Evolution of a Compact Photoprobe for the Dopamine Transporter Based on (±)-threo-Methylphenidate.
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.
Division of Pharmaceutical Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, Pennsylvania 15282, United States.
David J
DJ
Lapinsky
Nageswari
N
Yarravarapu
Tammy L
TL
Nolan
Christopher K
CK
Surratt
John R
JR
Lever
Michael
M
Tomlinson
Roxanne A
RA
Vaughan
Howard M
HM
Deutsch