4β2 nAChR affinity. A radioiodinated version was shown to bind covalently to hDAT expressed in cultured cells and affinity-purified, lipid-reincorporated human α4β2 neuronal nAChRs. Co-incubation of (±)-[(125)I]-3 with non-radioactive (±)-bupropion or (-)-cocaine blocked labeling of these proteins. Compound (±)-[(125)I]-3 represents the first successful example of a DAT and nAChR photoaffinity ligand based on the bupropion scaffold. Such ligands are expected to assist in mapping bupropion-binding pockets within plasma membrane monoamine transporters and ligand-gated nAChR ion channels.
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Affiliation(s)
- David J Lapinsky
- Division of Pharmaceutical Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282, United States.
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7
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Lapinsky DJ, Velagaleti R, Yarravarapu N, Liu Y, Huang Y, Surratt CK, Lever JR, Foster JD, Acharya R, Vaughan RA, Deutsch HM. Azido-iodo-N-benzyl derivatives of threo-methylphenidate (Ritalin, Concerta): Rational design, synthesis, pharmacological evaluation, and dopamine transporter photoaffinity labeling. Bioorg Med Chem 2011; 19:504-12. [PMID: 21129986 PMCID: PMC3023924 DOI: 10.1016/j.bmc.2010.11.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 10/25/2010] [Accepted: 11/01/2010] [Indexed: 11/20/2022]
Abstract
In contrast to tropane-based compounds such as benztropine and cocaine, non-tropane-based photoaffinity ligands for the dopamine transporter (DAT) are relatively unexplored. Towards addressing this knowledge gap, ligands were synthesized in which the piperidine nitrogen of 3- and 4-iodomethylphenidate was substituted with a benzyl group bearing a photoreactive azide. Analog (±)-3a demonstrated modest DAT affinity and a radioiodinated version was shown to bind covalently to rat striatal DAT and hDAT expressed in cultured cells. Co-incubation of (±)-3a with nonradioactive d-(+)-methylphenidate or (-)-2-β-carbomethoxy-3-β-(4-fluorophenyl)tropane (β-CFT, WIN-35,428, a cocaine analog) blocked DAT labeling. Compound (±)-3a represents the first successful example of a DAT photoaffinity ligand based on the methylphenidate scaffold. Such ligands are expected to assist in mapping non-tropane ligand-binding pockets within plasma membrane monoamine transporters.
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Affiliation(s)
- David J Lapinsky
- Division of Pharmaceutical Sciences, Duquesne University Mylan School of Pharmacy, 600 Forbes Avenue, Pittsburgh, PA 15282, USA.
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8
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Lapinsky DJ, Aggarwal S, Huang Y, Surratt CK, Lever JR, Foster JD, Vaughan RA. A novel photoaffinity ligand for the dopamine transporter based on pyrovalerone. Bioorg Med Chem 2009; 17:3770-4. [PMID: 19442525 PMCID: PMC2696686 DOI: 10.1016/j.bmc.2009.04.057] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Revised: 04/22/2009] [Accepted: 04/24/2009] [Indexed: 10/20/2022]
Abstract
Non-tropane-based photoaffinity ligands for the dopamine transporter (DAT) are relatively unexplored in contrast to tropane-based compounds such as cocaine. In order to fill this knowledge gap, a ligand was synthesized in which the aromatic ring of pyrovalerone was substituted with a photoreactive azido group. The analog 1-(4-azido-3-iodophenyl)-2-pyrrolidin-1-yl-pentan-1-one demonstrated appreciable binding affinity for the DAT (K(i)=78+/-18 nM), suggesting the potential utility of a radioiodinated version in structure-function studies of this protein.
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Affiliation(s)
- David J Lapinsky
- Division of Pharmaceutical Sciences, Duquesne University Mylan School of Pharmacy, 600 Forbes Avenue, Pittsburgh, PA 15282, USA.
