Evaluation and biological properties of reactive ligands for the mapping of the glycine site on the N-methyl-D-aspartate (NMDA) receptor.
The glycine-binding site of the N-methyl-D-aspartate (NMDA) receptor, given its potential as pharmacological target, has been thoroughly studied by structure-activity relationships, which has made possible its description in terms of spatial limits and interactions of various types. A structural model, based on mutational analysis and sequence alignements, has been proposed. Yet, the amino acid residues responsible for the interactions with the ligand have not been unambiguously characterized. To evidence nucleophilic pocket-lining residues, we have designed and synthesized reactive glycine-site ligands derived from 3-substituted 4-hydroxy-quinolin-2(1H)-ones by introducing various electrophilic groups at different positions of the molecule. These ligands were found to have high affinity at the glycine site and to be functional antagonists by inhibiting glycine/glutamate-induced currents in transfected oocytes. The correlation between their potency and their substitution pattern was strictly consistent with previously established structure-activity relationships. Most ligands displayed intrinsic reactivity toward cysteine, but none inactivated wild-type receptors. This is consistent with the model since it indicates the absence of exposed cysteine in the glycine-binding site. A strategy of cysteine incorporation by point mutations at selected polypeptide positions will create unambiguously localized targets for our reactive probes.
Kreimeyer
A
A
Laboratoire de Chimie Bioorganique, CNRS-UMR 7514, Faculté de Pharmacie, Université Louis Pasteur, Strasbourg, B.P. 24, F-67401 Illkirch Cedex, France.
Laube
B
B
Sturgess
M
M
Goeldner
M
M
Foucaud
B
B
D000818:Animals; D001667:Binding, Competitive; D001921:Brain / Q000378:metabolism; D004594:Electrophysiology; D018691:Excitatory Amino Acid Antagonists / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D005998:Glycine / Q000494:pharmacology; D066298:In Vitro Techniques; D008024:Ligands; D009865:Oocytes; D011804:Quinolines / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D011869:Radioligand Assay; D051381:Rats; D018009:Receptors, Glycine / Q000096:biosynthesis / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate / Q000096:biosynthesis / Q000378:metabolism*; D013329:Structure-Activity Relationship; D014982:Xenopus laevis
D018691:Excitatory Amino Acid Antagonists; D008024:Ligands; D011804:Quinolines; D018009:Receptors, Glycine; D016194:Receptors, N-Methyl-D-Aspartate; D005998:Glycine