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9
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Murthy V, Martin TJ, Kim S, Davies HML, Childers SR. In Vivo Characterization of a Novel Phenylisothiocyanate Tropane Analog at Monoamine Transporters in Rat Brain. J Pharmacol Exp Ther 2008; 326:587-95. [DOI: 10.1124/jpet.108.138842] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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10
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Parnas ML, Gaffaney JD, Zou MF, Lever JR, Newman AH, Vaughan RA. Labeling of dopamine transporter transmembrane domain 1 with the tropane ligand N-[4-(4-azido-3-[125I]iodophenyl)butyl]-2beta-carbomethoxy-3beta-(4-chlorophenyl)tropane implicates proximity of cocaine and substrate active sites. Mol Pharmacol 2008; 73:1141-50. [PMID: 18216182 DOI: 10.1124/mol.107.043679] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The novel photoaffinity ligand N-[4-(4-azido-3-(125)I-iodophenyl)-butyl]-2-beta-carbomethoxy-3beta-(4-chlorophenyl) tropane ([(125)I]MFZ 2-24) was used to investigate the site for cocaine binding on the dopamine transporter (DAT). [(125)I]MFZ 2-24 irreversibly labeled both rat striatal and expressed human DAT with high affinity and appropriate pharmacological specificity. Tryptic proteolysis of [(125)I]MFZ 2-24 labeled DAT followed by epitope-specific immunoprecipitation demonstrated that the ligand becomes adducted almost exclusively to transmembrane domains (TMs) 1-2. Further localization of [(125)I]MFZ 2-24 incorporation achieved by proteolyzing labeled wild-type and methionine mutant DATs with cyanogen bromide identified the sequence between residues 68 and 80 in TM1 as the ligand adduction site. This is in marked contrast to the previously identified attachment of the photoaffinity label [(125)I]RTI 82 in TM6. Because [(125)I]MFZ 2-24 and [(125)I]RTI 82 possess identical tropane pharmacophores and differ only in the placement of the reactive azido moieties, their distinct incorporation profiles identify the regions of the protein adjacent to different aspects of the cocaine molecule. These findings thus strongly support the direct interaction of cocaine on DAT with TM1 and TM6, both of which have been implicated by mutagenesis and homology to a bacterial leucine transporter as active sites for substrates. These results directly establish the proximity of TMs 1 and 6 in DAT and suggest that the mechanism of transport inhibition by cocaine involves close interactions with multiple regions of the substrate permeation pathway.
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Affiliation(s)
- M Laura Parnas
- Department of Biochemistry and Molecular Biology, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, USA
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11
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Vaughan RA, Sakrikar DS, Parnas ML, Adkins S, Foster JD, Duval RA, Lever JR, Kulkarni SS, Hauck-Newman A. Localization of cocaine analog [125I]RTI 82 irreversible binding to transmembrane domain 6 of the dopamine transporter. J Biol Chem 2007; 282:8915-25. [PMID: 17255098 DOI: 10.1074/jbc.m610633200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The site of cocaine binding on the dopamine transporter (DAT) was investigated using the photoactivatable irreversible cocaine analog [125I]3beta-(p-chlorophenyl)tropane-2beta-carboxylic acid, 4'-azido-3'-iodophenylethyl ester ([125I]RTI 82). The incorporation site of this compound was mapped to transmembrane domains (TMs) 4-6 using epitope-specific immunoprecipitation of trypsin fragments and further localized using cyanogen bromide (CNBr), which hydrolyzes proteins on the C-terminal side of methionine residues. CNBr hydrolysis of [125I]RTI 82-labeled rat striatal and expressed human DATs produced fragments of approximately 5-10 kDa consistent with labeling between Met(271/272) or Met(290) in TM5 to Met(370/371) in TM7. To further define the incorporation site, substitution mutations were made that removed endogenous methionines and inserted exogenous methionines in combinations that would generate labeled CNBr fragments of distinct masses depending on the labeling site. The results obtained were consistent with the presence of TM6 but not TMs 4, 5, or 7 in the labeled fragments, with additional support for these conclusions obtained by epitope-specific immunoprecipitation and secondary digestion of CNBr fragments with endoproteinase Lys-C. The final localization of [125I]RTI 82 incorporation to rat DAT Met(290)-Lys(336) and human DAT I291M to R344M provides positive evidence for the proximity of cocaine binding to TM6. Residues in and near DAT TM6 regulate transport and transport-dependent conformational states, and TM6 forms part of the substrate permeation pathway in the homologous Aquifex aeolicus leucine transporter. Cocaine binding near TM6 may thus overlap the dopamine translocation pathway and function to inhibit TM6 structural rearrangements necessary for transport.
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Affiliation(s)
- Roxanne A Vaughan
- Department of Biochemistry and Molecular Biology, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203-9037, USA.
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12
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Filer CN. The synthesis of dopaminergic radioligands labelled with tritium and iodine-125. J Labelled Comp Radiopharm 2007. [DOI: 10.1002/jlcr.1399] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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13
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Newman AH, Cha JH, Cao J, Kopajtic T, Katz JL, Parnas ML, Vaughan R, Lever JR. Design and Synthesis of a Novel Photoaffinity Ligand for the Dopamine and Serotonin Transporters Based on 2β-Carbomethoxy-3β-biphenyltropane. J Med Chem 2006; 49:6621-5. [PMID: 17064081 DOI: 10.1021/jm0603973] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Tropane-based photoaffinity ligands covalently bind to discrete points of attachment on the dopamine transporter (DAT). To further explore structure-activity relations, a ligand in which the photoactivated group was extended from the 3-position of the tropane ring was synthesized from cocaine via a Stille or Suzuki coupling strategy. 3-(4'-Azido-3'-iodo-biphenyl-4-yl)-8-methyl-8-aza-bicyclo[3.2.1]octane-2-carboxylic acid methyl ester (11; K(i) = 15.1 +/- 2.2 nM) demonstrated high binding affinity for the DAT. Moreover, this compound showed moderate binding affinity for the serotonin transporter (SERT, K(i) = 109 +/- 14 nM), suggesting the potential utility of [(125)I]11 in both DAT and SERT protein structure studies.
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Affiliation(s)
- Amy Hauck Newman
- Medicinal Chemistry and Psychobiology Sections, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health/DHHS, Baltimore, MD, USA.
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15
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Surratt CK, Ukairo OT, Ramanujapuram S. Recognition of psychostimulants, antidepressants, and other inhibitors of synaptic neurotransmitter uptake by the plasma membrane monoamine transporters. AAPS JOURNAL 2005; 7:E739-51. [PMID: 16353950 PMCID: PMC2751276 DOI: 10.1208/aapsj070374] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The plasma membrane monoamine transporters terminate neurotransmission by removing dopamine, norepinephrine, or serotonin from the synaptic cleft between neurons. Specific inhibitors for these transporters, including the abused psychostimulants cocaine and amphetamine and the tricyclic and SSRI classes of antidepressants, exert their physiological effects by interfering with synaptic uptake and thus prolonging the actions of the monoamine. Pharmacological, biochemical, and immunological characterization of the many site-directed, chimeric, and deletion mutants generated for the plasma membrane monoamine transporters have revealed much about the commonalities and dissimilarities between transporter substrate, ion, and inhibitor binding sites. Mutations that alter the binding affinity or substrate uptake inhibition potency of inhibitors by at least 3-fold are the focus of this review. These findings are clarifying the picture regarding substrate uptake inhibitor/transporter protein interactions at the level of the drug pharmacophore and the amino acid residue, information necessary for rational design of novel medications for substance abuse and a variety of psychiatric disorders.
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Affiliation(s)
- Christopher K Surratt
- Division of Pharmaceutical Sciences, Mylan School of Pharmacy, Duquesne University, Pittsburgh, PA 15282, USA.
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